Modulation of glutamate release by a kappa-opioid receptor agonist in rodent and primate striatum

The influence of the kappa-opioid receptor agonist, enadoline, on endogenous glutamate release was investigated in rat and marmoset striatal synaptosomes. Enadoline decreased 4-aminopyridine (2 mM)-stimulated glutamate release (rat: IC50 approximately 8.7 microM, marmoset: IC50 approximately 2.9 microM). The effect of enadoline was reversed by nor-binaltorphimine (5 microM). These data indicate that, in the striatum of the rat and marmoset, kappa-opioid receptor agonists can modulate glutamate release. These findings may have implications for the treatment of Parkinson's disease.