Enkephalins affect hippocampal membrane phosphorylation.
Slices of rat brain hippocampus were incubated with methionine-enkephalin, leucine-enkephalin, [Des-Tyr1] methionine-enkephalin or etorphin. After incubation the endogenous phosphorylation of proteins was measured using crude mitochondrial fractions prepared from the incubated slices. Methionine- and leucine-enkephalin specifically enhanced the radiophosphate incorporation into one protein band with an apparent molecular weight of 50K. The effect could also be detected in a fraction containing purified synaptosomal plasma membranes. The effect was time- and dose-dependent and could be mimicked by etorphin and blocked by naloxone. If methionine-enkephalin was added directly to a membrane fraction a marked inhibition of incorporation of phosphate into the 50K band was observed. It is suggested that opiate-receptor activation underlies the effects of enkephalin on hippocampal phosphoprotein metabolism.
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D004723:Endorphins / Q000494:pharmacology*; D004745:Enkephalins / Q000494:pharmacology*; D005048:Etorphine / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D008566:Membranes / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D008970:Molecular Weight; D009270:Naloxone / Q000494:pharmacology; D010766:Phosphorylation; D051381:Rats; D013574:Synaptosomes / Q000378:metabolism
D004723:Endorphins; D004745:Enkephalins; D009270:Naloxone; D005048:Etorphine