title: Beta-3 adrenergic stimulation of L-type Ca(2+) channels in rat portal vein myocytes.
abstract: 1. The effects of beta(3)-adrenergic stimulation were studied on the L-type Ca(2+) channel in single myocytes from rat portal vein using the whole-cell mode of the patch-clamp technique. 2. Reverse transcription-polymerase chain reaction showed that beta(1)-, beta(2)- and beta(3)-adrenoceptor subtypes were expressed in rat portal vein myocytes. Application of both propranolol (a non-selective beta(1)- and beta(2)-adrenoceptor antagonist) and SR59230A (a beta(3)-adrenoceptor antagonist) were needed to inhibit the isoprenaline-induced increase in L-type Ca(2+) channel current. 3. L-type Ca(2+) channels were stimulated by CGP12177A (a beta(3)-adrenoceptor agonist with potent beta(1)- and beta(2)-adrenoceptor antagonist property) in a manner similar to that of isoprenaline. The CGP12177A-induced stimulation of Ca(2+) channel current was blocked by SR59230A, cyclic AMP-dependent protein kinase inhibitors, H-89 and Rp 8-Br-cyclic AMPs, but was unaffected by protein kinase C inhibitors, GF109203X and 19-31 peptide. This stimulation was mimicked by forskolin and 8-Br-cyclic AMP. In the presence of okadaic acid (a phosphatase inhibitor), the beta(3)-adrenoceptor-induced stimulation was maintained after withdrawal of the agonist. 4. The beta(3)-adrenoceptor stimulation of L-type Ca(2+) channels was blocked by a pretreatment with cholera toxin and by the intracellular application of an anti-Galpha(s) antibody. This stimulation was unaffected by intracellular infusion of an anti-Gbeta(com) antibody and a betaARK(1) peptide. 5. These results show that activation of beta(3)-adrenoceptors stimulates L-type Ca(2+) channels in vascular myocytes through a Galpha(s)-induced stimulation of the cyclic AMP/protein kinase A pathway and the subsequent phosphorylation of the channels.
authors.affiliation: Laboratoire de Physiologie Cellulaire et Pharmacologie Moléculaire, CNRS UMR 5017, Université de Bordeaux II, 146 rue Léo Saignat, 33076 Bordeaux Cedex, France.
authors.forename: P
authors.initials: P
authors.lastname: Viard
authors.forename: N
authors.initials: N
authors.lastname: Macrez
authors.forename: F
authors.initials: F
authors.lastname: Coussin
authors.forename: J L
authors.initials: JL
authors.lastname: Morel
authors.forename: J
authors.initials: J
authors.lastname: Mironneau
mesh_terms: D000433:1-Propanol / Q000494:pharmacology; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D001464:Barium / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D002772:Cholera Toxin / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D007545:Isoproterenol / Q000494:pharmacology; D007546:Isoquinolines / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D011169:Portal Vein / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D011412:Propanolamines / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D022702:Receptors, Adrenergic, beta-3; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013449:Sulfonamides
chemical_list: C097869:3-(2-ethylphenoxy)-1-(1,2,3,4-tetrahydronaphth-1-ylamino)-2-propanol oxalate; D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D020746:Calcium Channels, L-Type; D007546:Isoquinolines; D011412:Propanolamines; D012333:RNA, Messenger; D011943:Receptors, Adrenergic, beta; D022702:Receptors, Adrenergic, beta-3; D013449:Sulfonamides; D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D001464:Barium; D015240:Phorbol 12,13-Dibutyrate; D002772:Cholera Toxin; D000433:1-Propanol; D007545:Isoproterenol; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide; C033394:CGP 12177