title: The specific opioid kappa-agonist U-50,488H inhibits low Km GTPase.
abstract: DAGO, a specific opioid mu-agonist stimulated the low Km GTPase activity of membranes of the guinea-pig striatum at 1-1000 nM and this effect was antagonized by naloxone 10-100 nM. On the other hand, U-50,488H, a specific opioid kappa-agonist inhibited the low Km GTPase activity of membranes of the guinea-pig cerebellum at 1-100 nM. As this effect was antagonized by MR2266 but not by naloxone, the findings suggest that opioid mu- and kappa-receptor stimulation is probably linked to the stimulation and inhibition of low Km GTPase, respectively.
mesh_terms: D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D001575:Benzomorphans / Q000494:pharmacology; D002531:Cerebellum / Q000201:enzymology / Q000378:metabolism; D003342:Corpus Striatum / Q000201:enzymology / Q000378:metabolism; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004745:Enkephalins / Q000494:pharmacology; D020558:GTP Phosphohydrolases / Q000037:antagonists & inhibitors*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D009292:Narcotic Antagonists / Q000494:pharmacology; D010744:Phosphoric Monoester Hydrolases / Q000037:antagonists & inhibitors*; D011759:Pyrrolidines / Q000494:pharmacology*; D011957:Receptors, Opioid / Q000378:metabolism*; D017473:Receptors, Opioid, kappa
chemical_list: D000700:Analgesics; D001575:Benzomorphans; D004745:Enkephalins; D009292:Narcotic Antagonists; D011759:Pyrrolidines; D011957:Receptors, Opioid; D017473:Receptors, Opioid, kappa; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; C027247:MR 2266; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D010744:Phosphoric Monoester Hydrolases; D020558:GTP Phosphohydrolases