Effects of pentazocine and concomitant clonidine on opioid receptors in the rat brain.
The changes in opioid receptors (Op-R) caused by repeated administration of pentazocine and the effect of concomitant clonidine were investigated. Binding of [3H] naloxone was markedly decreased in the absence of Na+, but was increased in the presence of Na+ in the diencephalon-mesencephalon of chronic pentazocine-treated rats. No significant changes were observed in the cerebral cortex of pentazocine-treated rats. The pentazocine-induced changes in Op-R were abolished by the concurrent use of clonidine, an alpha-adrenergic agonist, which has been shown to relieve the withdrawal symptoms of morphine. This result indicated that the behavioral action of clonidine can also be observed at the Op-R level.
Ogawa
N
N
Hirose
Y
Y
Kuroda
H
H
Takayama
H
H
D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D003000:Clonidine / Q000494:pharmacology*; D006801:Humans; D008297:Male; D009270:Naloxone / Q000378:metabolism; D009293:Opioid-Related Disorders / Q000188:drug therapy; D010423:Pentazocine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000187:drug effects* / Q000378:metabolism; D012964:Sodium / Q000494:pharmacology
D011957:Receptors, Opioid; D009270:Naloxone; D012964:Sodium; D003000:Clonidine; D010423:Pentazocine