Involvement of Ca2+ in dopamine release in striatal rat slices by PF9601N and L-deprenyl

Rat striatal slices were incubated 1 hour in Krebs buffer with carbogen by continuous perfusion. When both MAO-B inhibitors PF9601N and l-deprenyl were added in the incubation medium, at 200 microM concentration, a diminution in the dopamine content was observed. The decrease in dopamine content was partially calcium dependent and showed a different mechanism between both compounds. When 1 mM concentration EGTA was added at the Krebs incubation medium without calcium, dopamine content was partially recovered, being not affected in case of l-deprenyl. When 50 microM dantrolene (a calcium vesicular release inhibitor) was added in the Krebs incubation medium without calcium, dopamine was partially recovered for l-deprenyl, being not affected in case of PF9601N. These data indicate that dopamine release is extracellular calcium dependent in case of PF9601N, whereas l-deprenyl depends on calcium intracellular origin.