Met-enkephalin selectively increases the spontaneous release of amino acid neurotransmitters from rat striatal slices.
Met-enkephalin (1 microM) increased the spontaneous release of endogenous glutamate (+155%), taurine (+80%) and glycine (+50%) from rat striatal slices, but was without effect in the cerebral cortex. This effect was calcium-dependent and significantly reduced in the presence of naloxone (1 microM). Naloxone alone had no effect on release of any substance. Release of aspartate, gamma-aminobutyric acid and [3H]acetylcholine was not significantly affected. Met-enkephalin did not affect potassium (35 mM)-evoked neurotransmitter release, nor did it affect the uptake of D-[3H]aspartate, [3H]taurine or [14C]glycine. The data indicate that opioid receptor activation selectively increases the spontaneous calcium-dependent release of putative amino acid neurotransmitters in the rat striatum.
Arnerić
S P
SP
Meeley
M P
MP
Reis
D J
DJ
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003342:Corpus Striatum / Q000378:metabolism*; D004744:Enkephalin, Methionine / Q000494:pharmacology*; D008297:Male; D018377:Neurotransmitter Agents / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D000596:Amino Acids; D018377:Neurotransmitter Agents; D004744:Enkephalin, Methionine