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Platelet aggregation response in schizophrenia and prostaglandin E1
Psychiurr.v Research, Elsevier
9, 309-3 I8
309
Platelet Aggregation Prostaglandin El
in Schizophrenia
and
Hisanobu Kaiya, Hirosato Imai, Yayoi Muramatsu, Masakatsu Hajime Fujimura, Soichiro Adachi, and Masuyuki Namba
Nozaki,
Received September 1983.
Response
2, 1983; revised version received Februar_v 2, 1983; accepted February 22,
Abstract. Platelet aggregation response to various stimulants was examined in 18
unmedicated schizophrenic patients, 13 medicated patients, and 13 control subjects. Platelet aggregation response to epinephrine decreased only in unmedicated schizophrenic patients. Clinical improvement in seven patients after neuroleptic medication was significantly correlated with an increase in platelet aggregation response to arachidonic acid, and nonsignificantly to epinephrine, dopamine, and serotonin. The inhibitory effect of prostaglandin El on platelet aggregation response to adenosine diphosphate was investigated in seven unmedicated schizophrenic patients, six medicated patients, and eight controls. The inhibitory effect of prostaglandin E I on platelet aggregation response to adenosine diphosphate was significantly reduced in all unmedicated schizophrenic patients. Neuroleptic medication had some effect in normalizing aberrant sensitivity to prostaglandin E I in those patients, although acute medication induced an adverse reaction in the controls. Key Words. Platelet aggregation
epinephrine,
prostaglandin
response, schizophrenia,
clinical rating scale,
E I.
The platelet is regarded as an excellent tool for the study of biogenic amines and some peptides in psychiatric disorders. Stahl (1977) has reviewed extensively the usefulness and limitations of platelet study as a peripheral model of central nervous system (CNS) monoaminergic neurons. He pointed out that platelets show a greater similarity to serotonergic presynaptic and postsynaptic membranes than to catecholaminergic ones. However, a recent study has shown some evidence suggesting that platelets are also comparable to catecholaminergic neurons (Pletscher, 1981). Therefore, the investigation of platelet aggregation response to various stimulants in schizophrenic patients has aroused considerable interest. The first study of platelet aggregation response in schizophrenia was reported by Boullin et al. (1975), who observed an irreversible platelet aggregation response to serotonin (5-HT) in nine chronic psychiatric patients who were being treated with chlorpromazine (CPZ). The Hisanobu Kaiya. M.D., is Docent, Department of Neuropsychiatry, Gifu University School of Medicine; Hirosato Imai, M.D., and Yayoi Muramatsu are Research Fellows, Department of Pharmacology. Gifu University School of Medicine; Masakatsu Nozaki, Ph.D.. is Docent. Department of Pharmacology, Gifu University School of Medicine; Hajime Fujimura, M.D., is Professor and Chief. Department of Pharmacology, Gifu University School of Medicine; Soichiro Adachi, M.D., is Research Fellow. Department of Neuropaychiatry. Gifu University School of Medicine; and Masuyuki Namba, M.D., is Professor and Chief, Gifu University School of Medicine. (Reprint requests to Dr. H. Kaiya, Department of Neuropsychiatry, Gifu llniversity School of Medicine. Tsukasa-Machi 40. Gifu, Japan.) 0165-1781 ,83 $03.00 0 1983 Elsevier Science Publishers
B.V.
310 incidence of such an irreversible platelet aggregation response in the normal population was reported to be 8% (Besterman and Gillett, 1973). Boullin and Grimes ( 1976) further reported that an enhanced platelet aggregation response in CPZ-treated patients could be induced not only by the administration of 5-HT, but also by dopamine and N-dimethyldopamine. The enhanced platelet aggregation response to 5-HT was associated with clinical improvement in chronic schizophrenic patients receiving fluphenazine decanoate (Orr and Boullin, 1976) and in acute and chronic patients receiving CPZ (Boullin et al., 19786). Recently, the same research group failed to replicate their earlier results and attributed the discrepancy to differences in patient population (Boullin et al., 1978~). Apart from Boullin’s group, a study from Israel has reported similar results, in which schizophrenic patients with an enhanced platelet aggregation response to 5-HT showed better clinical improvement after 3 weeks of treatment with CPZ (Hefez et al., 1980). Prostaglandin E 1 (PGE I) is known to inhibit platelet aggregation via the 3’,5’-cyclic adenosine monophosphate (CAMP) system (Salzman et al., 1972). Some studies have investigated PGEI function in the platelets of schizophrenic patients. Abdulla and Hamadah (1975) demonstrated that PGEl formation from eicosatrienoic acid, when stimulated with a maximum concentration of adenosine diphosphate (ADP), was almost totally absent in platelets from schizophrenic patients. Rotrosen et al. (1978, 1980) and Kafka et al. (1979) reported a significantly reduced accumulation of PGEl-induced 3H-CAMP formed from AH-adenosine in the platelets of schizophrenic patients when compared to the control group. The present study investigates platelet aggregation response and the inhibitory effect of PGEl on platelet aggregation schizophrenic patients.
to various stimulants response to ADP in
Methods The subjects in this study (see Table I for a description of the sample) received a diagnosis of schizophrenic disorders based on DSM-III criteria (American Psychiatric Association, 1980). Unmedicated patients comprised those cases diagnosed as schizophrenic for the first time or those recurrent cases free from any neuroleptic therapy for at least 3 months before examination. Seven unmedicated patients with reduced platelet sensitivity to epinephrine were included in a weekly followup study after starting neuroleptic medication, and their clinical symptoms were monitored using the Brief Psychiatric Rating Scale (BPRS) of Overall and Gorham (1962). Medicated patients had been continuously treated for at least 3 months with various neuroleptics and antiparkinsonian drugs. To clarify the effects of neuroleptic medication, three normal male volunteers (mean age 26.7 + SD 2.0 years) were examined four times in each 24-hour period after the oral administration of CPZ (50 mg) and three newly diagnosed patients were reexamined I week after starting neuroleptic medication. Nine ml of blood were drawn over a IO- to 13-hour period with a plastic syringe containing 1 ml of 3.8% sodium citrate. Platelet-rich plasma (PRP) was prepared by centrifuging the titrated blood at 15Og, at 10°C for 10 minutes. Platelet-poor plasma was obtained by centrifugation at 15OOg,at 4°C for 10 minutes. Platelet aggregation in response to each stimulant was shown by light transmission (%), using an aggregometer (SIENCO). As stimulants IO-r”-4~10~5 g/ml of epinephrine (EP), 200 @I of dopamine hydrochloride (DA), 50 PRIMof 5-HT, 20 nM-IO PM of ADP, 40 PM-8 mM of arachidonic acid (AA), and 1O-y-1O-5g/ ml of collagen (COL) were added to the PRP, and the maximum light transmission was measured at room temperature. PGE,, 0.5-100 ng,‘ml, was added I minute before determination of platelet aggregation response to
311 Table 1. Normal control and schizophrenic Subjects
n
Platelet aggregation
F
M
Me
subiects SD
Age of onset
SD
response study
Control
18
8
10
32.2
Unmedicated
18
4
14
28.8
7.0
23.4
6.7
Medicated
13
6
7
32.2
12.2
22.2
3.8
Prostaglandin
8.8
study
Control
8
1
7
28.8
4.3
Unmedicated
7
2
5
30.0
5.5
23.7
5.7
Medicated
6
0
6
24.7
6.1
19.8
1.7
The inhibitory effect of PGE I on platelet aggregation response to ADP was represented by decreasing the rate of maximum light transmission %. Student’s 1 test was used for statistical analysis. All data are represented as means *standard deviations. ADP.
Results No differences in platelet aggregation response to 5-HT, DA, COL, or ADP were found among normal control subjects, medicated schizophrenic patients, and unmedicated schizophrenic patients (Table 2). Platelet aggregation response to EP with a concentration of 4x lo-7 g/ml in the unmedicated patients was significantly reduced compared to the control subjects @ < 0.01) (Table 2). In seven of the unmedicated patients, platelet aggregation response to each stimulant was followed weekly for a month after administration of neuroleptic drugs (Fig. I). Significantly increased platelet aggregation response to AA @ < 0.05) was observed after neuroleptic administration began. Clinical ratings on the BPRS correlated well with the minimal concentration required to induce secondary platelet aggregation response to AA (r = 0.94, p < 0.02) during a period of 4 weeks (Fig. I). Clinical improvement also appeared to be correlated with an increase in platelet aggregation response to EP, DA, and 5-HT, but not to a statistically significant degree. Although platelet aggregation response to 2x10-h M of ADP did not differ between normal control subjects and patients with schizophrenia, whether medicated or unmedicated (Table 3) a discrepancy in the inhibitory effect of PGEl on platelet aggregation response between controls and unmedicated patients was seen. Unmedicated patients needed a higher concentration of PGE 1 to inhibit platelet aggregation induced by ADP as compared to normal controls (Table 4, Fig. 2). Sensitivity to PGE 1 in medicated patients was almost equal to that in controls. The acute effects of neuroleptics on the action of PGEl in this study, however, were in the opposite direction of those associated with chronic administration of neuroleptics. The acute administration of neuroleptics diminished the effect of PGEl on platelet aggregation response to ADP in controls (Fig. 3) and in two of three unmedicated patients (Fig. 4) until medication had been given for 7 days.
312 Table
2. Platelet
aggregatory
response
to each
inducer
Aggregation
Inducer
Cont.
%
Unmedicated schizophrenia (n=18)
Control (n=l8)
Medicated schizophrenia (n=13)
50
6.0
i
1.4
8.8
-t
3.9
14.3
?
5.7
200
14.3
2
6.1
a.4
?
4.4
19.7
t
8.2
4X10-8
13.6
-+
6.1
19.4
2
7.6
14.5
i
a.4
rine.
1x10-7
45.9
-+
8.8
45.4
i
8.9
49.8
I!I 11.7
g/ml
2x10-7
68.2
-t
6.8
52.1
i
a.2
74.0
-t
6.8
4x10-7
76.1
+
3.3
54.4
i
7.81
80.3
2
1.4
5-HT, crM
Dopamine,
Epineph-
pM
Arachidonic
1.0
8.8
i
5.1
14.0
-t
7.5
9.8
k
0.8
acid. mM
1.3
27.1
2
a.4
19.4
-t
8.6
18.3
-t
9.9
2.1
63.0
2
7.8
54.5
t
9.6
71.1
t
7.7
4.2
81.3
i
1.3
75.4
i
5.0
79.1
+
1.4
Collagen
1x10-7
11.1
i
5.3
g/ml
2x10-7
33.8
+
a.3
20.9
4x10-7
62.3
!I
6.7
8X10-7
69.4
i
5.8
5x10-7
5.8
i
1X10-6
32.5
+-
2X10-6
76.6
i
2.4
ADP,
M
8.1
-t
5.5
t
6.8
i
7.5
26.0
a.9
2
10.8
48.3
t
7.5
58.1
k
9.8
63.2
2
5.9
71.4
i
3.8
1.7
2.7
i
1.4
5.8
ir
1.7
2.4
27.6
i
6.6
22.3
2
1.8
66.0
t
5.5
80.1
+
1.9
1.~~0.01,compared to controls
Discussion
Although the study sample contained more male than female subjects, no difference in platelet aggregation response attributable to sex was seen. One finding of the study was that unmedicated schizophrenic patients had significantly reduced sensitivity of the platelet aggregation response to EP of higher concentration. It appears that sensitivity of platelet aggregation response to EP depends on the plasma level. Given a high plasma concentration, the receptor of the platelet to the agent becomes hyposensitive and vice versa. In this regard, our patients were expected to show a high plasma level of EP. This speculation is in accord with reported evidence of increased levels of EP in the blood of acute schizophrenic patients (Curtis et al., 1960). A correlation between clinical improvement and increased sensitivity of platelet aggregation response to AA was seen in seven patients with a reduced platelet
13
Fig. 1. Platelet aggregation response (PAR) and clinical ratings after drug treatment in 7 patients with platelet hyposensitivity to epinephrine (EP)
PRs 0
-l
mM .I
0
1
2
3
Q*. ‘\
arachidanic acid
I
0,
BI ‘\
4
!WP
\
s 0
30
3.1
30
20
2.l
20
10
1 .I
0
0
4w
BI !ts NJ/; 0 -30
.\
\ b--_
10
---0 0
b
i
Y \\ \
collagen
;
j
x4
!S 0
2.0
30
20
\
IO
“a-____ 0 O-I,
0
-0 1
2
3
4w
0
I
0
i
1
2
3
3
4w
PAR (black circle and solld liner and Brief Psychlatrlc Rating Scale scores (empty circle and dotted line) are illustrated. PAR to EP, ADP. arachidonic acid, and collagen IS represented as the lowest concentration of the stimulants at which lrreverslble aggregation occurred. Asterisks represent slgniflcantly lowerconcentrations of arachldonvz acid which induced an lrreverslble PAR in comparison with that before medication.
aggregation response to EP. These findings are reminiscent of the results reported by Boullin et al. (1978) and Hefez et al. (1980), who found an association between clinical improvement in neuroleptic-treated patients and an enhanced platelet aggregation response to 5-HT. Further detailed study is needed before it can be concluded that platelet aggregation response to AA is a predictor of drug response. This study on platelet aggregation response to various stimulants revealed neither changes pathognomonic to schizophrenia nor alterations similar to those seen in
314 Table 3. ADP-induced platelet aggregation schizoohrenic oatients and controls
in
Subiects
n
Mean %
SD
Control
8
76.6
9.8
Unmedicated
7
72.5
15.0
Medicated
6
66.0
12.0
Table 4. Effect of PGEl on ADP-induced platelet aggregation in schizophrenic patients and controls (IC 50 of PGEl ng/ml) Mean
SE
8
4.7
1.6
7
36.6
1.6
6
6.1
2.1
Subjects
n
Control Unmedicated’ Medicated 1. pco.001
Fig. 2. Effect of PGEl
1
on ADP-induced
platelet aggregation
O-0
COiltrOl
M
Unmedicated
-
Medicated
patients patients
with with
schizophrenia
schizophrenia
10
100 PC
El
(ng/mll
315 Fig. 3. Influence of chlorpromazine ADP-induced platelet aggregation
on the inhibitory effect of PGEl in 3 normal volunteers
on
80.
40.
20,
OJ ,
0
*
1
p
Fig. 4. Influence of neuroleptics on the effect of PGEl platelet aggregation in acute schizophrenics
days PGEl, 200 ng/ml
on ADP-induced
316 Huntington’s disease, a neurological model of schizophrenia (Kaiya et al., 1980) in which a strong platelet aggregation response to all stimulants was reported (Muramatsu et al., 1982). In the present study, the effects of PGEl in inhibiting platelet aggregation induced by ADP were diminished in unmedicated patients. However, no significant difference in platelet aggregation response to ADP was found among the three groups of subjects (normal controls, medicated and unmedicated schizophrenic patients). Platelet aggregation induced by ADP is associated with CAMP but not with adenylate cyclase; but both agents involve an inhibitory action of PGE I on platelet aggregation (Salzman et al., 1972). It is thought that an aberrant response to PGEl in platelets of patients with schizophrenia may be related to a disturbed PGE I-adenylate cyclase system. The results reported here, which suggest a hyposensitivity of the PGE 1 receptor in platelets from schizophrenic patients, support previous findings of Rotrosen et al. (1978, 1980) and Kafka et al. (1979). Interestingly, these earlier studies, like the present one, found the reduction of platelet aggregation response to PGEl to be more remarkable in unmedicated schizophrenic patients than in medicated ones. There may be a relationship between a reduced platelet aggregation response to EP (possibly related to increased levels of plasma EP) and decreased inhibition of platelet aggregation by PGEl in unmedicated patients with schizophrenia. EP has an inhibitory effect on CAMP formation which is stimulated by PGEl (Kafka et al., 1977). PGEl hyposensitivity in schizophrenia might result from an excess or a deficit of the agent. Reporting higher immunoreactivity of PGE in the cerebrospinal fluid in eight schizophrenic patients, Mathe et al. (1980) suggested that excess PGE lowers PGE sensitivity in platelets. An animal experiment showed that when PGEl-deficient rats were fed a diet lacking in essential fatty acid, inhibition of platelet aggregation by PGEl was reduced (Vincent et al., 1974). In a study of schizophrenic patients, PGE 1 formation in platelets was shown to be significantly decreased (Abdulla and Hamadah, 1975). Thus, we support the viewpoint of Horrobin (1977) that the absence of the PGEl agonist desensitizes the receptor and that a PGEl deficiency may be involved in schizophrenia. Platelets from medicated schizophrenic patients did not show any significant difference in sensitivity to PGE 1 in comparison with normal subjects. However, hyposensitivity of platelets to PGEl was caused by acute treatment with CPZ in three normal volunteers and by various neuroleptics in two of three patients studied. CPZ has been reported to inhibit PG synthesis in vitro (Krupp and West, 1975) and to have no apparent effect on the PGEl-stimulated accumulation of 3H-CAMP in PRP (Rotrosen et al., 1980). Based on this evidence, it is conceivable that antischizophrenic drugs enhance platelet hyposensitivity to PGEl in acute treatment and improve hyposensitivity in chronic treatment. References Abdulla, Y.H., and Hamadah, K. Effect of ADP on PGEI formation in blood platelets from patients with depression, mania and schizophrenia. Brirish Journal qj’Ps,~hiarry, 127, 591 (1975). American Psychiatric Association. DSM-III: Diagnosric and Statistical Manual ~1’ Mental Disorders. 3rd ed. APA. Washington, DC (1980).
317 Besterman, E.M.M., and Gillett, M.P.T. Influence of lysolecithin on platelet aggregation initiated by 5-hydroxytryptamine. Nature, New Biology, 241, 223 (1973). Boullin, D.J., and Grimes, R.P.J. Increased platelet aggregation in patients receiving chlorpromazine: Responses to 5_hydroxytryptamine, dopamine and N-dimethy dopamine. British Journal
of Clinical
Pharmacology,
3, 649 (1976).
Boullin, D.J., Knox, J.M., Peters, J.R., Orr, M.W., Gelder, M.G., and Grahame-Smith, D.G. Platelet aggregation and chlorpromazine therapy. British Journal of Pharmacology, 6, 176 (1978a). Boullin, D.J., Orr, M.W., and Peters, J.R. The platelet as a model for investigating the clinical efficacy of centrally acting drugs: Relations between platelet aggregation and clinical condition in schizophrenics treated with chlorpromazine. In: De Gaetano, G., and Garattini, S., eds. Platelet: A Multidisciplinary Approach. Raven Press, New York, p. 389 (19786). Boullin, D.J., Woods, H.F.. Grimes, R.P.J., and Grahame-Smith, D.G. Increased platelet aggregation responses to 5-hydroxytryptamine in patients taking chlorpromazine. British Journal
of Clinical
Pharmacology.
2, 29 (1975).
Curtis, G.C., Cleghorn, R.A., and Sourkes. T.L. The relationship between affect and the excretion of adrenaline, noradrenaline, and l7-hydroxycorticosteroids. Journal of Psychosomatic Research, 4, 176 (1960). Hefez, A., Oppenheim, B., and Youdim, M.B.H. Human platelet aggregation response to serotonin as an index of efficacy of chlorpromazine. In: Usdin, E., Sourkes, T., and Youdim, M.B.H., eds. Enzymes and Neurotransmitters in Mental Disease. John Wiley & Sons, New York, p. 77 (1980). Horrobin, D.F. Schizophrenia as a prostaglandin deficiency disease. Luncet, 1, 936 (1977). Kafka, M.S., Tallman, J.F., and Smith, C.C. Alpha-adrenergic receptors of human platelets. L$e Sciences, 21, 1429 (1977). Kafka, M.S., Van Kammen, D.P., and Bunney, W.E., Jr. Reduced cyclic AMP production in the blood platelets from schizophrenic patients. American Journal, 136, 685 (1979).
Kaiya, H., Mori, T., Moriuchi, I., Namba, M., Miyagawa, T., and Nakamura, S. Neurotransmitter related agents in the humor of Huntington’s chorea. Japanese Journal of Neuropsychopharmacology, 3, 35 (198 I). Krupp, P., and West, M. Inhibition of prostaglandin synthetase by psychotropic drugs. Experienfia,
31, 330 (1975).
Math& A.A., Sedvall, G., Wiesel, F.A., and Nyb%ck, H. Increased content of immunoreactive prostaglandin E in cerebrospinal fluid of patients with schizophrenia. Lancet, I, I6 (1980). Muramatsu, Y., Kaiya, H., Imai, H.. Nozaki, M., Fujimura, H., and Namba, M. Abnormal platelet aggregation response in Huntington’s disease. Archivfti Psychiatric und Nervenkrankheiten, 232, 19 I (1982). Orr, M.W., and Boullin, D.J. The relationship between changes in 5-HT induced platelet aggregation and clinical state in patients treated with fluphenazine. British Journal of Pharmacolugy,
3. 925 ( 1976).
Overall, J.E., and Gorham, D.R. The Brief Psychiatric Rating Scale. Psychological Reports, 10, 799 (1962). Pletscher, A. Liberation of catecholamines from blood platelets. British JournalqfPharmacolog.,‘, 72, 349 ( 198 I ). Rotrosen. J., Miller, A., Mandio, D.. Traficante, L.J., and Gershon, S. Reduced PGEIstimulated ‘H-CAMP accumulation in platelets from schizophrenics. Lz$e Sciences, 23, 1989
( 1978). Rotrosen, J., Miller, A.D., Mandio, D., Traficante, L.J., and Gershon, S. Prostaglandins, platelets, and schizophrenia. Archives of General Psychiatry. 37, 1047 (1980). Salzman. E.W., Kensler, Levine, L. Cychc
318 Stahl, SM. The human platelet: A diagnostic and research tool for the study of biogenic amines in psychiatric and neurologic disorders. Archives of General Psychiatry, 34, 509 (1977). Vincent, J.E., Melai, A., and Bonta, 1.L. Comparison of the effects of prostaglandin E on platelet aggregation in normal and essential fatty acid deficiency iats. fkwtuglundins. 5,369 (1974).
9, 309-3 I8
309
Platelet Aggregation Prostaglandin El
in Schizophrenia
and
Hisanobu Kaiya, Hirosato Imai, Yayoi Muramatsu, Masakatsu Hajime Fujimura, Soichiro Adachi, and Masuyuki Namba
Nozaki,
Received September 1983.
Response
2, 1983; revised version received Februar_v 2, 1983; accepted February 22,
Abstract. Platelet aggregation response to various stimulants was examined in 18
unmedicated schizophrenic patients, 13 medicated patients, and 13 control subjects. Platelet aggregation response to epinephrine decreased only in unmedicated schizophrenic patients. Clinical improvement in seven patients after neuroleptic medication was significantly correlated with an increase in platelet aggregation response to arachidonic acid, and nonsignificantly to epinephrine, dopamine, and serotonin. The inhibitory effect of prostaglandin El on platelet aggregation response to adenosine diphosphate was investigated in seven unmedicated schizophrenic patients, six medicated patients, and eight controls. The inhibitory effect of prostaglandin E I on platelet aggregation response to adenosine diphosphate was significantly reduced in all unmedicated schizophrenic patients. Neuroleptic medication had some effect in normalizing aberrant sensitivity to prostaglandin E I in those patients, although acute medication induced an adverse reaction in the controls. Key Words. Platelet aggregation
epinephrine,
prostaglandin
response, schizophrenia,
clinical rating scale,
E I.
The platelet is regarded as an excellent tool for the study of biogenic amines and some peptides in psychiatric disorders. Stahl (1977) has reviewed extensively the usefulness and limitations of platelet study as a peripheral model of central nervous system (CNS) monoaminergic neurons. He pointed out that platelets show a greater similarity to serotonergic presynaptic and postsynaptic membranes than to catecholaminergic ones. However, a recent study has shown some evidence suggesting that platelets are also comparable to catecholaminergic neurons (Pletscher, 1981). Therefore, the investigation of platelet aggregation response to various stimulants in schizophrenic patients has aroused considerable interest. The first study of platelet aggregation response in schizophrenia was reported by Boullin et al. (1975), who observed an irreversible platelet aggregation response to serotonin (5-HT) in nine chronic psychiatric patients who were being treated with chlorpromazine (CPZ). The Hisanobu Kaiya. M.D., is Docent, Department of Neuropsychiatry, Gifu University School of Medicine; Hirosato Imai, M.D., and Yayoi Muramatsu are Research Fellows, Department of Pharmacology. Gifu University School of Medicine; Masakatsu Nozaki, Ph.D.. is Docent. Department of Pharmacology, Gifu University School of Medicine; Hajime Fujimura, M.D., is Professor and Chief. Department of Pharmacology, Gifu University School of Medicine; Soichiro Adachi, M.D., is Research Fellow. Department of Neuropaychiatry. Gifu University School of Medicine; and Masuyuki Namba, M.D., is Professor and Chief, Gifu University School of Medicine. (Reprint requests to Dr. H. Kaiya, Department of Neuropsychiatry, Gifu llniversity School of Medicine. Tsukasa-Machi 40. Gifu, Japan.) 0165-1781 ,83 $03.00 0 1983 Elsevier Science Publishers
B.V.
310 incidence of such an irreversible platelet aggregation response in the normal population was reported to be 8% (Besterman and Gillett, 1973). Boullin and Grimes ( 1976) further reported that an enhanced platelet aggregation response in CPZ-treated patients could be induced not only by the administration of 5-HT, but also by dopamine and N-dimethyldopamine. The enhanced platelet aggregation response to 5-HT was associated with clinical improvement in chronic schizophrenic patients receiving fluphenazine decanoate (Orr and Boullin, 1976) and in acute and chronic patients receiving CPZ (Boullin et al., 19786). Recently, the same research group failed to replicate their earlier results and attributed the discrepancy to differences in patient population (Boullin et al., 1978~). Apart from Boullin’s group, a study from Israel has reported similar results, in which schizophrenic patients with an enhanced platelet aggregation response to 5-HT showed better clinical improvement after 3 weeks of treatment with CPZ (Hefez et al., 1980). Prostaglandin E 1 (PGE I) is known to inhibit platelet aggregation via the 3’,5’-cyclic adenosine monophosphate (CAMP) system (Salzman et al., 1972). Some studies have investigated PGEI function in the platelets of schizophrenic patients. Abdulla and Hamadah (1975) demonstrated that PGEl formation from eicosatrienoic acid, when stimulated with a maximum concentration of adenosine diphosphate (ADP), was almost totally absent in platelets from schizophrenic patients. Rotrosen et al. (1978, 1980) and Kafka et al. (1979) reported a significantly reduced accumulation of PGEl-induced 3H-CAMP formed from AH-adenosine in the platelets of schizophrenic patients when compared to the control group. The present study investigates platelet aggregation response and the inhibitory effect of PGEl on platelet aggregation schizophrenic patients.
to various stimulants response to ADP in
Methods The subjects in this study (see Table I for a description of the sample) received a diagnosis of schizophrenic disorders based on DSM-III criteria (American Psychiatric Association, 1980). Unmedicated patients comprised those cases diagnosed as schizophrenic for the first time or those recurrent cases free from any neuroleptic therapy for at least 3 months before examination. Seven unmedicated patients with reduced platelet sensitivity to epinephrine were included in a weekly followup study after starting neuroleptic medication, and their clinical symptoms were monitored using the Brief Psychiatric Rating Scale (BPRS) of Overall and Gorham (1962). Medicated patients had been continuously treated for at least 3 months with various neuroleptics and antiparkinsonian drugs. To clarify the effects of neuroleptic medication, three normal male volunteers (mean age 26.7 + SD 2.0 years) were examined four times in each 24-hour period after the oral administration of CPZ (50 mg) and three newly diagnosed patients were reexamined I week after starting neuroleptic medication. Nine ml of blood were drawn over a IO- to 13-hour period with a plastic syringe containing 1 ml of 3.8% sodium citrate. Platelet-rich plasma (PRP) was prepared by centrifuging the titrated blood at 15Og, at 10°C for 10 minutes. Platelet-poor plasma was obtained by centrifugation at 15OOg,at 4°C for 10 minutes. Platelet aggregation in response to each stimulant was shown by light transmission (%), using an aggregometer (SIENCO). As stimulants IO-r”-4~10~5 g/ml of epinephrine (EP), 200 @I of dopamine hydrochloride (DA), 50 PRIMof 5-HT, 20 nM-IO PM of ADP, 40 PM-8 mM of arachidonic acid (AA), and 1O-y-1O-5g/ ml of collagen (COL) were added to the PRP, and the maximum light transmission was measured at room temperature. PGE,, 0.5-100 ng,‘ml, was added I minute before determination of platelet aggregation response to
311 Table 1. Normal control and schizophrenic Subjects
n
Platelet aggregation
F
M
Me
subiects SD
Age of onset
SD
response study
Control
18
8
10
32.2
Unmedicated
18
4
14
28.8
7.0
23.4
6.7
Medicated
13
6
7
32.2
12.2
22.2
3.8
Prostaglandin
8.8
study
Control
8
1
7
28.8
4.3
Unmedicated
7
2
5
30.0
5.5
23.7
5.7
Medicated
6
0
6
24.7
6.1
19.8
1.7
The inhibitory effect of PGE I on platelet aggregation response to ADP was represented by decreasing the rate of maximum light transmission %. Student’s 1 test was used for statistical analysis. All data are represented as means *standard deviations. ADP.
Results No differences in platelet aggregation response to 5-HT, DA, COL, or ADP were found among normal control subjects, medicated schizophrenic patients, and unmedicated schizophrenic patients (Table 2). Platelet aggregation response to EP with a concentration of 4x lo-7 g/ml in the unmedicated patients was significantly reduced compared to the control subjects @ < 0.01) (Table 2). In seven of the unmedicated patients, platelet aggregation response to each stimulant was followed weekly for a month after administration of neuroleptic drugs (Fig. I). Significantly increased platelet aggregation response to AA @ < 0.05) was observed after neuroleptic administration began. Clinical ratings on the BPRS correlated well with the minimal concentration required to induce secondary platelet aggregation response to AA (r = 0.94, p < 0.02) during a period of 4 weeks (Fig. I). Clinical improvement also appeared to be correlated with an increase in platelet aggregation response to EP, DA, and 5-HT, but not to a statistically significant degree. Although platelet aggregation response to 2x10-h M of ADP did not differ between normal control subjects and patients with schizophrenia, whether medicated or unmedicated (Table 3) a discrepancy in the inhibitory effect of PGEl on platelet aggregation response between controls and unmedicated patients was seen. Unmedicated patients needed a higher concentration of PGE 1 to inhibit platelet aggregation induced by ADP as compared to normal controls (Table 4, Fig. 2). Sensitivity to PGE 1 in medicated patients was almost equal to that in controls. The acute effects of neuroleptics on the action of PGEl in this study, however, were in the opposite direction of those associated with chronic administration of neuroleptics. The acute administration of neuroleptics diminished the effect of PGEl on platelet aggregation response to ADP in controls (Fig. 3) and in two of three unmedicated patients (Fig. 4) until medication had been given for 7 days.
312 Table
2. Platelet
aggregatory
response
to each
inducer
Aggregation
Inducer
Cont.
%
Unmedicated schizophrenia (n=18)
Control (n=l8)
Medicated schizophrenia (n=13)
50
6.0
i
1.4
8.8
-t
3.9
14.3
?
5.7
200
14.3
2
6.1
a.4
?
4.4
19.7
t
8.2
4X10-8
13.6
-+
6.1
19.4
2
7.6
14.5
i
a.4
rine.
1x10-7
45.9
-+
8.8
45.4
i
8.9
49.8
I!I 11.7
g/ml
2x10-7
68.2
-t
6.8
52.1
i
a.2
74.0
-t
6.8
4x10-7
76.1
+
3.3
54.4
i
7.81
80.3
2
1.4
5-HT, crM
Dopamine,
Epineph-
pM
Arachidonic
1.0
8.8
i
5.1
14.0
-t
7.5
9.8
k
0.8
acid. mM
1.3
27.1
2
a.4
19.4
-t
8.6
18.3
-t
9.9
2.1
63.0
2
7.8
54.5
t
9.6
71.1
t
7.7
4.2
81.3
i
1.3
75.4
i
5.0
79.1
+
1.4
Collagen
1x10-7
11.1
i
5.3
g/ml
2x10-7
33.8
+
a.3
20.9
4x10-7
62.3
!I
6.7
8X10-7
69.4
i
5.8
5x10-7
5.8
i
1X10-6
32.5
+-
2X10-6
76.6
i
2.4
ADP,
M
8.1
-t
5.5
t
6.8
i
7.5
26.0
a.9
2
10.8
48.3
t
7.5
58.1
k
9.8
63.2
2
5.9
71.4
i
3.8
1.7
2.7
i
1.4
5.8
ir
1.7
2.4
27.6
i
6.6
22.3
2
1.8
66.0
t
5.5
80.1
+
1.9
1.~~0.01,compared to controls
Discussion
Although the study sample contained more male than female subjects, no difference in platelet aggregation response attributable to sex was seen. One finding of the study was that unmedicated schizophrenic patients had significantly reduced sensitivity of the platelet aggregation response to EP of higher concentration. It appears that sensitivity of platelet aggregation response to EP depends on the plasma level. Given a high plasma concentration, the receptor of the platelet to the agent becomes hyposensitive and vice versa. In this regard, our patients were expected to show a high plasma level of EP. This speculation is in accord with reported evidence of increased levels of EP in the blood of acute schizophrenic patients (Curtis et al., 1960). A correlation between clinical improvement and increased sensitivity of platelet aggregation response to AA was seen in seven patients with a reduced platelet
13
Fig. 1. Platelet aggregation response (PAR) and clinical ratings after drug treatment in 7 patients with platelet hyposensitivity to epinephrine (EP)
PRs 0
-l
mM .I
0
1
2
3
Q*. ‘\
arachidanic acid
I
0,
BI ‘\
4
!WP
\
s 0
30
3.1
30
20
2.l
20
10
1 .I
0
0
4w
BI !ts NJ/; 0 -30
.\
\ b--_
10
---0 0
b
i
Y \\ \
collagen
;
j
x4
!S 0
2.0
30
20
\
IO
“a-____ 0 O-I,
0
-0 1
2
3
4w
0
I
0
i
1
2
3
3
4w
PAR (black circle and solld liner and Brief Psychlatrlc Rating Scale scores (empty circle and dotted line) are illustrated. PAR to EP, ADP. arachidonic acid, and collagen IS represented as the lowest concentration of the stimulants at which lrreverslble aggregation occurred. Asterisks represent slgniflcantly lowerconcentrations of arachldonvz acid which induced an lrreverslble PAR in comparison with that before medication.
aggregation response to EP. These findings are reminiscent of the results reported by Boullin et al. (1978) and Hefez et al. (1980), who found an association between clinical improvement in neuroleptic-treated patients and an enhanced platelet aggregation response to 5-HT. Further detailed study is needed before it can be concluded that platelet aggregation response to AA is a predictor of drug response. This study on platelet aggregation response to various stimulants revealed neither changes pathognomonic to schizophrenia nor alterations similar to those seen in
314 Table 3. ADP-induced platelet aggregation schizoohrenic oatients and controls
in
Subiects
n
Mean %
SD
Control
8
76.6
9.8
Unmedicated
7
72.5
15.0
Medicated
6
66.0
12.0
Table 4. Effect of PGEl on ADP-induced platelet aggregation in schizophrenic patients and controls (IC 50 of PGEl ng/ml) Mean
SE
8
4.7
1.6
7
36.6
1.6
6
6.1
2.1
Subjects
n
Control Unmedicated’ Medicated 1. pco.001
Fig. 2. Effect of PGEl
1
on ADP-induced
platelet aggregation
O-0
COiltrOl
M
Unmedicated
-
Medicated
patients patients
with with
schizophrenia
schizophrenia
10
100 PC
El
(ng/mll
315 Fig. 3. Influence of chlorpromazine ADP-induced platelet aggregation
on the inhibitory effect of PGEl in 3 normal volunteers
on
80.
40.
20,
OJ ,
0
*
1
p
Fig. 4. Influence of neuroleptics on the effect of PGEl platelet aggregation in acute schizophrenics
days PGEl, 200 ng/ml
on ADP-induced
316 Huntington’s disease, a neurological model of schizophrenia (Kaiya et al., 1980) in which a strong platelet aggregation response to all stimulants was reported (Muramatsu et al., 1982). In the present study, the effects of PGEl in inhibiting platelet aggregation induced by ADP were diminished in unmedicated patients. However, no significant difference in platelet aggregation response to ADP was found among the three groups of subjects (normal controls, medicated and unmedicated schizophrenic patients). Platelet aggregation induced by ADP is associated with CAMP but not with adenylate cyclase; but both agents involve an inhibitory action of PGE I on platelet aggregation (Salzman et al., 1972). It is thought that an aberrant response to PGEl in platelets of patients with schizophrenia may be related to a disturbed PGE I-adenylate cyclase system. The results reported here, which suggest a hyposensitivity of the PGE 1 receptor in platelets from schizophrenic patients, support previous findings of Rotrosen et al. (1978, 1980) and Kafka et al. (1979). Interestingly, these earlier studies, like the present one, found the reduction of platelet aggregation response to PGEl to be more remarkable in unmedicated schizophrenic patients than in medicated ones. There may be a relationship between a reduced platelet aggregation response to EP (possibly related to increased levels of plasma EP) and decreased inhibition of platelet aggregation by PGEl in unmedicated patients with schizophrenia. EP has an inhibitory effect on CAMP formation which is stimulated by PGEl (Kafka et al., 1977). PGEl hyposensitivity in schizophrenia might result from an excess or a deficit of the agent. Reporting higher immunoreactivity of PGE in the cerebrospinal fluid in eight schizophrenic patients, Mathe et al. (1980) suggested that excess PGE lowers PGE sensitivity in platelets. An animal experiment showed that when PGEl-deficient rats were fed a diet lacking in essential fatty acid, inhibition of platelet aggregation by PGEl was reduced (Vincent et al., 1974). In a study of schizophrenic patients, PGE 1 formation in platelets was shown to be significantly decreased (Abdulla and Hamadah, 1975). Thus, we support the viewpoint of Horrobin (1977) that the absence of the PGEl agonist desensitizes the receptor and that a PGEl deficiency may be involved in schizophrenia. Platelets from medicated schizophrenic patients did not show any significant difference in sensitivity to PGE 1 in comparison with normal subjects. However, hyposensitivity of platelets to PGEl was caused by acute treatment with CPZ in three normal volunteers and by various neuroleptics in two of three patients studied. CPZ has been reported to inhibit PG synthesis in vitro (Krupp and West, 1975) and to have no apparent effect on the PGEl-stimulated accumulation of 3H-CAMP in PRP (Rotrosen et al., 1980). Based on this evidence, it is conceivable that antischizophrenic drugs enhance platelet hyposensitivity to PGEl in acute treatment and improve hyposensitivity in chronic treatment. References Abdulla, Y.H., and Hamadah, K. Effect of ADP on PGEI formation in blood platelets from patients with depression, mania and schizophrenia. Brirish Journal qj’Ps,~hiarry, 127, 591 (1975). American Psychiatric Association. DSM-III: Diagnosric and Statistical Manual ~1’ Mental Disorders. 3rd ed. APA. Washington, DC (1980).
317 Besterman, E.M.M., and Gillett, M.P.T. Influence of lysolecithin on platelet aggregation initiated by 5-hydroxytryptamine. Nature, New Biology, 241, 223 (1973). Boullin, D.J., and Grimes, R.P.J. Increased platelet aggregation in patients receiving chlorpromazine: Responses to 5_hydroxytryptamine, dopamine and N-dimethy dopamine. British Journal
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Pharmacology,
3, 649 (1976).
Boullin, D.J., Knox, J.M., Peters, J.R., Orr, M.W., Gelder, M.G., and Grahame-Smith, D.G. Platelet aggregation and chlorpromazine therapy. British Journal of Pharmacology, 6, 176 (1978a). Boullin, D.J., Orr, M.W., and Peters, J.R. The platelet as a model for investigating the clinical efficacy of centrally acting drugs: Relations between platelet aggregation and clinical condition in schizophrenics treated with chlorpromazine. In: De Gaetano, G., and Garattini, S., eds. Platelet: A Multidisciplinary Approach. Raven Press, New York, p. 389 (19786). Boullin, D.J., Woods, H.F.. Grimes, R.P.J., and Grahame-Smith, D.G. Increased platelet aggregation responses to 5-hydroxytryptamine in patients taking chlorpromazine. British Journal
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Curtis, G.C., Cleghorn, R.A., and Sourkes. T.L. The relationship between affect and the excretion of adrenaline, noradrenaline, and l7-hydroxycorticosteroids. Journal of Psychosomatic Research, 4, 176 (1960). Hefez, A., Oppenheim, B., and Youdim, M.B.H. Human platelet aggregation response to serotonin as an index of efficacy of chlorpromazine. In: Usdin, E., Sourkes, T., and Youdim, M.B.H., eds. Enzymes and Neurotransmitters in Mental Disease. John Wiley & Sons, New York, p. 77 (1980). Horrobin, D.F. Schizophrenia as a prostaglandin deficiency disease. Luncet, 1, 936 (1977). Kafka, M.S., Tallman, J.F., and Smith, C.C. Alpha-adrenergic receptors of human platelets. L$e Sciences, 21, 1429 (1977). Kafka, M.S., Van Kammen, D.P., and Bunney, W.E., Jr. Reduced cyclic AMP production in the blood platelets from schizophrenic patients. American Journal, 136, 685 (1979).
Kaiya, H., Mori, T., Moriuchi, I., Namba, M., Miyagawa, T., and Nakamura, S. Neurotransmitter related agents in the humor of Huntington’s chorea. Japanese Journal of Neuropsychopharmacology, 3, 35 (198 I). Krupp, P., and West, M. Inhibition of prostaglandin synthetase by psychotropic drugs. Experienfia,
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Overall, J.E., and Gorham, D.R. The Brief Psychiatric Rating Scale. Psychological Reports, 10, 799 (1962). Pletscher, A. Liberation of catecholamines from blood platelets. British JournalqfPharmacolog.,‘, 72, 349 ( 198 I ). Rotrosen. J., Miller, A., Mandio, D.. Traficante, L.J., and Gershon, S. Reduced PGEIstimulated ‘H-CAMP accumulation in platelets from schizophrenics. Lz$e Sciences, 23, 1989
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