Pharmacological characterization of a 5-hydroxytryptamine-sensitive receptor/adenylate cyclase complex in the mandibular closer muscles of the cricket, Gryllus domestica.
The mandibular closer muscles of the cricket, Gryllus domestica, contain a 5-hydroxytryptamine (5-HT)-sensitive receptor that is coupled to adenylate cyclase. A structure-activity study of the 5-HT molecule indicates that the integrity of the ethylamine sidegroup and the presence of a negatively charged moiety at the 5 position (-OH, -OCH3) are essential for activity. A pharmacological profile is presented for this receptor. The receptor differs from any reported mammalian 5-HT receptor in that none of the mammalian agonists tested were effective. However, the mammalian antagonists for 5-HT receptors, spiperone, mianserin, and ketanserin as well as the anti-histaminic cyproheptadine were all effective antagonists in this preparation. Preliminary analysis of antagonism, particularly by spiperone, shows that these antagonists are probably acting non-competitively. On the basis of the pharmacological data, and comparisons with other insect systems, the 5-HT receptor present in the cricket mandibular muscles has been tentatively classified as 5-HT2-like.
Baines
R A
RA
Department of Biology, University of Waterloo, Ontario, Canada.
Downer
R G
RG
D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D001679:Biogenic Amines / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006135:Gryllidae / Q000378:metabolism*; D007700:Kinetics; D009132:Muscles / Q000187:drug effects / Q000378:metabolism*; D011985:Receptors, Serotonin / Q000378:metabolism*; D012701:Serotonin / Q000031:analogs & derivatives / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology
D001679:Biogenic Amines; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D012701:Serotonin; D000242:Cyclic AMP; D000262:Adenylyl Cyclases