ABSTRACT
The effects of social deprivation on morphine consumption in C57BL/6J mice were investigated. Social or isolated animals (length of isolation: 7, 12, 17 days) were submitted to a free-choice between water and morphine hydrochloride solution (0.5 mg/ml). Isolation affects morphine consumption, with solitary housed mice drinking more morphine solution than socially housed animals. Moreover the amount of morphine intake depends on the duration of the isolation period to which mice are subjected. The importance of environmental factors on opiate consumption may be considered in terms of the possible implications of drug addiction in humans.
Subject(s)
Arousal/drug effects , Morphine Dependence/psychology , Social Isolation , Analysis of Variance , Animals , Drinking , Male , Mice , Mice, Inbred C57BL , Social Environment , Time FactorsABSTRACT
The two inbred strains of mice C57BL/6 and DBA/2 are characterized by a different behavioral reactivity to cholinergic agents during development. The present experiment revealed that the strain-dependent differences in cholinergic-mediated analgesia during development disappeared during adult life. In fact, oxotremorine administration (0.0025 and 0.005 mg/kg) exerted the same analgesic effect in both strains at 6 months of age, in contrast with the finding of the lack of any effect of the drug in C57 mice at two months of age in comparison with DBA.
Subject(s)
Aging/metabolism , Analgesia , Cholinergic Fibers/physiology , Mice, Inbred C57BL/metabolism , Mice, Inbred DBA/metabolism , Oxotremorine/pharmacology , Scopolamine/pharmacology , Animals , Cholinergic Fibers/drug effects , Male , Mice , Mice, Inbred C57BL/growth & development , Mice, Inbred C57BL/physiology , Mice, Inbred DBA/growth & development , Mice, Inbred DBA/physiology , Parasympathomimetics/pharmacologyABSTRACT
During development the C57BL/6 and DBA/2 mouse strains present morphological variations in cholinergic forebrain structures correlated with different behavioral reactivities to cholinergic agents. The present research assessed that these strain-dependent differences are also present in cholinergic-mediated analgesia. The administration of oxotremorine (0.0025, 0.005 and 0.01 mg/kg) to 30- and 60-day-old C57 and DBA mice resulted in dose- age- and strain-dependent analgesia. In particular oxotremorine is more effective in DBA/2 than in C57BL/6 mice and the latter strain showed a significant decrease of analgesic response in adulthood.
