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AN ELECTROPHYSIOLOGICAL STUDY OF THE ACTION OF CRUDE Enhydrina schistosa VENOM
Author(s) -
FERRY C.B.,
GEH SOO LIN
Publication year - 1977
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.1476-5381.1977.tb07745.x
Subject(s) - venom , electrophysiology , depolarization , carbachol , acetylcholine , acetylcholine receptor , phrenic nerve , neuromuscular junction , extracellular , chemistry , biophysics , receptor , pharmacology , medicine , biology , anatomy , biochemistry , neuroscience , respiratory system
1 Electrophysiological studies on the rat diaphragm revealed that crude Enhydrina schistosa venom has a blocking action on postjunctional acetylcholine (ACh) receptors. 2 This venom in concentrations of 0.125‐1.0 μg/ml abolished the extracellular endplate potential (e.e.p.p.) without altering the presynaptic spike. When the phrenic nerve was stimulated at a frequency of 1 Hz the degree of depression of successive e.e.p.ps was approximately the same in records made before and after treatment with venom. 3 In concentrations of 0.25 and 0.5 μg/ml the venom reduced significantly the amplitude of miniature endplate potentials (m.e.p.ps). The frequency of m.e.p.ps did not increase but was decreased when the amplitude of the m.e.p.ps was much reduced. 4 The crude venom did not alter the resting membrane potential (RMP) of the muscle cell. 5 The venom inhibited the depolarization of the muscle membrane caused by carbachol. 6 It is concluded that an active component in the crude venom is responsible for a blocking action on postjunctional receptors.