Effects of somatostatin on potassium currents in bullfrog sympathetic ganglion neurones: possible role of receptor subtypes.
The effects of whole somatostatin (wSS; somatostatin-28) and cyclic somatostatin (cSS; somatostatin-14) were examined on patch-clamped bullfrog sympathetic ganglion neurones. In the C-cells, where muscarine produces hyperpolarization, wSS was also inhibitory and activated an inwardly-rectifying K+ current; cSS was ineffective. By contrast, in the B-cells, where muscarine produces excitatory effects, cSS was also excitatory and was more effective than wSS in suppressing a voltage-dependent, non-inactivating K(+)-current (IM). These results are consistant with the idea that excitatory and inhibitory effects of somatostatin-derived peptides may be mediated via different receptor subtypes.
Department of Pharmacology, University of Alberta, Edmonton, Canada.
D E
DE
Kurenny
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H
Chen
P A
PA
Smith
D000818:Animals; D005728:Ganglia, Sympathetic / Q000166:cytology / Q000187:drug effects*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000187:drug effects*; D015221:Potassium Channels / Q000187:drug effects*; D011892:Rana catesbeiana; D017981:Receptors, Neurotransmitter / Q000187:drug effects*; D017481:Receptors, Somatostatin; D013004:Somatostatin / Q000494:pharmacology*
D015221:Potassium Channels; D017981:Receptors, Neurotransmitter; D017481:Receptors, Somatostatin; D013004:Somatostatin