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THE EFFECTS OF MORPHINE ON THE RELEASE OF NORADRENALINE FROM THE MOUSE VAS DEFERENS
Author(s) -
HENDERSON G.,
HUGHES J.
Publication year - 1976
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.1476-5381.1976.tb10384.x
Subject(s) - vas deferens , endocrinology , phenoxybenzamine , morphine , medicine , stimulation , phentolamine , (+) naloxone , chemistry , opioid , receptor , propranolol
1 Electrical field stimulation of the mouse vas deferens (TO and C57/BL strains) caused the release of noradrenaline into the bathing medium. 2 Phenoxybenzamine (30 μ m ) or phentolamine (36 μ m ) plus cocaine (13 μ m ) caused a considerable increase in the noradrenaline output. 3 In the vasa deferentia from TO mice the output per pulse of noradrenaline was constant at frequencies of stimulation from 0.5 to 15 Hz whereas in the vasa deferentia from C57/BL mice the output per pulse of noradrenaline increased two‐fold from 1.5 to 15 Hz. 4 Morphine (2 μ m ) inhibited the contractions of the vasa deferentia from TO mice. This effect was greater at low (0.1‐1 Hz) than at high (10 Hz) frequencies of stimulation. Morphine (2 μ m ) did not inhibit the response of the tissue to exogenous noradrenaline. 5 Morphine (1 μ m ) reduced the noradrenaline output from the vasa deferentia of TO mice stimulated at 1.5 Hz but did not reduce the noradrenaline output at 15 Hz. At 1.5 Hz the reduction of noradrenaline output was reversed by naloxone (0.05 μ m ). 6 Morphine (5 μ m ) did not inhibit the uptake of [ 3 H]‐noradrenaline into the vasa deferentia from TO mice. 7 Only in high concentrations (ID 50 30.88 μ m ) did morphine inhibit the contractions of the vasa deferentia from C57/BL mice. 8 Normorphine (100 μ m ) did not reduce the noradrenaline output from vasa deferentia of C57/BL mice.