title: Adenosine A1 receptors inhibit both adenylate cyclase activity and TRH-activated Ca2+ channels by a pertussis toxin-sensitive mechanism in GH3 cells.
abstract: The present study has examined the effects of adenosine A1 receptors on second messenger processes in GH3 cells. A1 receptors are present which are shown to inhibit adenylate cyclase in a GTP-requiring manner. Hormone (VIP) stimulation is also absolutely required for the observation of inhibition. Adenosine A1 receptor analogues also inhibit TRH-stimulated [Ca2+]i-mobilization in GH3 cells. Both effects of the adenosine receptor agonists are apparently mediated by pertussis toxin substrates, of which there are two--41,000 and 40,000 daltons respectively--in these cells. Somatostatin exerts analogous effects to the adenosine agonists in GH3 cells. Thus it may turn out that a general property of 'cyclase inhibitory receptors' is also to inhibit [Ca2+]i-mobilization in the same cells, when such mechanisms are present.
authors.affiliation: Department of Pharmacology, University of Colorado Health Sciences Center, Denver 80262.
authors.forename: D M
authors.initials: DM
authors.lastname: Cooper
authors.forename: K K
authors.initials: KK
authors.lastname: Caldwell
authors.forename: C L
authors.initials: CL
authors.lastname: Boyajian
authors.forename: D W
authors.initials: DW
authors.lastname: Petcoff
authors.forename: W
authors.initials: W
authors.lastname: Schlegel
mesh_terms: D037361:Adenylate Cyclase Toxin; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D015220:Calcium Channels / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D019204:GTP-Binding Proteins / Q000187:drug effects / Q000502:physiology*; D037342:Pertussis Toxin; D010660:Phenylisopropyladenosine / Q000494:pharmacology; D011983:Receptors, Purinergic / Q000502:physiology*; D013004:Somatostatin / Q000502:physiology; D013973:Thyrotropin-Releasing Hormone / Q000502:physiology*; D014660:Vasoactive Intestinal Peptide / Q000502:physiology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D037361:Adenylate Cyclase Toxin; D015220:Calcium Channels; D011983:Receptors, Purinergic; D010566:Virulence Factors, Bordetella; D010660:Phenylisopropyladenosine; D014660:Vasoactive Intestinal Peptide; D013004:Somatostatin; D013973:Thyrotropin-Releasing Hormone; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D000262:Adenylyl Cyclases