Reversal of the actions of morphine on mesocortical dopamine metabolism in the rat by the kappa agonist MR-2034: tentative mu-2 opioid control of mesocortical dopaminergic projections.
Morphine was shown to enhance dopamine metabolism, as assessed by increased dihydroxyphenylacetic acid measurements, in the mesocortical dopaminergic projections of the rat (cingulate, pyriform and prefrontal cortices). In contrast, the kappa agonist MR-2034 did not alter dopamine metabolism but did antagonize the actions of morphine. Similar antagonism of the actions of morphine were noted in the striatum and olfactory tubercle. These data suggest that the mesolimbic and mesocortical dopaminergic projections may possess a mu-2 opioid receptor regulation as previously defined for the nigrostriatal pathway.
Kim
H S
HS
Pharmaceuticals Division, CIBA-GEIGY Corp., Summit, N.J. 07901.
Iyengar
S
S
Wood
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PL
D000818:Animals; D001575:Benzomorphans / Q000494:pharmacology*; D001921:Brain / Q000187:drug effects / Q000378:metabolism*; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D005625:Frontal Lobe / Q000187:drug effects / Q000378:metabolism; D006179:Gyrus Cinguli / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009019:Morphinans / Q000494:pharmacology*; D009020:Morphine / Q000494:pharmacology*; D009830:Olfactory Bulb / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000187:drug effects / Q000502:physiology*; D017450:Receptors, Opioid, mu
D001575:Benzomorphans; D009019:Morphinans; D011957:Receptors, Opioid; D017450:Receptors, Opioid, mu; C032478:MR 2034; D009020:Morphine; D004298:Dopamine