title: Opiates stimulate low Km GTPase in brain.
abstract: Low Km GTP hydrolysis in rat brain is stimulated in a concentration-dependent manner by the opiate alkaloid etorphine, and by the opioid peptide D-Ala2-leucine-enkephalinamide. The opiate antagonist naloxone inhibits the maximal D-Ala2-leucine-enkephalinamide stimulation of the GTPase, also with concentration dependency. The magnitude of maximally stimulated, opioid-sensitive, GTP hydrolysis is differentially distributed across brain regions. Opioid-stimulated GTPase may represent one means of identifying a specific type of opioid receptor.
mesh_terms: D000067956:Adenylyl Cyclase Inhibitors; D000818:Animals; D001921:Brain / Q000201:enzymology*; D004723:Endorphins / Q000494:pharmacology*; D004743:Enkephalin, Leucine / Q000031:analogs & derivatives / Q000494:pharmacology; D016308:Enkephalin, Leucine-2-Alanine / Q000031:analogs & derivatives*; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives / Q000494:pharmacology; D005048:Etorphine / Q000494:pharmacology; D020558:GTP Phosphohydrolases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution
chemical_list: D000067956:Adenylyl Cyclase Inhibitors; D004723:Endorphins; D009270:Naloxone; D005048:Etorphine; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; C013801:enkephalin-Met, Ala(2)-; D016308:Enkephalin, Leucine-2-Alanine; C030279:enkephalinamide-Leu, Ala(2)-; D006160:Guanosine Triphosphate; D010744:Phosphoric Monoester Hydrolases; D020558:GTP Phosphohydrolases