title: A specific G(o) heterotrimer couples somatostatin receptors to voltage-gated calcium channels in RINm5F cells.
abstract: The peptide hormone somatostatin inhibits glucose-induced insulin secretion in the rat insulinoma RINm5F cells by inhibition of voltage-gated calcium channels. Here we used micro-injection of antisense oligonucleotides directed against subtypes of G-protein subunits to determine the subunit composition involved in somatostatin-induced inhibition of voltage-gated calcium channels in RINmF5 cells. Injection of antisense oligonucleotides annealing to the respective mRNA of G alpha o2, G beta 1 and G gamma 3 reduced the somatostatin-induced inhibition of calcium channels in these cells. Injection of antisense oligonucleotides directed against other G-protein subunits did not, suggesting that in RINm5F cells the somatostatin receptor couples to a G protein of G alpha o2 beta 1 gamma 3 composition. By using a selective agonist of type 2 somatostatin receptors (SSTR 2) NC 8-12, we identified this receptor as the subtype coupling to calcium channels in RINm5F cells.
authors.affiliation: Institut für Pharmakologie, Freie Universität Berlin, Germany.
authors.forename: V E
authors.initials: VE
authors.lastname: Degtiar
authors.forename: B
authors.initials: B
authors.lastname: Wittig
authors.forename: G
authors.initials: G
authors.lastname: Schultz
authors.forename: F
authors.initials: F
authors.lastname: Kalkbrenner
mesh_terms: D000818:Animals; D015220:Calcium Channels / Q000502:physiology*; D019204:GTP-Binding Proteins / Q000737:chemistry / Q000502:physiology*; D019004:Galanin / Q000494:pharmacology; D007340:Insulinoma; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology*; D016376:Oligonucleotides, Antisense; D018408:Patch-Clamp Techniques; D051381:Rats; D017481:Receptors, Somatostatin / Q000502:physiology*; D013004:Somatostatin / Q000502:physiology; D014407:Tumor Cells, Cultured; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
chemical_list: D015220:Calcium Channels; D016376:Oligonucleotides, Antisense; D017481:Receptors, Somatostatin; D010566:Virulence Factors, Bordetella; D013004:Somatostatin; D019004:Galanin; C093733:somatostatin receptor 2; D019204:GTP-Binding Proteins