Somatostatin modulates voltage-dependent Ca2+ channels in GH3 cells via a specific G(o) splice variant.
In rat pituitary GH3 cells Ca2+ current through L-type channels is reduced by somatostatin. This modulation of channel activity by somatostatin receptors is mediated by a guanine nucleotide-binding regulatory protein (G protein). It is sensitive to pertussis toxin, indicating the involvement of a G(o)- or Gi-type G protein in this pathway. The identity of this G protein was determined by suppressing the expression of endogenous G proteins individually via intranuclear injection of antisense oligonucleotides. This method was applied to GH3 cells to screen several G protein alpha, beta and gamma subunits for their roles in the defined signal transduction pathway. The loss of somatostatin's modulating activity on the voltage-dependent Ca2+ channel after oligonucleotide injection revealed the involvement of G(o) alpha 2 beta 1 gamma 3 to the exclusion of other closely related subtypes.
Kleuss
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Institut für Molekularbiologie und Biochemie, Freie Universität Berlin, Germany.
D000818:Animals; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D019204:GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D010902:Pituitary Gland / Q000378:metabolism*; D051381:Rats; D015398:Signal Transduction; D013004:Somatostatin / Q000378:metabolism* / Q000494:pharmacology
D015220:Calcium Channels; D013004:Somatostatin; D019204:GTP-Binding Proteins