Changes in the sensitivity of smooth muscle to neurotransmitter during acute morphine treatment and its association with analgesia.
Acute in vivo administration of morphine to mice produced dose- and time-dependent subsensitivity to acetylcholine in ileum and supersensitivity to norepinephrine in vas deferens. These responses were specific to the agonist as potassium chloride-induced responses were not altered. A correlation was observed between the analgesia and the sensitivity changes produced by morphine. The sensitivity changes were mediated through opiate receptors as naloxone antagonised the effect of morphine.
D000109:Acetylcholine / Q000494:pharmacology; D000698:Analgesia; D000818:Animals; D004305:Dose-Response Relationship, Drug; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D009020:Morphine / Q000494:pharmacology*; D009130:Muscle, Smooth / Q000187:drug effects*; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D009638:Norepinephrine / Q000494:pharmacology; D011957:Receptors, Opioid / Q000187:drug effects; D013997:Time Factors; D014649:Vas Deferens / Q000187:drug effects
D018377:Neurotransmitter Agents; D011957:Receptors, Opioid; D009020:Morphine; D000109:Acetylcholine; D009638:Norepinephrine