[Opposite actions of ACh on excitatory and inhibitory synaptic transmission in cultured rat cortical neurons].
Effect of ACh on spontaneous EPSC and IPSC in cultured postnatal rat cortical neurons was studied using whole-cell voltage-clamp technique. EPSC was blocked by a non-NMDA glutamate receptor antagonist DNQX, while IPSC was blocked by a GABAA receptor antagonist bicuculline. When ACh (10-100 mumol/L) was applied by puff pipettes to the cells recorded, the frequency of EPSC was enhanced greatly, but the amplitude distribution was not changed significantly. However, the frequency of IPSC was attenuated by ACh even at a quite low concentration (1 mumol/L). The effect of ACh on EPSC and IPSC could be blocked by M type ACh receptor antagonist atropine (1 mumol/L). ACh had no significant effect on whole-cell currents activated by glutamate and GABA. The above results provide evidence that ACh has opposite effects on excitatory and inhibitory synaptic transmission in rat cortex by acting at presynaptic sites. It is also suggested that ACh plays an important role in the maintenance of excitability of cortical neurons.
Liu
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Institute of Toxicology and Pharmacology, Academy of Military Medical Sciences, Beijing.
He
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Liu
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D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D009474:Neurons / Q000502:physiology; D018408:Patch-Clamp Techniques; D017729:Presynaptic Terminals; D051381:Rats; D017208:Rats, Wistar; D017470:Receptors, Glutamate; D009435:Synaptic Transmission
D017470:Receptors, Glutamate; D000109:Acetylcholine