Specific mu 2 opioid isoreceptor regulation of nigrostriatal neurons: in vivo evidence with naloxonazine.
The irreversible mu 1 opiate antagonist, naloxonazine, totally blocked the analgesic actions (tail-flick assay) of morphine (8 mg/kg) in the rat. However, this treatment was without effect on the morphine-dependent (4 mg/kg) increases in striatal dopamine metabolism. These data support our previous studies which have suggested mu 2 and delta opioid receptor regulation of the rat nigrostriatal pathway.
D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects*; D004298:Dopamine / Q000378:metabolism; D008297:Male; D009020:Morphine / Q000494:pharmacology; D009270:Naloxone / Q000031:analogs & derivatives* / Q000494:pharmacology; D009619:Nociceptors / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D011930:Reaction Time / Q000187:drug effects; D011957:Receptors, Opioid / Q000187:drug effects*; D017450:Receptors, Opioid, mu; D013378:Substantia Nigra / Q000187:drug effects*
D011957:Receptors, Opioid; D017450:Receptors, Opioid, mu; D009270:Naloxone; D009020:Morphine; C034643:naloxonazine; D004298:Dopamine