Selective inhibition of mesolimbic behavioral supersensitivity by naloxone.
Rats trained on ventral tegmental intracranial self-stimulation (ICSS) were unaffected by acute injection of naloxone (2 mg/kg), while acute morphine (5 mg/kg) increased ICSS rate by 46%. Chronic haloperidol (1 mg/kg/day for 21 days) produced mesolimbic dopaminergic supersensitivity, as seen by 42% increase in ICSS. Acute naloxone partially blocked this supersensitivity (to 13% over basal), while acute morphine augmented it (66% over basal). These findings suggest that enkephalinergic systems may be involved in neuroleptic-induced dopaminergic behavioral supersensitivity.
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D004298:Dopamine / Q000502:physiology; D006220:Haloperidol / Q000494:pharmacology; D008032:Limbic System / Q000187:drug effects*; D008297:Male; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000494:pharmacology*; D051381:Rats; D012653:Self Stimulation
D009270:Naloxone; D009020:Morphine; D006220:Haloperidol; D004298:Dopamine