- Email: [email protected]
Effects of synthetic peptides on giant neurons identified in the ganglia of an African giant snail (Achatina fulica Férussac)—III
Camp. Biochem.Physiol.Vol. 87C, No. I, pp. 59-61, 1987 Printedin Great Britain
0
0306-4492/87 $3.00 + 0.00 1987 PergamonJournalsLtd
EFFECTS OF SYNTHETIC PEPTIDES ON GIANT NEURONS IDENTIFIED IN THE GANGLIA OF AN AFRICAN GIANT SNAIL (ACM TINA FULICA FfiRUSSAC)-III KAH HWI KIM, ANCHALEE YONGSIRI, HIROSHI TAKEUCHI,* EISUKE MUNEKATA~
and
NOBORU YANAIHARA,~
YASUO ARIYOSH@
Department of Physiology, Gifu University School of Medicine, Gifu 500, Japan; TLaboratory of Bio-organic Chemistry, Shizuoka College of Pharmacy, Oshika, Shizuoka 422, Japan; SInstitute of Applied Biochemistry, University of Tsukuba, Sakura-mura, Ibaraki 305, Japan; and $Central Research Laboratories, Ajinomoto Co., Inc., Kawasaki 210, Japan (Received 22 July 1986) Abstract-l.
1986, Comp. Biochem. Physiol. 84C, 391-396; peptides, including Metenkephalin, substance P, neurotensin, oxytocin, Arg-vasopressin, proctolin, FMRF-amide and bombesin, on the following identifiable giant neurons of an African giant snail (Achalina fulica Ferussac), were investigated in the present study: TAN-2 (tonically autoactive neuron-2) TAN-3, d-VLN (dorsal-visceral large neuron), FAN (frequently autoactive neuron), d-RPeAN (dorsal-right pedal autoactive neuron) in the suboesophageal ganglia; and V-RCDN (ventral-right cerebral distinct neuron) and V-LCDN (ventralleft cerebral distinct neuron) in the cerebral ganglia. 2. Of the peptides examined, oxytocin at 10-4M showed slight excitatory effects on V-LCDN, the same effects sometimes on d-VLN, and slight inhibitory effects on TAN-2. FMRF-amide at the same concentration produced the TAN-2 inhibition. The other peptides examined showed no effect on the neurons mentioned. 3. Neurons other than those mentioned (i.e. TAN-3, FAN, d-RPeAN and V-RCDN) were insensitive to all of the peptides examined. Following
previous
reports
(Ku
ef al.,
Yongsiri er al., 1987, Comp. Biochem. Physiol. in press), the effects of synthetic
INTRODUCTION
were synthesized in and Arg-vasopressin Osaka). The peptides 10e4 M in the snail’s 1973), and applied perfusion (Ku et al.,
Previous studies (Ku et al., 1986; Anchalee et al., 1987) reported the effects of 13 biologically-active peptides, including Met-enkephalin, substance P, neurotensin, oxytocin, Arg-vasopressin, proctolin, FMRF-amide and bombesin, on a total of 11 identifiable giant neurons of an African giant snail (Achafina fulica Ferussac). The effects of the same peptides on seven identifiable Achatina neurons, other than the neurons tested previously, were investigated in the present study.
RESULTS
The results obtained are summarized in Table 1. Of the peptides examined, oxytocin and FMRF-amide displayed effects on some neurons among those tested in the present study. Figure 1 shows the effects of oxytocin and FMRFamide on the four giant neurons: TAN-2, TAN-3, d-VLN and V-LCDN. Of these, TAN-2 and TAN-3 had spontaneous spike discharges, whereas d-VLN and V-LCDN did not. The two peptides mentioned caused short-lasting inhibitions of TAN-2 (Fig. 1, A and B). The TAN-2 membrane potential was inhibited by the application of FMRF-amide at 10m4M, resulting in a transient stop of the spike discharges. However, the inhibition of the neuron caused by oxytocin at 10m4M was so slight that the spike discharges remained during the application of the peptide. On the other hand, TAN-3 was insensitive to the two peptides at the same concentration (C and D). A silent neuron, d-VLN, was sometimes excited by oxytocin at 10m4M, resulting in the production of spike discharges (E). However, the neuron was not always affected by the same peptide. Another silent
MATERIALS AND METHODS
An African giant snail (Achafina jiulica Ftrussac) was flown in from Manila (Philippines). The identifiable giant neurons of the snail used in the present experiments were as follows: TAN-2 (tonicallv autoactive neuron-2). TAN-3, d-VLN (dorsal-visceral large neuron), FAN (frequently autoactive neuron) and d-RPeAN (dorsal-pedal autoactive neuron) in the suboesophageal ganglia; and V-RCDN (ventral-right cerebral distinct neuron) and V-LCDN (ventral-left cerebral distinct neuron) in the cerebral ganglia (Takeuchi and Yamamoto, 1982; Ku and Takeuchi, 1983, 1985; Boyles and Takeuchi, 1985; Goto e! al., 1986; Matsuoka et al., 1986; Yongsiri et al., 1986). The giant neurons tested were completely denuded by removing the connective tissue, which covered the neurons, after trypsin treatment according to Sun’s method (Sun and Takeuchi, 1986). The peptides examined, listed in Table 1,
*Author
to whom
correspondence
should
our laboratories except for oxytocin (products of Peptide Institute, Inc, in were dissolved at a concentration of physiological solution (Takeuchi et al., to the dissected ganglia by way of 1986).
be addressed. 59
KAH HWI KIM et al.
60 Table I. Effects of synthetic biologically-active
NO.
Substances
1. Peptides proposed I Met-enkephalin 2. Substance P 3. Neurotensin 4. LH-RH 5. [Gin”]-LH-RH 6. Oxytocin 7. Arg-vasopressin II. Peptides proposed 8. Proctolin 9. FMRF-amide
Effects on TAN-2 as neurotransmitters (-_) (-_) (-_) (-_) (-_)
E, Excitatory
(-_) (-_) (-_) (-_)
effects. I, Inhibitory
Ftrussac)
Effects on d-VLN
Effects on FAN
Effects on d-RPeAN
Effects on V-RCDN
Effects on V-LCDN
(-_) (-_) (-_) (-_) (-_) SE or (-_) (-_)
(-_)
(-_) (-_) (-_) (-_)
(-_) (-_) (-_) (-_) (-_) (-_) (-_)
(-_) (-_) (-_) (-_) (-_) (-_) (-_)
(-_) (-_) (-_) (-_) (-_)
in invertebrates (-_) (-_)
(-_)
(-_)
(6_)
(-_)
c-1
(-_)
;I;
(-_) (-_) (-_) (-1
(-1 (-_) (-_) (-_)
(-_) (-_) (-_) (-_)
(-_) (-_) (-_) (-_)
in mammals (-_)
(-_) (-_) (-) (-_)
(“I,
111. Natural venom peptides IO. Bombesin I I. Ranatensin C 12. Vespakinin X 13. Vespakinin M
Effects on TAN-3
17;
as neurotransmitters (-_)
I
pepttdes on giant neurons of an African giant snail (Achnrina /i/ica (screening tests at 10m4M)
effects. SE, Slightly
17;
;I; (-_) (-_)
excitatory
effects. SI, Slightly
inhibitory
z (-_)
(-_) (-_) (-_) (-_) (-_)
effects. (-_). No effect.
TAN-2
110e4M
Oxytocin
A IO-'M
FMRF-amide
TAN-3
i 10m4M Oxytocin
;t 10°4M FMRF-amide
d-VLN
E---_--1.-:3-~~rJ~~ 10 4M
Oxytocin
V-LCDN
Fig.
1
E&t
of peptides on snail neurons
neuron, V-LCDN, was excited by oxytocin at 10e4 M, so that spike discharges were produced (F). By the application of oxytocin, a marked augmentation of the synaptic influences arriving at the V-LCDN membrane potential was also observed. The neurons tested other than those mentioned above (i.e. FAN, d-RPeAN and V-RCDN), were insensitive to all of the peptides examined.
DISCUSSION
The previous reports (Ku et al., 1986; Yongsiri et al., 1987) demonstrated that oxytocin produced excitatory effects on four neurons tested, PON (periodically oscillating neuron), d-RPLN (dorsalright parietal large neuron), VIN (visceral intermittently firing neuron) and RAPN (right anterior pa&al neuron), out of 11 identifiable neurons of Achatina jiulica Ferussac. In the present study, slight inhibitory effects of oxytocin were observed on TAN-2, the first case of an inhibition caused by this peptide. Matsuoka et al. (1986) reported that three giant neurons identified in the right parietal ganglion in the suboesophageal ganglia, TAN, TAN-2 and TAN-3, were analogous with respect to axonal pathways and pha~acological features, especially as to the putative neurotransmitters of amines, amino acids and acetylcholine. Two of the three analogous neurons, TAN (Ku et al., 1986) and TAN-2, were inhibited by FMRF-amide, whereas only TAN-3 was insensitive to it. On the dorsal surface of the suboesophageal ganglia, the two largest neurons, d-RPLN (dorsal-right parietal large neuron) and d-VLN, are symmetrically situated. The axonal pathways of the two neurons are also reported to be symnmetrical (Goto et al., 1986); their sensitivities to amine, amino acids and acetylcholine were almost identical (Takeuchi and Yamamoto, 1982). It was found that d-RPLN was excited by oxytocin (Ku et al., 1986). d-VLN was also found to be excited by the same peptide, though the effects of d-VLN were weaker than those on d-RPLN. On the ventral surface of the cerebral ganglia, two neurons, V-RCDN and V-LCDN, were found to be symmetrically located. The axonal pathways of these two neurons were also symmetrical (Yongsiri et al., 1986); their sensitivities to amines, amino acids, etc. were identical. However, V-LCDN was slightly excited by oxytocin, whereas V-RCDN was insensitive to it.
Physiology and Medicine, and by a Grant-in-Aid (Special Project to Gifu University in 1984 and 1985) from the Ministry of Education and Culture of Japan.
REFERENCES
Boyles H. P. and Takeuchi H. (1985) Pharmacological characteristics of the three giant neurones, d-LPeLN, d-LPeCN and d-RPeAN, identified on the dorsal surface of the pedal ganglia of an African giant snail (Acharina ,fulica Fetus&). totnp. Biochem. Physiol. 81C,‘lO9-115. Goto T., Ku B. S. and Takeuchi H. (1986) Axonal oathwavs of the giant neurones identi~e~ in the right’and left parietai and visceral ganglia of an African giant snail (Achatina,fulica Ferussac). Camp. Biochem. Physiol. 83A, 93-104. Ku B. S., Isobe K. and Takeuchi H. (1985) Pharmacological
characteristics of four giant neurones identified in the cerebral ganglia of an African giant snail (Achat~ffu,~u~jca Ferussac). Camp. Biochem. Physiol. 8OC, 123-128. Ku B. S. and Takeuchi H. (1983) Identification of three further giant neurones. r-APN, INN and FAN, in the caudai part on the dorsal surface of the suboesophageal ganglia of Achatina firlica Ferussac. Contp. Biochem. Physioi. 76C, 99- IO6 Ku B. S., Takeuchi H., Yanaihara N., Munekata E. and Ariyoshi N. (1986) Effects of synthetic peptides on giant neurones identified in the ganglia of an African giant snail (Achatina,~u~ica Ferussac). Comp. Biochem. Physid. SK, 391-396.
Matsuoka T., Goto T., Watanabe K. and Takeuchi H. (1986) Presence of TAN (tonically autoactive neurone) and its two analogous neurones, located in the right parietal ganglion of the suboesophageal ganglia of an African giant snail (Achatina fulica Ferussac). Morphological and electrophysiological studies. Camp. Biochem. Physiol. 83C, 345-35 1. Sun X. P. and Takeuchi H. (1986) Decrease of action
potentiaf amplitudes, in sodium-free and calcium-free conditions, of identified giant neurones of an African giant snail (Achatina fulica Ferussac)-I. The right parietal ganglion. Camp. Biochem. Physiol. 84A, 19-24. Takeuchi H.. Morimasa T., Kohsaka M., Kobayashi J. and Morii F. (1973) Con~ntrations des ions inorganiques dans I’hemolymphe de 1’Escargot @ant africain (Achatina fulica F&usSx) selon fitat de nutrition. C.r. SPanc. Sot. Biol. 167, 598-602. Takeuchi H. and Yamamoto N. (1982) Pharmacological characteristics of the two largest neurones symmetrically situated in the suboesophageal ganglia of an African giant snail (Achatina fulica Ferussac). Camp. Biochem. Physiol. 73C, 339-346.
Yongsiri A., Goto T., Yamamoto N., Araki Y., Takeuchi H. and Namba M. (1986) Axonal pathways of the four giant neurones identified in the cerebral ganglia of an African giant snail (Achatina fulica Ferussac). Camp. Biochem.
Acknowledgemenfs-The authors wish to express their thanks to Mr Juan&o E. Gementiza of Beigor Investment. Inc. in Manila, for providing the African giant snails (Achatina fulica Ferussac). This work was supported in part by the Professor Kato Memorial Research Fund for
61
Physiol. 85A, 663-668.
Yongsiri A., Kim K. H., Takeuchi H., Yanaihara N., Munekata E. and Ariyoshi N. (1987) Effects of synthetic peptides on giant neurones identified in the ganglia of an African giant snail (Achatinafulica Ftrussac)-II. Camp. Biochem.
Physiol. 86C, 353-356.
Fig. 1. Effects of the peptides on the membrane potentials of TAN-2 (tonically autoactive neuron-2). TAN-3, d-VLN (dorsal-ventral large neuron) and V-LCDN (ventral-left cerebral distinct neuron). The spike heights were cut el~troni~l~y. The effects of oxytocin (A) and FMR~-amide (Bf at 10e4M on TAN-2, oxytocin (C) and FMRF-amide (D) at 10s4 M on TANJ, and oxytocin at 1O-4 M on d-VLN (E) and V-LCDN (F), were respectively examined, Arrows indicate the application of the peptides. Vertical bar, calibration (20 mV). Horizontal bar, time course (30 set).
0
0306-4492/87 $3.00 + 0.00 1987 PergamonJournalsLtd
EFFECTS OF SYNTHETIC PEPTIDES ON GIANT NEURONS IDENTIFIED IN THE GANGLIA OF AN AFRICAN GIANT SNAIL (ACM TINA FULICA FfiRUSSAC)-III KAH HWI KIM, ANCHALEE YONGSIRI, HIROSHI TAKEUCHI,* EISUKE MUNEKATA~
and
NOBORU YANAIHARA,~
YASUO ARIYOSH@
Department of Physiology, Gifu University School of Medicine, Gifu 500, Japan; TLaboratory of Bio-organic Chemistry, Shizuoka College of Pharmacy, Oshika, Shizuoka 422, Japan; SInstitute of Applied Biochemistry, University of Tsukuba, Sakura-mura, Ibaraki 305, Japan; and $Central Research Laboratories, Ajinomoto Co., Inc., Kawasaki 210, Japan (Received 22 July 1986) Abstract-l.
1986, Comp. Biochem. Physiol. 84C, 391-396; peptides, including Metenkephalin, substance P, neurotensin, oxytocin, Arg-vasopressin, proctolin, FMRF-amide and bombesin, on the following identifiable giant neurons of an African giant snail (Achalina fulica Ferussac), were investigated in the present study: TAN-2 (tonically autoactive neuron-2) TAN-3, d-VLN (dorsal-visceral large neuron), FAN (frequently autoactive neuron), d-RPeAN (dorsal-right pedal autoactive neuron) in the suboesophageal ganglia; and V-RCDN (ventral-right cerebral distinct neuron) and V-LCDN (ventralleft cerebral distinct neuron) in the cerebral ganglia. 2. Of the peptides examined, oxytocin at 10-4M showed slight excitatory effects on V-LCDN, the same effects sometimes on d-VLN, and slight inhibitory effects on TAN-2. FMRF-amide at the same concentration produced the TAN-2 inhibition. The other peptides examined showed no effect on the neurons mentioned. 3. Neurons other than those mentioned (i.e. TAN-3, FAN, d-RPeAN and V-RCDN) were insensitive to all of the peptides examined. Following
previous
reports
(Ku
ef al.,
Yongsiri er al., 1987, Comp. Biochem. Physiol. in press), the effects of synthetic
INTRODUCTION
were synthesized in and Arg-vasopressin Osaka). The peptides 10e4 M in the snail’s 1973), and applied perfusion (Ku et al.,
Previous studies (Ku et al., 1986; Anchalee et al., 1987) reported the effects of 13 biologically-active peptides, including Met-enkephalin, substance P, neurotensin, oxytocin, Arg-vasopressin, proctolin, FMRF-amide and bombesin, on a total of 11 identifiable giant neurons of an African giant snail (Achafina fulica Ferussac). The effects of the same peptides on seven identifiable Achatina neurons, other than the neurons tested previously, were investigated in the present study.
RESULTS
The results obtained are summarized in Table 1. Of the peptides examined, oxytocin and FMRF-amide displayed effects on some neurons among those tested in the present study. Figure 1 shows the effects of oxytocin and FMRFamide on the four giant neurons: TAN-2, TAN-3, d-VLN and V-LCDN. Of these, TAN-2 and TAN-3 had spontaneous spike discharges, whereas d-VLN and V-LCDN did not. The two peptides mentioned caused short-lasting inhibitions of TAN-2 (Fig. 1, A and B). The TAN-2 membrane potential was inhibited by the application of FMRF-amide at 10m4M, resulting in a transient stop of the spike discharges. However, the inhibition of the neuron caused by oxytocin at 10m4M was so slight that the spike discharges remained during the application of the peptide. On the other hand, TAN-3 was insensitive to the two peptides at the same concentration (C and D). A silent neuron, d-VLN, was sometimes excited by oxytocin at 10m4M, resulting in the production of spike discharges (E). However, the neuron was not always affected by the same peptide. Another silent
MATERIALS AND METHODS
An African giant snail (Achafina jiulica Ftrussac) was flown in from Manila (Philippines). The identifiable giant neurons of the snail used in the present experiments were as follows: TAN-2 (tonicallv autoactive neuron-2). TAN-3, d-VLN (dorsal-visceral large neuron), FAN (frequently autoactive neuron) and d-RPeAN (dorsal-pedal autoactive neuron) in the suboesophageal ganglia; and V-RCDN (ventral-right cerebral distinct neuron) and V-LCDN (ventral-left cerebral distinct neuron) in the cerebral ganglia (Takeuchi and Yamamoto, 1982; Ku and Takeuchi, 1983, 1985; Boyles and Takeuchi, 1985; Goto e! al., 1986; Matsuoka et al., 1986; Yongsiri et al., 1986). The giant neurons tested were completely denuded by removing the connective tissue, which covered the neurons, after trypsin treatment according to Sun’s method (Sun and Takeuchi, 1986). The peptides examined, listed in Table 1,
*Author
to whom
correspondence
should
our laboratories except for oxytocin (products of Peptide Institute, Inc, in were dissolved at a concentration of physiological solution (Takeuchi et al., to the dissected ganglia by way of 1986).
be addressed. 59
KAH HWI KIM et al.
60 Table I. Effects of synthetic biologically-active
NO.
Substances
1. Peptides proposed I Met-enkephalin 2. Substance P 3. Neurotensin 4. LH-RH 5. [Gin”]-LH-RH 6. Oxytocin 7. Arg-vasopressin II. Peptides proposed 8. Proctolin 9. FMRF-amide
Effects on TAN-2 as neurotransmitters (-_) (-_) (-_) (-_) (-_)
E, Excitatory
(-_) (-_) (-_) (-_)
effects. I, Inhibitory
Ftrussac)
Effects on d-VLN
Effects on FAN
Effects on d-RPeAN
Effects on V-RCDN
Effects on V-LCDN
(-_) (-_) (-_) (-_) (-_) SE or (-_) (-_)
(-_)
(-_) (-_) (-_) (-_)
(-_) (-_) (-_) (-_) (-_) (-_) (-_)
(-_) (-_) (-_) (-_) (-_) (-_) (-_)
(-_) (-_) (-_) (-_) (-_)
in invertebrates (-_) (-_)
(-_)
(-_)
(6_)
(-_)
c-1
(-_)
;I;
(-_) (-_) (-_) (-1
(-1 (-_) (-_) (-_)
(-_) (-_) (-_) (-_)
(-_) (-_) (-_) (-_)
in mammals (-_)
(-_) (-_) (-) (-_)
(“I,
111. Natural venom peptides IO. Bombesin I I. Ranatensin C 12. Vespakinin X 13. Vespakinin M
Effects on TAN-3
17;
as neurotransmitters (-_)
I
pepttdes on giant neurons of an African giant snail (Achnrina /i/ica (screening tests at 10m4M)
effects. SE, Slightly
17;
;I; (-_) (-_)
excitatory
effects. SI, Slightly
inhibitory
z (-_)
(-_) (-_) (-_) (-_) (-_)
effects. (-_). No effect.
TAN-2
110e4M
Oxytocin
A IO-'M
FMRF-amide
TAN-3
i 10m4M Oxytocin
;t 10°4M FMRF-amide
d-VLN
E---_--1.-:3-~~rJ~~ 10 4M
Oxytocin
V-LCDN
Fig.
1
E&t
of peptides on snail neurons
neuron, V-LCDN, was excited by oxytocin at 10e4 M, so that spike discharges were produced (F). By the application of oxytocin, a marked augmentation of the synaptic influences arriving at the V-LCDN membrane potential was also observed. The neurons tested other than those mentioned above (i.e. FAN, d-RPeAN and V-RCDN), were insensitive to all of the peptides examined.
DISCUSSION
The previous reports (Ku et al., 1986; Yongsiri et al., 1987) demonstrated that oxytocin produced excitatory effects on four neurons tested, PON (periodically oscillating neuron), d-RPLN (dorsalright parietal large neuron), VIN (visceral intermittently firing neuron) and RAPN (right anterior pa&al neuron), out of 11 identifiable neurons of Achatina jiulica Ferussac. In the present study, slight inhibitory effects of oxytocin were observed on TAN-2, the first case of an inhibition caused by this peptide. Matsuoka et al. (1986) reported that three giant neurons identified in the right parietal ganglion in the suboesophageal ganglia, TAN, TAN-2 and TAN-3, were analogous with respect to axonal pathways and pha~acological features, especially as to the putative neurotransmitters of amines, amino acids and acetylcholine. Two of the three analogous neurons, TAN (Ku et al., 1986) and TAN-2, were inhibited by FMRF-amide, whereas only TAN-3 was insensitive to it. On the dorsal surface of the suboesophageal ganglia, the two largest neurons, d-RPLN (dorsal-right parietal large neuron) and d-VLN, are symmetrically situated. The axonal pathways of the two neurons are also reported to be symnmetrical (Goto et al., 1986); their sensitivities to amine, amino acids and acetylcholine were almost identical (Takeuchi and Yamamoto, 1982). It was found that d-RPLN was excited by oxytocin (Ku et al., 1986). d-VLN was also found to be excited by the same peptide, though the effects of d-VLN were weaker than those on d-RPLN. On the ventral surface of the cerebral ganglia, two neurons, V-RCDN and V-LCDN, were found to be symmetrically located. The axonal pathways of these two neurons were also symmetrical (Yongsiri et al., 1986); their sensitivities to amines, amino acids, etc. were identical. However, V-LCDN was slightly excited by oxytocin, whereas V-RCDN was insensitive to it.
Physiology and Medicine, and by a Grant-in-Aid (Special Project to Gifu University in 1984 and 1985) from the Ministry of Education and Culture of Japan.
REFERENCES
Boyles H. P. and Takeuchi H. (1985) Pharmacological characteristics of the three giant neurones, d-LPeLN, d-LPeCN and d-RPeAN, identified on the dorsal surface of the pedal ganglia of an African giant snail (Acharina ,fulica Fetus&). totnp. Biochem. Physiol. 81C,‘lO9-115. Goto T., Ku B. S. and Takeuchi H. (1986) Axonal oathwavs of the giant neurones identi~e~ in the right’and left parietai and visceral ganglia of an African giant snail (Achatina,fulica Ferussac). Camp. Biochem. Physiol. 83A, 93-104. Ku B. S., Isobe K. and Takeuchi H. (1985) Pharmacological
characteristics of four giant neurones identified in the cerebral ganglia of an African giant snail (Achat~ffu,~u~jca Ferussac). Camp. Biochem. Physiol. 8OC, 123-128. Ku B. S. and Takeuchi H. (1983) Identification of three further giant neurones. r-APN, INN and FAN, in the caudai part on the dorsal surface of the suboesophageal ganglia of Achatina firlica Ferussac. Contp. Biochem. Physioi. 76C, 99- IO6 Ku B. S., Takeuchi H., Yanaihara N., Munekata E. and Ariyoshi N. (1986) Effects of synthetic peptides on giant neurones identified in the ganglia of an African giant snail (Achatina,~u~ica Ferussac). Comp. Biochem. Physid. SK, 391-396.
Matsuoka T., Goto T., Watanabe K. and Takeuchi H. (1986) Presence of TAN (tonically autoactive neurone) and its two analogous neurones, located in the right parietal ganglion of the suboesophageal ganglia of an African giant snail (Achatina fulica Ferussac). Morphological and electrophysiological studies. Camp. Biochem. Physiol. 83C, 345-35 1. Sun X. P. and Takeuchi H. (1986) Decrease of action
potentiaf amplitudes, in sodium-free and calcium-free conditions, of identified giant neurones of an African giant snail (Achatina fulica Ferussac)-I. The right parietal ganglion. Camp. Biochem. Physiol. 84A, 19-24. Takeuchi H.. Morimasa T., Kohsaka M., Kobayashi J. and Morii F. (1973) Con~ntrations des ions inorganiques dans I’hemolymphe de 1’Escargot @ant africain (Achatina fulica F&usSx) selon fitat de nutrition. C.r. SPanc. Sot. Biol. 167, 598-602. Takeuchi H. and Yamamoto N. (1982) Pharmacological characteristics of the two largest neurones symmetrically situated in the suboesophageal ganglia of an African giant snail (Achatina fulica Ferussac). Camp. Biochem. Physiol. 73C, 339-346.
Yongsiri A., Goto T., Yamamoto N., Araki Y., Takeuchi H. and Namba M. (1986) Axonal pathways of the four giant neurones identified in the cerebral ganglia of an African giant snail (Achatina fulica Ferussac). Camp. Biochem.
Acknowledgemenfs-The authors wish to express their thanks to Mr Juan&o E. Gementiza of Beigor Investment. Inc. in Manila, for providing the African giant snails (Achatina fulica Ferussac). This work was supported in part by the Professor Kato Memorial Research Fund for
61
Physiol. 85A, 663-668.
Yongsiri A., Kim K. H., Takeuchi H., Yanaihara N., Munekata E. and Ariyoshi N. (1987) Effects of synthetic peptides on giant neurones identified in the ganglia of an African giant snail (Achatinafulica Ftrussac)-II. Camp. Biochem.
Physiol. 86C, 353-356.
Fig. 1. Effects of the peptides on the membrane potentials of TAN-2 (tonically autoactive neuron-2). TAN-3, d-VLN (dorsal-ventral large neuron) and V-LCDN (ventral-left cerebral distinct neuron). The spike heights were cut el~troni~l~y. The effects of oxytocin (A) and FMR~-amide (Bf at 10e4M on TAN-2, oxytocin (C) and FMRF-amide (D) at 10s4 M on TANJ, and oxytocin at 1O-4 M on d-VLN (E) and V-LCDN (F), were respectively examined, Arrows indicate the application of the peptides. Vertical bar, calibration (20 mV). Horizontal bar, time course (30 set).