title: Muscarinic M-current inhibition via G alpha q/11 and alpha-adrenoceptor inhibition of Ca2+ current via G alpha o in rat sympathetic neurones.
abstract: 1. Microinjection of selective antibodies into superior cervical ganglion (SCG) neurones has identified the G-protein alpha-subunits mediating muscarinic receptor inhibition of M-type K+ current (IK(M)) and alpha-adrenoceptor inhibition of Ca2+ current (ICa). 2. Antibodies specific for G alpha q/11, but not those for G alpha o, reduced M-current inhibition by the muscarinic agonist oxotremorine-M, whereas anti-G alpha o antibodies, but not anti-G alpha q/11 or anti-G alpha i1-3 antibodies, reduced calcium current inhibition by noradrenaline. 3. Immunoblots with specific anti-G-protein antibodies demonstrated the presence of both G alpha q and G alpha 11, while G alpha o1 (but virtually no G alpha o2) was present. 4. We conclude that M1 muscarinic receptor inhibition of IK(M) is transduced by G alpha q and/or G alpha 11, and that G alpha o transduces alpha-adrenoceptor inhibition of ICa.
authors.affiliation: Wellcome Laboratory for Molecular Pharmacology, Department of Pharmacology, University College London.
authors.forename: M P
authors.initials: MP
authors.lastname: Caulfield
authors.forename: S
authors.initials: S
authors.lastname: Jones
authors.forename: Y
authors.initials: Y
authors.lastname: Vallis
authors.forename: N J
authors.initials: NJ
authors.lastname: Buckley
authors.forename: G D
authors.initials: GD
authors.lastname: Kim
authors.forename: G
authors.initials: G
authors.lastname: Milligan
authors.forename: D A
authors.initials: DA
authors.lastname: Brown
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000818:Animals; D000906:Antibodies / Q000276:immunology; D002118:Calcium / Q000502:physiology*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D004553:Electric Conductivity; D019204:GTP-Binding Proteins / Q000276:immunology / Q000502:physiology*; D005728:Ganglia, Sympathetic / Q000166:cytology / Q000502:physiology*; D009474:Neurons / Q000502:physiology; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000145:classification / Q000502:physiology; D051381:Rats; D011976:Receptors, Muscarinic / Q000502:physiology*
chemical_list: D000316:Adrenergic alpha-Agonists; D000906:Antibodies; D002121:Calcium Channel Blockers; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D011976:Receptors, Muscarinic; D019204:GTP-Binding Proteins; D002118:Calcium