Effects of morphine and B-endorphin on Ca2+-ATPase activity of synaptic plasma membranes.
Morphine and B-endorphin were found to inhibit the high calcium -affinity Ca2+-ATPase of synaptic plasma membranes which is believed to be involved in the regulation of intracellular Ca2+ that triggers the release of neurotransmitters. The inhibition was blocked by naloxone and reversed by calmodulin. Kinetic analyses revealed that opioids decreased the affinity of Ca2+-ATPase for Ca2+ and calcium bound to the enzyme decreased the affinity of the enzyme for opioids.
D000818:Animals; D001921:Brain / Q000201:enzymology*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009020:Morphine / Q000494:pharmacology*; D013570:Synaptic Membranes / Q000201:enzymology*; D013574:Synaptosomes / Q000201:enzymology; D001615:beta-Endorphin / Q000494:pharmacology*
D001615:beta-Endorphin; D009020:Morphine; D000252:Calcium-Transporting ATPases