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Substance P inhibits the M‐current in bullfrog sympathetic neurones
Author(s) -
Adams P.R.,
Brown D.A.,
Jones S.W.
Publication year - 1983
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1983.tb11004.x
Subject(s) - bullfrog , depolarization , voltage clamp , biophysics , membrane potential , chemistry , current (fluid) , electrophysiology , sympathetic ganglion , rana , endocrinology , medicine , biology , physics , thermodynamics
Substance P (SP, 2.5–10 μ m ) was applied by rapid bath perfusion to bullfrog lumbar sympathetic neurones in vitro , voltage‐clamped through a single micro‐electrode. In unclamped cells, SP produced a depolarization accompanied by an increase in apparent input resistance. Under voltage‐clamp a voltage‐dependent inward current was induced by SP, during which the time‐dependent relaxations induced by square voltage commands were inhibited. It is concluded that SP inhibits the M‐current (I M ), a species of voltage‐dependent K + ‐current, and that I M ‐inhibition was the primary cause of the inward current and membrane depolarization in the cells tested.