An after-depolarization following action potentials and its modulation by substance P in rat sympathetic neurons.
Sympathetic neurons in rat coeliac-superior mesenteric ganglia (C-SMG) displayed an after-depolarization (ADP) following action potentials and after-hyperpolarization. The ADP had amplitudes of 3-10 mV and lasted for 2-6 s, during which membrane resistance and excitability of C-SMG neurons increased. The reversal potential of ADP was dependent on external K+ concentrations. The ADP was suppressed in a solution containing Cd2+ or zero Ca2+. The ADP thus appears to be produced by inhibition of certain K+ channels via a Ca(2+)-dependent process. Substances P (SP) depolarized ganglion cells and increased the ADP, leading to a long-lasting increase in membrane excitability of rat C-SMG neurons.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D005728:Ganglia, Sympathetic / Q000166:cytology / Q000187:drug effects; D066298:In Vitro Techniques; D009469:Neuromuscular Junction / Q000187:drug effects* / Q000502:physiology; D009474:Neurons / Q000187:drug effects*; D015221:Potassium Channels / Q000187:drug effects; D051381:Rats; D013373:Substance P / Q000494:pharmacology*; D013564:Sympathetic Nervous System / Q000166:cytology / Q000187:drug effects / Q000502:physiology*
D015221:Potassium Channels; D013373:Substance P