The effects of morphine and methionine-enkephalin on the release of purines from cerebral cortex slices of rats and mice.
1 Slices of cerebral cortex from Wistar rats, TO mice or C57 mice were preincubated with [3H]-adenosine, and labelled purines were subsequently releases by electrical stimulation or by perfusing with ouabain, 100 micro M. 2 Electrically-evoked purine release was substantially reduced when the Ca2+ concentration in the medium was lowered from 2.4 to 0.1 mM. In both rats and mice, the electrically-evoked release was increased by morphine and methionine-enkephalin (Met-enkephalin), 10 micro M, and in rats and TO mice by morphine 1 micro M, both drug effects being prevented by naloxone. 3 Purine release evoked by ouabain was also increased by morphine 1 and 10 micro M, though not by Met-enkephalin, from slices of rat cortex. Ouabain-induced release from TO mice was reduced by morphine, and from C57 mice was unchanged. 4 The enhancement by morphine of electrically-evoked purine release may indicate that purines mediate some effects of morphine in the CNS.
D000818:Animals; D002118:Calcium / Q000502:physiology; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D004558:Electric Stimulation; D004723:Endorphins / Q000494:pharmacology*; D004744:Enkephalin, Methionine; D004745:Enkephalins / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D009020:Morphine / Q000494:pharmacology*; D010042:Ouabain / Q000494:pharmacology; D011684:Purine Nucleosides / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D004723:Endorphins; D004745:Enkephalins; D011684:Purine Nucleosides; D004744:Enkephalin, Methionine; D010042:Ouabain; D009020:Morphine; D002118:Calcium