Bai_1992_Arch.Insect.Biochem.Physiol_21_289

The actions of acetylcholine and cholinergic ligands have been studied using dorsal midline neurones from the rnetathoracic ganglion of the cockroach Periplaneta americana.Both nicotine and oxotremorine depolarized dorsal midline neuronal cell bodies.Dose-response curves for nicotine and oxotremorine saturated at different levels. Nicotine-induced depolarizations were completely or partially blocked by mecamylamine, d-tubocurarine, strychnine, and bicuculline, but were insensitive to alpha-bungarotoxin(100 nM), atropine (100 micronM),Scopolamine (10 micronM), and pirenzepine (50 micronM). Following pretreatment with collagenase, the dorsal midline neurones were sensitive to high doses of alpha-bungarotoxin (3 micronM). Oxotremorine-induced depolarizations were blocked by scopolamine (10 micronM) atropine (100 micronM), and pirenzepine (50 micronM) and were insensitive to mecamylamine (10 micronM) and d-tubocurarine (100 micronM). The results indicate the coexistence of at least two distinct acetylcholine receptors on dorsal midline neuronal cell bodies in the cockroach metathoracic ganglion.