title: A calcium-dependent acetylcholine depolarization blocked by methoxyverapamil (D600) and procaine in snail neurones.
abstract: 1 Repetitive application of acetylcholine (ACh) revealed two types of ACh depolarization in two types of snail neurone, depending on their desensitization properties. 2 Further experiments were carried out on neurones which displayed a rapidly desensitizing response. 3 The amplitude of the response depended on the external sodium and calcium levels. 4 Procaine antagonized ACh effects with the same efficiency as atropine or hexamethonium, half maximal depression being obtained at a concentration of 10(-4) M. The blocking effect was independent of the dose of ACh. 5 The depression of the ACh-induced depolarization by cobalt ions and D600 suggests that calcium may participate in this response.
mesh_terms: D000109:Acetylcholine / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology / Q000502:physiology*; D003035:Cobalt / Q000494:pharmacology; D005711:Gallopamil / Q000494:pharmacology*; D006372:Helix, Snails; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000187:drug effects*; D011343:Procaine / Q000494:pharmacology*; D014700:Verapamil / Q000031:analogs & derivatives*
chemical_list: D005711:Gallopamil; D003035:Cobalt; D011343:Procaine; D014700:Verapamil; D000109:Acetylcholine; D002118:Calcium