Maitotoxin and Bay-K-8644: two putative calcium channel activators with different effects on endogenous dopamine...

In the present study we report on the effects of two putative calcium channel activators, maitotoxin and the dihydropyridine BAY-K-8644, on endogenous dopamine release from tuberoinfundibular dopaminergic neurons. Maitotoxin stimulated basal dopamine release and this effect was calcium-dependent. By contrast BAY-K-8644 failed to produce any modification of basal or high potassium-induced dopamine release. These results suggest that maitotoxin, unlike BAY-K-8644, represents a suitable tool to investigate the functional role of calcium channels in central dopaminergic neurons.