mu-Opposing actions of the kappa-opioid receptor.
Pharmacological studies and recent research using genetic approaches have indicated that most actions of exogenous opioids, such as morphine, are mediated through the mu-opioid receptor. By contrast, the function of the kappa-opioid receptor in opioid actions largely remains unclear. In this article, Zhizhong Z. Pan discusses the accumulating evidence that activation of the kappa-receptor antagonizes various mu-receptor-mediated actions in the brain, including analgesia, tolerance, reward and memory processes. The neural mechanism for this potentially ubiquitous mu-opposing function of the kappa-receptor is believed to involve distinct locations of the two opioid receptors on physiologically different cell types in local neuronal networks that are implicated in an opioid action.
Pan
Z Z
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Department of Neurology, University of California, San Francisco 94143, USA.
D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D006801:Humans; D017473:Receptors, Opioid, kappa / Q000187:drug effects / Q000502:physiology*; D017450:Receptors, Opioid, mu / Q000187:drug effects / Q000502:physiology*
D000701:Analgesics, Opioid; D017473:Receptors, Opioid, kappa; D017450:Receptors, Opioid, mu