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RANITIDINE INHIBITS ADRENERGIC TRANSMISSION IN THE RAT ISOLATED ANOCOCCYGEUS MUSCLE
Author(s) -
Gwee M. C. E.,
Cheah L. S.
Publication year - 1992
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1992.tb00483.x
Subject(s) - ranitidine , adrenergic , medicine , chemistry , endocrinology , stimulation , endogeny , smooth muscle , pharmacology , receptor , biology
SUMMARY 1. The effects of ranitidine on adrenergic transmission in the rat isolated anococcygeus muscle were investigated. 2. Cumulative doses (2–8 mmol/ L) of ranitidine produced a concentration‐dependent inhibition of motor responses of the rat isolated anococcygeus muscle evoked by field stimulation (20–25 V, 10 Hz for 10 s, 1 ms pulse width) every 2 min, but also potentiated the contractile response to exogenous noradrenaline (5 μmol/L). The inhibited motor responses recovered rapidly and completely after washing out ranitidine. 3. 4‐Aminopyridine (100 μmol/L) effectively reversed the partially inhibited (55% or greater) motor responses. 4. The results strongly suggest that ranitidine can inhibit adrenergic transmission in the anococcygeus muscle by a prejunctional mechanism with, presumably, consequent development of supersensitivity of the effector cells to noradrenaline.