Premium
Effects of H 1 receptor blocking drugs on the frog sartorius neuromuscular junction
Author(s) -
Katayama Sohta,
Tasaka Kenji
Publication year - 1985
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.1476-5381.1985.tb11072.x
Subject(s) - sartorius muscle , chemistry , membrane potential , biophysics , receptor , acetylcholine receptor , postsynaptic potential , atropine , electrophysiology , perfusion , time constant , neuromuscular junction , endocrinology , medicine , biology , neuroscience , biochemistry , engineering , electrical engineering
1 The effects of H 1 ‐receptor blocking agents, pyrilamine, promethazine, and diphenhydramine, on the amplitude and time course of endplate potentials (e.p.ps) were studied in the sartorius muscles of frogs. 2 H 1 ‐receptor blockers (10 −5 ‐10 −4 M) reduced the amplitude of e.p.ps recorded intracellularly without affecting the resting membrane potential. 3 The acetylcholine potential was decreased by perfusion of H 1 ‐preceptor blockers. However, when the muscle fibre was stimulated directly, threshold and magnitude of action potential were not affected by H 1 ‐receptor blockers. 4 The time constant of decay of the e.p.ps recorded extracellularly was reduced by H 1 ‐receptor blockers and the decay remained exponential with a single time constant. 5 The quantal content was not reduced by perfusion of H 1 ‐receptor blockers at a concentration of 10 −4 M. 6 It is assumed that the major site of action of these H 1 ‐receptor blocking agents is at the postsynaptic membrane.