Histamine H2 receptors mediate morphine-induced locomotor hyperactivity of the C57BL/6J mouse.
Morphine-induced locomotor hyperactivity of the C57BL/6J mouse was challenged with intracranial injections of antihistamines or the opiate antagonist naloxone. When cimetidine (H2 receptor blocker) was injected into the nucleus accumbens/stria terminalis, it significantly reduced opiate-stimulated locomotion. However, ventricular injections of cimetidine did not significantly alter either morphine or amphetamine hyperactivity, nor did cimetidine depress spontaneous locomotion. Although naloxone eliminated morphine-induced locomotion when injected into either the nucleus accumbens or the ventricles, chlorpheniramine (H1 receptor blocker) failed to reduce this behavior. These data suggest that opiate-stimulated locomotion of the C57BL/6J mouse may be partially mediated by histamine H2 receptors of the nucleus accumbens or closely adjacent structures.
D000679:Amygdala / Q000502:physiology; D000818:Animals; D008032:Limbic System / Q000187:drug effects / Q000502:physiology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009020:Morphine / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects*; D009434:Neural Pathways / Q000502:physiology; D009714:Nucleus Accumbens / Q000187:drug effects / Q000502:physiology; D011968:Receptors, Histamine / Q000502:physiology*; D011970:Receptors, Histamine H2 / Q000502:physiology*
D011968:Receptors, Histamine; D011970:Receptors, Histamine H2; D009020:Morphine