kappa-opioid agonist stimulated regional distribution of [(35)S]GTPgammas binding in butorphanol continuously infused rat.

Article Details

Citation

Copy to clipboard

Park Y, Jang CG, Ho IK, Ko KH

kappa-opioid agonist stimulated regional distribution of [(35)S]GTPgammas binding in butorphanol continuously infused rat.

Brain Res Bull. 2000 May 1;52(1):17-20.

PubMed ID

10779697 [ View in PubMed

]

Abstract

Butorphanol is a mixed agonist/antagonist opioid analgesic agent, which exerts its effects mainly by interaction with the kappa-opioid receptor. Opioid receptors are coupled to G proteins of G(i)/G(o) family, and recently a decrease in micro-opioid activation of G proteins has been reported in specific brainstem nuclei after chronic morphine administration. The influence of centrally administered butorphanol on agonist-stimulated G protein coupling was examined in the rat brain, using in situ guanylyl-5'-O-(gamma-[(35)S]thio)-triphosphate (GTPgammaS) binding autoradiography. Rats were treated with butorphanol (26 nmol/microl/h) by intracerebroventricular infusion via osmotic minipumps for 3 days. The distribution of [(35)S]GTPgammaS binding in the brain 7 h after the termination of butorphanol infusion was measured in the presence or absence of the selective kappa-opioid agonist, U-50,488. This agonist significantly increased [(35)S]GTPgammaS binding in the parietal cortex, caudate putamen, thalamus, and central gray of control rats, but not in those regions of the butorphanol-infused animals. These results suggest that chronic administration of butorphanol developed tolerance and abolished U-50,488 activation of G proteins in these brain areas.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Butorphanol	Kappa-type opioid receptor	Protein	Humans	Yes	Agonist	Details