title: The muscle chemoreceptors of the ascidian Halocynthia aurantium.
abstract: The body wall muscle of the ascidian, Halocynthia aurantium, is sensitive to both nicotinomimetics and muscarinomimetics. Atropine (4 X 10(-11 M) and benzilylcholine mustard (1 X 10(-5) M for 15 min) selectively block responses to muscarinomimetics. d-Tubocurarine (2 X 10(-6) M) and hexadecamethylene-bis-trimethylammonium (2 X 10(-7) M) prevent contractions induced by both nicotinomimetics and muscarinomimetics. In the cold season of the year the sensitivity of the muscle to muscarinomimetics disappears while responses to nicotinomimetics do not change throughout the year. The cooling of the water in the experimental bath results in an increase in the muscle contractions caused by muscarinomimetics while the responses to nicotinomimetic propionylcholine do not change. Catecholamines induce a decrease of the ascidian muscle responses to acetylcholine, cGMP and papaverine produce a similar effect.
authors.forename: G T
authors.initials: GT
authors.lastname: Kobzar
authors.forename: S A
authors.initials: SA
authors.lastname: Shelkovnikov
mesh_terms: D000596:Amino Acids / Q000494:pharmacology; D000818:Animals; D002395:Catecholamines / Q000494:pharmacology; D006152:Cyclic GMP / Q000494:pharmacology; D009132:Muscles / Q000294:innervation; D010208:Papaverine / Q000494:pharmacology; D010276:Parasympatholytics / Q000494:pharmacology; D010277:Parasympathomimetics / Q000494:pharmacology; D011950:Receptors, Cholinergic / Q000187:drug effects / Q000502:physiology*; D012621:Seasons; D013696:Temperature; D014561:Urochordata / Q000502:physiology*
chemical_list: D000596:Amino Acids; D002395:Catecholamines; D010276:Parasympatholytics; D010277:Parasympathomimetics; D011950:Receptors, Cholinergic; D010208:Papaverine; D006152:Cyclic GMP