Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0278080 (physical dependence)
 1,658 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have previously shown that the antinociceptive effects produced by the delta opioid-selective agonist deltorphin II are preserved in mu-opioid receptor (MOR)-deficient mice. We have now investigated rewarding effects and physical dependence produced by deltorphin II in these animals. Wild-type and MOR-deficient mice were implanted with a cannula into the third ventricle and deltorphin II was administered centrally. The rewarding effects induced by deltorphin II were then investigated using the place preference paradigm. Wild-type mice showed place preference for the compartment previously associated with deltorphin II and this effect was not observed in MOR-deficient mice. In a second experiment, mice received a chronic perfusion of deltorphin II over 6 days, via an Alzet minipump connected to the intraventricular cannula, and withdrawal was precipitated by naloxone administration. Wild-type animals showed a moderate but significant incidence of several somatic signs of withdrawal. This withdrawal response was suppressed in MOR-deficient mice. Analysis of the immunoreactivity levels of PKC-alpha, PKC-beta (I and II) and PKC-gamma isozymes in the cerebral cortex of mice infused chronically with deltorphin II showed a significant up-regulation of all these isozymes in the soluble fraction in wild-type but not in MOR-deficient mice. In conclusion, mu-opioid receptors, which are not involved in deltorphin II antinociception, appear to mediate the effects of chronic deltorphin II on rewarding responses, physical dependence and adaptive changes to PKC.
 ...
PMID:Lack of dependence and rewarding effects of deltorphin II in mu-opioid receptor-deficient mice. 1113 13