Substance P inhibits the action potentials in bullfrog sympathetic ganglion cells.
Substance P (0.5-5 microM) depressed the spike peak and after-hyperpolarization of action potentials of bullfrog sympathetic ganglion cells. It also depressed the after-hyperpolarization and prolonged the falling phase in Ca2+ spikes. The voltage-dependent K+ currents, both the delayed rectifier K+ current (Ik1) and the M current (Ik2), were suppressed by substance P, suggesting that the depression of the after-hyperpolarization may be due to suppression of these K+ currents.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D004553:Electric Conductivity; D005728:Ganglia, Sympathetic / Q000166:cytology / Q000187:drug effects*; D008564:Membrane Potentials / Q000187:drug effects; D011892:Rana catesbeiana; D013373:Substance P / Q000494:pharmacology*; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology
D013757:Tetraethylammonium Compounds; D013373:Substance P; D013779:Tetrodotoxin; D019789:Tetraethylammonium