BARAKOL, A NATURAL ANXIOLYTIC, INHIBITS STRIATAL DOPAMINE RELEASE BUTNOT UPTAKE IN-VITRO

The present study investigated the effects of barakol on the in vitro release of endogenous and radiolabelled dopamine from rat striatal sli ces in comparison with the dopamine receptor agonists, quinelorane dih ydrochloride (1 mu M) and pergolide methanesulfonate (100 mu M), and t he dopamine receptor antagonist, S(-)-eticlopride hydrochloride (10 mu M) using a semi-superfusion method and high-performance liquid chroma tography with electrochemical detector measurement of endogenous dopam ine. Barakol (1, 10 and 100 mu M) reduced K+-stimulated endogenous dop amine release as did the dopamine D-2 receptor agonists but had no eff ect on [H-3]dopamine release. The inhibition of barakol (10 mu M) on K +-stimulated endogenous dopamine release was antagonised by a dopamine D-2 receptor antagonist, eticlopride. Barakol (0.1 nM-10 mu M) had no effect on [H-3]dopamine uptake except at the highest concentration (1 00 mu M) when inhibition was observed. The results indicate that barak ol might act as a dopamine agonist to inhibit endogenous dopamine rele ase without a change in dopamine uptake.