title: Voluntary morphine ingestion, morphine dependence, and recovery from withdrawal signs.
abstract: We are reporting on conditions (without forced drinking or premedications) where rats voluntarily drink high quantities of sucrose-morphine solutions in preference to water. The volume ingested is inversely related to the morphine concentration in the liquid. The morphine antagonist, nalorphine, produced a clear set of opiate withdrawal signs in these (voluntarily) morphine-drinking rats. The severity of withdrawal signs was a function of the amount of ingested morphine. The present finding is the first report to show that rats ingest high quantities of sucrose-morphine without premedication or forced hydration procedures.
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002755:Choice Behavior / Q000187:drug effects; D004327:Drinking Behavior / Q000187:drug effects; D006801:Humans; D008297:Male; D009020:Morphine / Q000008:administration & dosage*; D009021:Morphine Dependence / Q000209:etiology*; D009269:Nalorphine / Q000494:pharmacology; D051381:Rats; D013375:Substance Withdrawal Syndrome / Q000209:etiology*; D013395:Sucrose / Q000494:pharmacology; D013997:Time Factors
chemical_list: D013395:Sucrose; D009020:Morphine; D009269:Nalorphine