Substance P and somatostatin inhibit calcium channels in rat sympathetic neurons via different G protein pathwavs

Mark S. Shapiro, Bertil Hille

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We studied inhibition of N-type Ca2+ channels in rat superior cervical ganglion neurons by substance P (SP) and somatostatin-14 (Som). In whole-cell clamp, 70 of 82 acutely dissociated neurons showed inhibition (mean 37%) by 500 nM SP, and 54 of 61 showed inhibition by 240 nM Som (mean 57% ). Pertussis toxin (PTX) blocked Som but not SP inhibition; intracellular dialysis with 2 mM GDP-β-S attenuated inhibition with either peptide. Inhibition was voltage dependent with Som but not with SP. Neurokinin A (1 μM) or B was without effect, implicating NK1 tachykinin receptors. In cell-attached patches with bath-applied drugs, to test for a diffusible messenger, inhibition by SP or Som was only 8%. Thus, SP signaling is voltage independent and PTX insensitive; Som inhibition is voltage dependent and PTX sensitive; and both are membrane delimited.

Original languageEnglish (US)
Pages (from-to)11-20
Number of pages10
Issue number1
Publication statusPublished - Jan 1993


ASJC Scopus subject areas

  • Neuroscience(all)

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