Previous spatial learning is required for the development of place preference in rats following chronic administration of and withdrawal from morphine

摘要: The positive reinforcing properties of addictive drugs have a primary role in the development drug dependence. In field opiates, great attention has been given to this phenomenon, as well negative eliciting craving and inducing relapse during withdrawal. This study was designed evaluate whether elevated plus-maze (EPM) experienced rats withdrawn from low doses subcutaneous (s.c.) morphine (10 mg/kg), which high anxiety level is most prominent withdrawal symptom, acquire place preference when submitted conflict paradigm effects are paired with an aversive context: distal part open arms EPM. Both test conditioning were measured same apparatus, biased version plus-maze. order verify influence previous EPM spatial learning on performance morphine-withdrawn rats, half animals prior treatment. Additional groups also tested under effects. treatments quantified through analysis three types measures: inferred use conventional measures (percentage entries time spent open-arms) risk-assessment behaviours (frequency stretched-attending postures - SAP, at centre maze). Place evaluated number entries, total distance run open-arm extremities, where conditioned. closed-arm taken index locomotor activity. Our results showed that (i) naive pre-treated did not develop preference, behaving like control rats; (ii) had experience no changes avoidance second exposure, compared for condition; (iii) contextual cues was, fact, requirement anxiety-inducing open-arms and, (iiii) conditioned achieved both withdrawal, probably or promoted by presence absence central nervous system.