title: Effects of McN-A-343 on insect neurosecretory cells: evidence for muscarinic-like receptor subtypes.
abstract: The muscarinic agonist McN-A-343 has been used to characterize the muscarinic receptors on somata of adult cockroach dorsal unpaired median (DUM) neurones maintained in short-term culture. Pressure application of McN-A-343 onto isolated DUM neurones induced a dose- and voltage-dependent biphasic response composed of a fast initial hyperpolarization followed by a slow depolarizing phase, recorded with the patch-clamp technique in the whole-cell recording configuration. The fast hyperpolarization reversed at an extrapolated potential value of -91.04 mV and was fully antagonized by the M2 muscarinic antagonist methoctramine. The slow depolarizing component reversed at an extrapolated value of -28.33 mV and was inhibited by the M1 muscarinic antagonist pirenzepine. These results demonstrate both a specific effect for McN-A-343 on DUM neurones and the existence of two functionally distinct muscarinic-like receptor subtypes governing this McN-A-343-induced biphasic response.
authors.affiliation: Laboratoire de Neurophysiologie, CNRS URA 611, Université d'Angers, France.
authors.forename: B
authors.initials: B
authors.lastname: Lapied
authors.forename: F
authors.initials: F
authors.lastname: Tribut
authors.forename: B
authors.initials: B
authors.lastname: Hue
mesh_terms: D008455:(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethylammonium Chloride / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D003058:Cockroaches / Q000502:physiology*; D003959:Diamines / Q000494:pharmacology; D005724:Ganglia / Q000166:cytology / Q000378:metabolism; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009490:Neurosecretory Systems / Q000166:cytology / Q000187:drug effects*; D010890:Pirenzepine / Q000494:pharmacology; D011976:Receptors, Muscarinic / Q000187:drug effects*
chemical_list: D003959:Diamines; D011976:Receptors, Muscarinic; D010890:Pirenzepine; D008455:(4-(m-Chlorophenylcarbamoyloxy)-2-butynyl)trimethylammonium Chloride; C054938:methoctramine