Premium
Morphine attenuates cholinergic nerve activity in human isolated colonic muscle
Author(s) -
Burleigh David E.,
Trout Stephen J.
Publication year - 1986
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.1476-5381.1986.tb10206.x
Subject(s) - acetylcholine , endocrinology , medicine , cholinergic , chemistry , taenia coli , stimulation , morphine , tetrodotoxin , choline , (+) naloxone , biology , calcium , antagonist , receptor
1 The action of morphine on cholinergic nerves in human sigmoid taenia coli muscle strips (taenia) was investigated using a radiolabelling technique. 2 Basal release of tritiated material from taenia was increased by electrical field stimulation (EFS). This increase was tetrodotoxin (3.14 μM)‐sensitive and calcium‐dependent. Analysis of basal and stimulated release of tritiated material indicated that evoked release (i.e. stimulated minus basal) is almost entirely due to an increase in [ 3 H]‐acetylcholine ([ 3 H]‐ACh) output. 3 Evoked release of [ 3 H]‐ACh was dependent on the current strength and could be greatly reduced by exposing taenia to hemicholinium (34.8, 87.0 μM) before and during incubation with [ 3 H]‐choline (4 μCi ml −1 , 15 Ci mmol −1 ). 4 Spontaneous activity, muscle tone and the motor response of taenia to EFS were unaffected by morphine. 5 Evoked, but not basal, release of tritiated material was inhibited by morphine (1.32‐13.20 μM) in a concentration‐dependent manner. The inhibition of release was frequency‐dependent and naloxone (0.28 μM)‐sensitive. 6 The possible relationship between the effects of morphine on cholinergic nerves in taenia muscle and its actions in vivo are discussed.