The pharmacology of an insect ganglion: actions of carbamylcholine and acetylcholine.
1. Methods for presenting dose-response data for the ganglionic actions of cholinergic agonists (e.g. carbamylcholine) are compared, using the mannitol-gap technique for electrophysiological recording of synaptic events at the cercal nerve, giant fibre synapse of the sixth abdominal ganglion of the cockroach Periplaneta americana. 2. At concentrations around 10(-5)M, carbamylcholine has no effect on ganglionic polarization but potentiates the monosynaptic EPSP. At 10(-4)M and higher concentrations, ganglionic depolarization is accompanied by a reduction of EPSP. 3. Pretreatment with eserine (10(-6) M) considerably shifts the dose-response curve for acetylcholine so that synaptic transmission is consistently sensitive to 10(-6) M acetylcholine.
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D002217:Carbachol / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D005724:Ganglia / Q000187:drug effects* / Q000502:physiology; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D010526:Periplaneta; D010830:Physostigmine / Q000494:pharmacology; D011950:Receptors, Cholinergic; D009435:Synaptic Transmission
D011950:Receptors, Cholinergic; D002217:Carbachol; D010830:Physostigmine; D000109:Acetylcholine