Biomaterial Database

Changes in fixed-interval behavior during chronic morphine treatment and morphine abstinence in rats. 1976

M Babbini, and M Gaiardi, and M Bartoletti

Rats previously trained to a fixed-interval schedule (FI 2 min) were treated twice daily with saline or morphine hydrochloride (final dose 40 mg/kg i.p.) for 44 days. On day 45 an abstinence state was induced by withdrawing morphine or by giving nalorphine (1 mg/kg i.p.). Operant behavior was recorded on alternate days during the period of chronic treatment and during the withdrawal phase (21 days). It was found that the number of lever presses decreased significantly during the first days of morphine administration but increased later over the control values. The quarter-life was not changed during this period. Morphine withdrawal and nalorphine treatment both caused a further increase in lever presses that lasted about 11 days. Again quarter-life was not changed. These results indicate that the effects of morphine on FI behavior in rats not only undergo tolerance but are actually reversed during the chronic treatment. The data obtained during the withdrawal phase are discussed in relation to the secondary abstinence syndrome described by Martin et al. (1963).

UI	MeSH Term	Description	Entries
D008297	Male		Males
D009020	Morphine	The principal alkaloid in opium and the prototype opiate analgesic and narcotic. Morphine has widespread effects in the central nervous system and on smooth muscle.	Morphine Sulfate,Duramorph,MS Contin,Morphia,Morphine Chloride,Morphine Sulfate (2:1), Anhydrous,Morphine Sulfate (2:1), Pentahydrate,Oramorph SR,SDZ 202-250,SDZ202-250,Chloride, Morphine,Contin, MS,SDZ 202 250,SDZ 202250,SDZ202 250,SDZ202250,Sulfate, Morphine
D009021	Morphine Dependence	Strong dependence, both physiological and emotional, upon morphine.	Morphine Abuse,Morphine Addiction,Abuse, Morphine,Addiction, Morphine,Dependence, Morphine
D009269	Nalorphine	A narcotic antagonist with some agonist properties. It is an antagonist at mu opioid receptors and an agonist at kappa opioid receptors. Given alone it produces a broad spectrum of unpleasant effects and it is considered to be clinically obsolete.	Allylnormorphine,Lethidrone,Nalorphine Hydrobromide,Nalorphine Hydrochloride,Nalorphine, (14 alpha)-Isomer,Nalorphine, L-tartrate (1:1),Hydrobromide, Nalorphine,Hydrochloride, Nalorphine
D012055	Reinforcement Schedule	A schedule prescribing when the subject is to be reinforced or rewarded in terms of temporal interval in psychological experiments. The schedule may be continuous or intermittent.	Reinforcement Schedules,Schedule, Reinforcement,Schedules, Reinforcement
D001835	Body Weight	The mass or quantity of heaviness of an individual. It is expressed by units of pounds or kilograms.	Body Weights,Weight, Body,Weights, Body
D003216	Conditioning, Operant	Learning situations in which the sequence responses of the subject are instrumental in producing reinforcement. When the correct response occurs, which involves the selection from among a repertoire of responses, the subject is immediately reinforced.	Instrumental Learning,Learning, Instrumental,Operant Conditioning,Conditionings, Operant,Instrumental Learnings,Learnings, Instrumental,Operant Conditionings
D004361	Drug Tolerance	Progressive diminution of the susceptibility of a human or animal to the effects of a drug, resulting from its continued administration. It should be differentiated from DRUG RESISTANCE wherein an organism, disease, or tissue fails to respond to the intended effectiveness of a chemical or drug. It should also be differentiated from MAXIMUM TOLERATED DOSE and NO-OBSERVED-ADVERSE-EFFECT LEVEL.	Drug Tolerances,Tolerance, Drug,Tolerances, Drug
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia