title: Metabotropic glutamate receptor subtype 1A activates adenylate cyclase when expressed in baby hamster kidney cells.
abstract: 1. The coupling of subtype mGluR1a of the metabotropic glutamate receptor family to phosphoinositide hydrolysis, cAMP-formation and arachidonic acid release was characterized when the receptor was expressed in baby hamster kidney (BHK) cells. 2. When measuring cAMP-formation in BHK cells expressing mGluR1a, the rank order of agonist potency as well as the efficacy of mGluR1a antagonists was comparable to what has been observed when measuring mGluR1a-mediated phosphoinositide (PI)-hydrolysis. 3. However, while the presence of extracellular calcium increased the efficacy of quisqualate to stimulate phosphoinositide hydrolysis no significant effects were observed when measuring quisqualate-induced cAMP-formation. 4. Pretreatment of mGluR1a-expressing cells with pertussis toxin increased quisqualate-induced cAMP-formation in contrast to the observed partial inhibition of PI-hydrolysis by pertussis toxin. Cholera toxin increased cAMP-formation in BHK cells but showed no effects on PI-hydrolysis. 5. While quisqualate also stimulated [3H]-arachidonic acid release from BHK cells expressing mGluR1a this effect may be secondary to activation of phospholipase C. 6. These data further suggest that mGluR1a is coupled to PI-hydrolysis as well as cAMP-formation via different G-proteins which can be discriminated by their sensitivity to pertussis toxin.
authors.affiliation: Novo Nordisk A/S, Måløv, Denmark.
authors.forename: C
authors.initials: C
authors.lastname: Thomsen
mesh_terms: D037361:Adenylate Cyclase Toxin; D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D002772:Cholera Toxin / Q000494:pharmacology; D006224:Cricetinae; D000242:Cyclic AMP / Q000096:biosynthesis; D004789:Enzyme Activation / Q000502:physiology; D006868:Hydrolysis; D007668:Kidney / Q000201:enzymology*; D037342:Pertussis Toxin; D018094:Receptors, Metabotropic Glutamate / Q000096:biosynthesis / Q000187:drug effects / Q000378:metabolism*; D015290:Second Messenger Systems / Q000502:physiology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D037361:Adenylate Cyclase Toxin; D018094:Receptors, Metabotropic Glutamate; D010566:Virulence Factors, Bordetella; D016718:Arachidonic Acid; D002772:Cholera Toxin; D000242:Cyclic AMP; D037342:Pertussis Toxin; D000262:Adenylyl Cyclases