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Synaptic inhibition of the M‐current: slow excitatory post‐synaptic potential mechanism in bullfrog sympathetic neurones.
Author(s) -
Adams P R,
Brown D A
Publication year - 1982
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1982.sp014412
Subject(s) - bullfrog , excitatory postsynaptic potential , membrane potential , hyperpolarization (physics) , biophysics , chemistry , reversal potential , resting potential , depolarization , conductance , synaptic potential , neuroscience , electrophysiology , inhibitory postsynaptic potential , endocrinology , biology , patch clamp , physics , stereochemistry , condensed matter physics , nuclear magnetic resonance spectroscopy
1. Slow muscarinic excitatory post‐synaptic currents (slow e.p.s.c.s) generated by preganglionic nerve stimuli were recorded in voltage‐clamped bullfrog sympathetic neurones. 2. IM‐‐an outward, voltage‐dependent, K+‐current‐‐was inhibited during the slow e.p.s.c., and membrane conductance was reduced in a voltage‐dependent manner. 3. The slow e.p.s.c. was associated with reduced outward rectification in the steady‐state current‐‐voltage (I/V) curve at membrane potentials more positive than‐‐60 m V, with no change in the shape of the non‐rectifying part of the I/V curve at more negative potential. 4. The amplitude of the slow e.p.s.c. was reduced by membrane hyperpolarization, to zero at membrane potentials equal to, or more negative than, ‐60 m V. The voltage sensitivity of the slow e.p.s.c. accorded with that of IM. 5. It is concluded that the slow e.p.s.c. results from a selective inhibition of IM.