Peptidergic inhibition of cholinergic transmission in bullfrog sympathetic ganglia.

Hasuo, Hiroshi; Akasu, Takashi

doi:10.2170/jjphysiol.38.643

Cited by 4 publications

(2 citation statements)

References 38 publications

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“…However, it has also been shown that the fast EPSP of B neurons is depressed during the late slow EPSP by decrease of ACh release from preganglionic endings (Hasuo and Akasu, 1988). Ionic mechanisms of receptor activation in amphibian ganglia have been extensively reviewed by Smith (1994).…”

Section: Principal Neurons and Their Synapsesmentioning

confidence: 99%

Synaptic organization of amphibian sympathetic ganglia

Lascar

Eugène

Taxi

1996

Microsc. Res. Tech.

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The synaptic organization of the amphibian sympathetic ganglia was studied, especially in the last two abdominal paravertebral ganglia of the frog. These ganglia appear to form a monosynaptic relay, not containing interneurons. They consist of two systems working in parallel: the principal neurons, by far the most numerous, and a small number of chromaffin (i.e., SIF) cells, usually arranged in clusters. Each principal neuron is innervated by a preganglionic branch forming a set of cholinergic synapses which exhibit classical ultrastucture. The only peculiarity is the presence of a subsynaptic apparatus in a variable percentage of synaptic complexes. Electro‐physiological studies have demonstrated that synaptic transmission is due to ACh release and involves several postsynaptic potentials. Moreover, the principal neurons are of two types, B and C, whose preganglionic axons and their own axons have different conduction velocities. C neurons tend to be small in diameter, and B neurons are larger, but the size distribution of the two populations overlaps. More recently, it was demonstrated that these two neuronal systems have different immunocytochemical features. The C preganglionic fibers contain an LHRH‐like peptide, which is responsible for late synaptic events. The B preganglionic fibers contain CGRP, whose role has not yet been established. The principal neurons all contain adrenaline, but neuropeptide Y is also present in C neurons and could be a second transmitter at peripheral junctions. SP‐containing fibers also pass through the ganglia, but give rise to intraganglionic synapses only rarely, except in the celiac plexus. Galanin can coexist with neuropeptide Y in certain C neurons. Numerous principal neurons are immunoreactive for VIP. Chromaffin cells contain noradrenaline and metenkephalin, and some contain SP or LHRH; they are endocrine cells controlled by preganglionic fibers and can have a modulatory effect on principal neurons endowed with appropriate receptors. The accessibility of frog abdominal ganglia and the anatomical separation of B and C preganglionic fiber pathways provide interesting systems in which to carry out experimentation on the stability and specificity of synaptic contacts. After postganglionic axotomy, the majority of synapses disappear by disruption of synaptic contacts. There is a certain discrepancy between the recovery of synaptic transmission and the reappearance of morphologically identifiable synapses, suggesting that a certain amount of transmission is possible at contacts devoid of synaptic complexes. The selective deafferentation of B or C neurons showed that the subsynaptic apparati are mainly found at B neuron synapses. The course of reinnervation following selective deafferentation reveals the existence of different specificities at B and C synapses: C neurons are easily reinnervated by B preganglionic fibers, whereas C fibers appear fairly ineffective at reinnervating B neurons, even after a long interval. Attempts were made to reinnervate ganglionic neurons...

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Section: Principal Neurons and Their Synapsesmentioning

confidence: 99%

Synaptic organization of amphibian sympathetic ganglia

Lascar

Eugène

Taxi

1996

Microsc. Res. Tech.

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“…whereas the slow IPSPs are not able to block it, but only to prevent repetitive discharge in C neurons (Dodd and Horn, 1983b). However, it has also been shown that the fast EPSP of B neurons is depressed during the late slow EPSP by decrease of ACh release from preganglionic endings (Hasuo and Akasu, 1988). Ionic mechanisms of receptor activation in amphibian ganglia have been extensively reviewed by Smith (1994).…”

Section: Figsmentioning

confidence: 99%

Synaptic organization of amphibian sympathetic ganglia

Lascar

Eugène

Taxi

1996

Microsc. Res. Tech.

View full text Add to dashboard Cite

The synaptic organization of the amphibian sympathetic ganglia was studied, especially in the last two abdominal paravertebral ganglia of the frog. These ganglia appear to form a monosynaptic relay, not containing interneurons. They consist of two systems working in parallel: the principal neurons, by far the most numerous, and a small number of chromaffin (i.e., SIF) cells, usually arranged in clusters. Each principal neuron is innervated by a preganglionic branch forming a set of cholinergic synapses which exhibit classical ultrastructure. The only peculiarity is the presence of a subsynaptic apparatus in a variable percentage of synaptic complexes. Electrophysiological studies have demonstrated that synaptic transmission is due to ACh release and involves several postsynaptic potentials. Moreover, the principal neurons are of two types, B and C, whose preganglionic axons and their own axons have different conduction velocities. C neurons tend to be small in diameter, and B neurons are larger, but the size distribution of the two populations overlaps. More recently, it was demonstrated that these two neuronal systems have different immunocytochemical features. The C preganglionic fibers contain an LHRH-like peptide, which is responsible for late synaptic events. The B preganglionic fibers contain CGRP, whose role has not yet been established. The principal neurons all contain adrenaline, but neuropeptide Y is also present in C neurons and could be a second transmitter at peripheral junctions. SP-containing fibers also pass through the ganglia, but give rise to intraganglionic synapses only rarely, except in the celiac plexus. Galanin can coexist with neuropeptide Y in certain C neurons. Numerous principal neurons are immunoreactive for VIP. Chromaffin cells contain noradrenaline and metenkephalin, and some contain SP or LHRH; they are endocrine cells controlled by preganglionic fibers and can have a modulatory effect on principal neurons endowed with appropriate receptors. The accessibility of frog abdominal ganglia and the anatomical separation of B and C preganglionic fiber pathways provide interesting systems in which to carry out experimentation on the stability and specificity of synaptic contacts. After postganglionic axotomy, the majority of synapses disappear by disruption of synaptic contacts. There is a certain discrepancy between the recovery of synaptic transmission and the reappearance of morphologically identifiable synapses, suggesting that a certain amount of transmission is possible at contacts devoid of synaptic complexes. The selective deafferentation of B or C neurons showed that the subsynaptic apparati are mainly found at B neuron synapses. The course of reinnervation following selective deafferentation reveals the existence of different specificities at B and C synapses: C neurons are easily reinnervated by B preganglionic fibers, whereas C fibers appear fairly ineffective at reinnervating B neurons, even after a long interval. Attempts were made to reinnervate ganglionic neurons with som...

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The Dawn and Foundation of Slow Synaptic Potentials and Modulation

Koketsu

2000

Slow Synaptic Responses and Modulation

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Peptidergic inhibition of cholinergic transmission in bullfrog sympathetic ganglia.

Cited by 4 publications

References 38 publications

Synaptic organization of amphibian sympathetic ganglia

Synaptic organization of amphibian sympathetic ganglia

Synaptic organization of amphibian sympathetic ganglia

The Dawn and Foundation of Slow Synaptic Potentials and Modulation

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