title: Analgesic properties of valproic acid might be related to activation of pro-enkephalin system in rat brain.
abstract: Recent in vivo and in vitro studies have shown the involvement of gamma-aminobutyric acid (GABA) in analgesia. We investigated if the analgesia induced by an acute valproic acid (VPA) administration might be related to the activation of the enkephalinergic system. VPA administration (i.p.) induces 30 min after treatment a significant and dose-dependent increase of Leu-enkephalin and Met-enkephalin in the striatum, hypothalamus, cortex and brainstem. In the hypophysis no modification was observed for these two neuropeptides. The Met-enkephalin-Arg-Gly-Leu levels are affected by VPA administration in a more complex pattern. Such results suggest the implication of an enkephalinergic system in GABAergic analgesia.
mesh_terms: D000700:Analgesics; D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects*; D004743:Enkephalin, Leucine / Q000378:metabolism*; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives / Q000378:metabolism*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D014635:Valproic Acid / Q000494:pharmacology*
chemical_list: D000700:Analgesics; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D014635:Valproic Acid; C033453:enkephalin-Met, Arg(6)-Gly(7)-Leu(8)-