[Transport of calcium to synaptosomes and subcellular membrane fractions of the brain: effects of opioid peptides].
Highly purified synaptosomal and subcellular fractions identified as mitochondria and microsomes were obtained by fractionation of brain tissues. The greatest Ca-accumulating capacity and the highest rate of Ca2+ accumulation were revealed in the mitochondrial fraction. Upon further fractionation of the synaptosomal fraction the energy-dependent uptake (accumulation) of Ca2+ was revealed only in the mitochondria. It was demonstrated that opioid peptides accelerate Ca2+ uptake by the synaptosomes in a medium with physiological concentration of K+ and inhibit this process during K+-dependent membrane depolarization. It was shown that beta-endorphine, methionine-encephaline and leucine-encephaline (10(-8)-10(-5) M) inhibit the Ca-accumulating capacity of both mitochondria and microsomes from brain. The experimental data suggest that opioid peptides can modulate the release of neurotransmitters and/or neurohormones by inhibiting the potential-dependent Ca2+ influx into the nerve endings and by decreasing the intrasynaptosomal pool of Ca2+.
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D001921:Brain / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D004723:Endorphins / Q000494:pharmacology*; D004743:Enkephalin, Leucine / Q000494:pharmacology*; D004744:Enkephalin, Methionine / Q000494:pharmacology*; D007425:Intracellular Membranes / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008861:Microsomes / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D051381:Rats; D013574:Synaptosomes / Q000187:drug effects / Q000378:metabolism*; D001615:beta-Endorphin
D004723:Endorphins; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D001615:beta-Endorphin; D002118:Calcium
Transport kal'tsiia v sinaptosomy i subkletochnye membrannye fraktsii golovnogo mozga: vliianie opioidnykh peptidov.