- Email: [email protected]
Influence of some neuro-psychotropic drugs on the behavioural modifications induced by 3-acetylpyridine in rats
Prwg.
Vol.
Nemo-Psychopha.
1, PP. 297-300,
1977.
Pergamon Press.
Printed
in Great Britain.
INFLUENCE OF SORE NEURO-PSYCBOTROPICDRUGS ON TRE BERAVIOURAL MODIFICATIONS INDUCED BY 3-ACETYLPYRIDINE IN RATS RENRIETTE FRANCES and P. SIMON Departement de Pharmacologic, Facultl de M6decine Piti&Salp&ri&e, Paris, France (Final
form,
July
1977)
Abstract 1.
2. 3. 4. 5. 6.
3-acetylpyridine, a nicotinamide antimetabolite, administered to rats (65 mg/kg, i.p. route) induced functional disorders: rolling, hypomotility, flatness and "tremors." In an attempt to appreciate the value of this model for previsional psychopharmacology we studied several drugs as possible antagonists of the 3-acetylpyridine-induced symptoms. Amphetamine improved all symptoms except "tremors". Pilocarpine and oxotremorine reduced only rolling. Idrocilamide, baclofene and diazepam decreased only "tremors". The myorelaxant properties of these drugs would represent the basic effect and could be used when screening for a new minor tranquilizer as a simple, rapid and unexpensive test. No effect was observed for the studied doses of L-DOPA, apomorphine, L-SRTP, methysergide, picrotixine and atropine.
Keywords:
3-acetylpyridine,
d-amphetamine,
cholinergic
drugs,
myorelaxants
Introduction The functional disorders induced in rats by a single intraperitoneal injection of 3-acetylpyridine (3-AP), a nicotinamide antimetabolite, consist mainly of a lack of motor co-ordination (Denk et al., 1968; Llinas et at., 1975). The last authors described "sluggished movements, exaggerated flexion of limbs and abnormal shift of body weight from one side to the other". 3-AP induced lesions of the central nervous system in several species including cats, mice and rats. Used in place of nicotinamide in dinucleotide phosphate synthesis, it decreases the rate of enzymic function in which these dinucleotides act as coenzymes (Eerken, 1968). In rats, Desclin and Escubi (1974) observed partial degeneration of the facial and hypoglossal nuclei, almost complete destruction of the nucleus ambiguus and total destruction of the inferior olivery complex. The lack of motor coordination indicating mainly cerebellar dysfunction has been related to the destruction of the Oliver-y complex and of the climbing fibers which arise from this structure and which are the only cerebellar structure destroyed by 3-AP (Denk et aZ., 1968; Desclin and Escubi, 1974). The 3-AP induced symptoms were so manifest a model in previsional psychopharmacology.
that
we decided
to investigate
their
interest
as
Methods Male Wistar (A.F.) rats were obtained from a homogeneous breeding. Their weight varied from 150 to 200 g. at the time of the i.p. injection of 3-AP (65 mg/kg). After 2 weeks, as the symptoms seemed to have reached a steady state, the more affected rats were sorted out to be used in further experiments. In each experiment the rats were separated in 4 groups of two rats. Each group successively received saline and three drugs according to a latin square design with minimal interval of 3 days and in such a manner that an agonist and an antagonist of the same neurotransmitter were not administered in the same experiment. 297
H. Frances
298
and P.. Simon
The rats, taken out of their box, lied on the floor and the symptoms rolling, hypomotility flatness and "tremors" (see Results) were blindly scored from 0 to 3 according to their intensity at 5, 30, 60, 90 and 120 min after the injections. As "tremors" were linked to movemerits, if a rat did not move spontaneously, its displacements had to be induced. All drugs, except ethyl alcohol, were administered (0.5 ml per 100 g body weight) by intraperitoneal route. The following drugs were administered in aqueous solutions: 3-AP, d-amphetamine and atropine sulfates, pilocarpine and apomorphine hydrochlorides, picrotoxine, halooxotremorine and ethyl alcohol. peridoi, The following drugs were administered in aqueous suspension (gum-arabic); methysergide maleate, diazepam idrocilamide, baclofen, i-5HTP and L-DOPA. Results Toxicity
studies
(lethal
effects)
After 3-AP 65 mg/kg i.p. which is the LD50 according to Hicks (1955), we observed thirtyfive deaths out of fifty rats. In force fed rats, the percentage of mortality decreased from seventy to thirty. Mortality was maximal on days 5 and 6; no further death was observed after 2 weeks. 3-acetylpyridine
syndrome
Rats were daily observed. After IO to 15 days the different seemed to have reached a steady state and we decided to score (a) Rolling. When the animal stands, his body shifts he tries to move forward, several lateral revolutions the animal is less affected he stands in dissymmetrical (b)
Hypomotility.
(c) legs
Flatness. wide apart
The spontaneous Animals exhibit and presenting
locomotor
symptoms except the four following
"tremors" symptoms:
from one side to the other, and when of its body may possibly occur. If position.
activity
of the rats
motor weakness. The rat a slight head drop.
lies
flat
is decreased. on ventral
decubitus
with
(d) "Tremors". They occur later (4-6 weeks) and not necessarily among the more affected rats; "tremors" consist of special muscular repetitive jolts appearing when the rat moves forward; they are irregular, slower and wider than the harmaline-induced tremors. Effect
of some neuro-psychotropic
drugs
on 3-AP induced
symptoms
In the following experiments we used only rats clearly affected whose score was 2 or 3 for the different symptoms (approximately 10% of the animals). The results are indicated on Table 1. (a) Amphetamine - Hypomotility Flatness was reduced with kg. modify "tremors".
was the only symptom improved with the lowest 1 and 2 mglkg. This last dose reduced rolling
dose: 0.5 mg/ but did not
(b) Cholinomimetics - Pilocarpine (8 mg/kg) and oxotremorine (0.25 mg/kg) reduced only rolling. Higher pilocarpine dosage (16 mg/kg) increased rolling improvement but was ineffective against other symptoms. "Tremors" and flatness were lightly increased, the latter effect being possibly an attempt to compensate body imbalance. (c) Idrocilamide, baclofen there were no more "tremors". nificantly decreased "tremors" ineffective against the other
and diazepam reduced only "tremors". With 8 mg/kg of baclofen In a different experiment, ethyl alcohol (2 g/kg, orally) sigto 50, 40, 47 X after respectively 30, 60, 120 min. but was symptoms.
Drugs
and
3-acetylpyridine
Table Effects
of
some
drugs
mgikg
i.p.
Amphetamine
Oxotremorine Atropine Idrocilamide Baclofen Diazepam
2 4 2 16 128
Picrotoxine Methysergide L-5HTP
Each result (obtained from expressed as a percentage of when they received saline. score (100%) of - 2.62 f 0.12;
* p < 0.05,
the
rolling 0.5 1 2 0.5 256 0.125 8 16 0.25 4 64 4 8
Apomorphine L-DOPA Haloperidol Pilocarpine
The mean hypomotility
on
Intensity
Dose
**
p < 0.01,
299
1
3-acetylpyridine-induced of the hypomotility
symptoms
symptoms (X of flatness
controls) “tremors”
100 89 54”” 93 107 123 60* 41** 43”” 105 100 104 86
52*** 36”” 25*** 100 115 90 91 95 96 78 95 100 104
76 47” 26*** 76 107 100 106 135 110 112 86 114 126
100 104 118 104 100 109 77 45** 53 o***
129 100 103 104 127
95 115 86 69 90
117 112 105 102 121
22*** 17”” 137 100 100
eight animals) is the control value
eight groups flatness ***
syndrome
of 2.23
the mean score (100X) obtained
eight control f 0.10; and
109 87 129
(30 min. after from the same
rats were: “tremors”-
rolling 2.07 f
administration) eight animals
- 2.34 0.29.
f
0.23;
p < 0.001.
Discussion The similarity Modianos and possible role
of the symptoms Pfaff (1976), after of the qlivo-cerebellar
we observed after 3-AP lesions of the inferior pathways in these
administration olive in dysfunctions.
the
with those rat agrees
described well with
by the
The syndrome induced by 3-AP was, in one way or another, improved by amphetamine, cholinermyorelaxants and ethyl alcohol. The stimulating properties of amphetamine could be gic drugs, but this property did not appear the reason for the improvement of hypomotility and flatness, sufficient to explain the improvement of rolling with the highest dose. “Tremors”were consistently decreased by idrocilamide, baclofen and diazepam as well as by ethyl alcohol. Observation of the animals seems to indicate that these drugs act through their myorelaxant properties. It could be speculated that the site of action of such effect would on catecholaminergic, cholinergic or gabaergic synaptic levels along between lesions and periphery. However, our preliminary results, at permit us to draw definite conclusions. Moreover, such drug-induced from the modified functions of synapses located at unspecified sites. The other tested aggravation with ones, the method From a practical a tranquillizing screening test.
the did
drugs did not improve antagonists of the not permit to know
or
point of view, a myorelaxant
In fact, symptoms. active drugs but the if such an aggravation
the reduction of “tremors” rapid effect as a simple,
be related the pathways the present improvements
to
an action involved time, do not could arise
it would be logical rats used being the occurred. could be used and non expensive
when
to observe more affected
searching complementary
for
an
300
Inquiries
H. Frances
and reprint
requests
Dr. Pierre Simon Ddpartement de Pharmacologic, PitiB-Salp&rilre 91 Bd de 1'liBpital Paris F 75634 Cedex 13 France
should
Facultl
and P. Simon
be addressed
to:
de M6decine
References DENK, II., RRIDER, M., KOVAC, W. und STUDTNKA, G. (1968). VerhaltensPnderung und Neuropathologie bei der 3-Acetylpyridinvergiftung der Ratte. Acta Neuropath. 10: 34-44. DESCLIN, J.C. and ESCUBI, J. (1974). Effects of 3-Acetylpyridine on xe central nervous system of the rat, as demonstrated by silver methods. Brain Res. 77: 349-364. HERKEN, H. (1968). Functional disorders of the brain induced by sshesis of nucleotides containing 3-Acetylpyridine. 5: 349-364. Zeitsch. Klin. Chem. Klin. Biochem. HICKS, S.P. (1955). Pathologic effects of antimetabolites. I. Acute?lesions in the hypothalamus, peripheral ganglia and adrenal medulla caused by 3-acetylpyridine and prevented by nicotinamide. Am. J. Path. 31: 189-197. LLINAS, R., WALTON, K., HILTS D.E. and SOTELO, C. (1975). Inferior olive: Its role in motor learning. Science 190: 1230-1231. MODIANOS, D.T. and PFAFF, Dx (1976). Brainstem and cerebellar lesions in female rats. I. Tests of posture and movement. Bmin Res. -106: 31-46.
Vol.
Nemo-Psychopha.
1, PP. 297-300,
1977.
Pergamon Press.
Printed
in Great Britain.
INFLUENCE OF SORE NEURO-PSYCBOTROPICDRUGS ON TRE BERAVIOURAL MODIFICATIONS INDUCED BY 3-ACETYLPYRIDINE IN RATS RENRIETTE FRANCES and P. SIMON Departement de Pharmacologic, Facultl de M6decine Piti&Salp&ri&e, Paris, France (Final
form,
July
1977)
Abstract 1.
2. 3. 4. 5. 6.
3-acetylpyridine, a nicotinamide antimetabolite, administered to rats (65 mg/kg, i.p. route) induced functional disorders: rolling, hypomotility, flatness and "tremors." In an attempt to appreciate the value of this model for previsional psychopharmacology we studied several drugs as possible antagonists of the 3-acetylpyridine-induced symptoms. Amphetamine improved all symptoms except "tremors". Pilocarpine and oxotremorine reduced only rolling. Idrocilamide, baclofene and diazepam decreased only "tremors". The myorelaxant properties of these drugs would represent the basic effect and could be used when screening for a new minor tranquilizer as a simple, rapid and unexpensive test. No effect was observed for the studied doses of L-DOPA, apomorphine, L-SRTP, methysergide, picrotixine and atropine.
Keywords:
3-acetylpyridine,
d-amphetamine,
cholinergic
drugs,
myorelaxants
Introduction The functional disorders induced in rats by a single intraperitoneal injection of 3-acetylpyridine (3-AP), a nicotinamide antimetabolite, consist mainly of a lack of motor co-ordination (Denk et al., 1968; Llinas et at., 1975). The last authors described "sluggished movements, exaggerated flexion of limbs and abnormal shift of body weight from one side to the other". 3-AP induced lesions of the central nervous system in several species including cats, mice and rats. Used in place of nicotinamide in dinucleotide phosphate synthesis, it decreases the rate of enzymic function in which these dinucleotides act as coenzymes (Eerken, 1968). In rats, Desclin and Escubi (1974) observed partial degeneration of the facial and hypoglossal nuclei, almost complete destruction of the nucleus ambiguus and total destruction of the inferior olivery complex. The lack of motor coordination indicating mainly cerebellar dysfunction has been related to the destruction of the Oliver-y complex and of the climbing fibers which arise from this structure and which are the only cerebellar structure destroyed by 3-AP (Denk et aZ., 1968; Desclin and Escubi, 1974). The 3-AP induced symptoms were so manifest a model in previsional psychopharmacology.
that
we decided
to investigate
their
interest
as
Methods Male Wistar (A.F.) rats were obtained from a homogeneous breeding. Their weight varied from 150 to 200 g. at the time of the i.p. injection of 3-AP (65 mg/kg). After 2 weeks, as the symptoms seemed to have reached a steady state, the more affected rats were sorted out to be used in further experiments. In each experiment the rats were separated in 4 groups of two rats. Each group successively received saline and three drugs according to a latin square design with minimal interval of 3 days and in such a manner that an agonist and an antagonist of the same neurotransmitter were not administered in the same experiment. 297
H. Frances
298
and P.. Simon
The rats, taken out of their box, lied on the floor and the symptoms rolling, hypomotility flatness and "tremors" (see Results) were blindly scored from 0 to 3 according to their intensity at 5, 30, 60, 90 and 120 min after the injections. As "tremors" were linked to movemerits, if a rat did not move spontaneously, its displacements had to be induced. All drugs, except ethyl alcohol, were administered (0.5 ml per 100 g body weight) by intraperitoneal route. The following drugs were administered in aqueous solutions: 3-AP, d-amphetamine and atropine sulfates, pilocarpine and apomorphine hydrochlorides, picrotoxine, halooxotremorine and ethyl alcohol. peridoi, The following drugs were administered in aqueous suspension (gum-arabic); methysergide maleate, diazepam idrocilamide, baclofen, i-5HTP and L-DOPA. Results Toxicity
studies
(lethal
effects)
After 3-AP 65 mg/kg i.p. which is the LD50 according to Hicks (1955), we observed thirtyfive deaths out of fifty rats. In force fed rats, the percentage of mortality decreased from seventy to thirty. Mortality was maximal on days 5 and 6; no further death was observed after 2 weeks. 3-acetylpyridine
syndrome
Rats were daily observed. After IO to 15 days the different seemed to have reached a steady state and we decided to score (a) Rolling. When the animal stands, his body shifts he tries to move forward, several lateral revolutions the animal is less affected he stands in dissymmetrical (b)
Hypomotility.
(c) legs
Flatness. wide apart
The spontaneous Animals exhibit and presenting
locomotor
symptoms except the four following
"tremors" symptoms:
from one side to the other, and when of its body may possibly occur. If position.
activity
of the rats
motor weakness. The rat a slight head drop.
lies
flat
is decreased. on ventral
decubitus
with
(d) "Tremors". They occur later (4-6 weeks) and not necessarily among the more affected rats; "tremors" consist of special muscular repetitive jolts appearing when the rat moves forward; they are irregular, slower and wider than the harmaline-induced tremors. Effect
of some neuro-psychotropic
drugs
on 3-AP induced
symptoms
In the following experiments we used only rats clearly affected whose score was 2 or 3 for the different symptoms (approximately 10% of the animals). The results are indicated on Table 1. (a) Amphetamine - Hypomotility Flatness was reduced with kg. modify "tremors".
was the only symptom improved with the lowest 1 and 2 mglkg. This last dose reduced rolling
dose: 0.5 mg/ but did not
(b) Cholinomimetics - Pilocarpine (8 mg/kg) and oxotremorine (0.25 mg/kg) reduced only rolling. Higher pilocarpine dosage (16 mg/kg) increased rolling improvement but was ineffective against other symptoms. "Tremors" and flatness were lightly increased, the latter effect being possibly an attempt to compensate body imbalance. (c) Idrocilamide, baclofen there were no more "tremors". nificantly decreased "tremors" ineffective against the other
and diazepam reduced only "tremors". With 8 mg/kg of baclofen In a different experiment, ethyl alcohol (2 g/kg, orally) sigto 50, 40, 47 X after respectively 30, 60, 120 min. but was symptoms.
Drugs
and
3-acetylpyridine
Table Effects
of
some
drugs
mgikg
i.p.
Amphetamine
Oxotremorine Atropine Idrocilamide Baclofen Diazepam
2 4 2 16 128
Picrotoxine Methysergide L-5HTP
Each result (obtained from expressed as a percentage of when they received saline. score (100%) of - 2.62 f 0.12;
* p < 0.05,
the
rolling 0.5 1 2 0.5 256 0.125 8 16 0.25 4 64 4 8
Apomorphine L-DOPA Haloperidol Pilocarpine
The mean hypomotility
on
Intensity
Dose
**
p < 0.01,
299
1
3-acetylpyridine-induced of the hypomotility
symptoms
symptoms (X of flatness
controls) “tremors”
100 89 54”” 93 107 123 60* 41** 43”” 105 100 104 86
52*** 36”” 25*** 100 115 90 91 95 96 78 95 100 104
76 47” 26*** 76 107 100 106 135 110 112 86 114 126
100 104 118 104 100 109 77 45** 53 o***
129 100 103 104 127
95 115 86 69 90
117 112 105 102 121
22*** 17”” 137 100 100
eight animals) is the control value
eight groups flatness ***
syndrome
of 2.23
the mean score (100X) obtained
eight control f 0.10; and
109 87 129
(30 min. after from the same
rats were: “tremors”-
rolling 2.07 f
administration) eight animals
- 2.34 0.29.
f
0.23;
p < 0.001.
Discussion The similarity Modianos and possible role
of the symptoms Pfaff (1976), after of the qlivo-cerebellar
we observed after 3-AP lesions of the inferior pathways in these
administration olive in dysfunctions.
the
with those rat agrees
described well with
by the
The syndrome induced by 3-AP was, in one way or another, improved by amphetamine, cholinermyorelaxants and ethyl alcohol. The stimulating properties of amphetamine could be gic drugs, but this property did not appear the reason for the improvement of hypomotility and flatness, sufficient to explain the improvement of rolling with the highest dose. “Tremors”were consistently decreased by idrocilamide, baclofen and diazepam as well as by ethyl alcohol. Observation of the animals seems to indicate that these drugs act through their myorelaxant properties. It could be speculated that the site of action of such effect would on catecholaminergic, cholinergic or gabaergic synaptic levels along between lesions and periphery. However, our preliminary results, at permit us to draw definite conclusions. Moreover, such drug-induced from the modified functions of synapses located at unspecified sites. The other tested aggravation with ones, the method From a practical a tranquillizing screening test.
the did
drugs did not improve antagonists of the not permit to know
or
point of view, a myorelaxant
In fact, symptoms. active drugs but the if such an aggravation
the reduction of “tremors” rapid effect as a simple,
be related the pathways the present improvements
to
an action involved time, do not could arise
it would be logical rats used being the occurred. could be used and non expensive
when
to observe more affected
searching complementary
for
an
300
Inquiries
H. Frances
and reprint
requests
Dr. Pierre Simon Ddpartement de Pharmacologic, PitiB-Salp&rilre 91 Bd de 1'liBpital Paris F 75634 Cedex 13 France
should
Facultl
and P. Simon
be addressed
to:
de M6decine
References DENK, II., RRIDER, M., KOVAC, W. und STUDTNKA, G. (1968). VerhaltensPnderung und Neuropathologie bei der 3-Acetylpyridinvergiftung der Ratte. Acta Neuropath. 10: 34-44. DESCLIN, J.C. and ESCUBI, J. (1974). Effects of 3-Acetylpyridine on xe central nervous system of the rat, as demonstrated by silver methods. Brain Res. 77: 349-364. HERKEN, H. (1968). Functional disorders of the brain induced by sshesis of nucleotides containing 3-Acetylpyridine. 5: 349-364. Zeitsch. Klin. Chem. Klin. Biochem. HICKS, S.P. (1955). Pathologic effects of antimetabolites. I. Acute?lesions in the hypothalamus, peripheral ganglia and adrenal medulla caused by 3-acetylpyridine and prevented by nicotinamide. Am. J. Path. 31: 189-197. LLINAS, R., WALTON, K., HILTS D.E. and SOTELO, C. (1975). Inferior olive: Its role in motor learning. Science 190: 1230-1231. MODIANOS, D.T. and PFAFF, Dx (1976). Brainstem and cerebellar lesions in female rats. I. Tests of posture and movement. Bmin Res. -106: 31-46.