Dual effect of verapamil on K+-evoked release of endogenous dopamine from arcuate nucleus-median eminence complex.
The effect of verapamil, a calcium-entrance blocker, on K+-evoked release of endogenous dopamine from tuberoinfundibular neurons incubated in vitro was studied. This compound, added to the incubation medium, at the dose of 10(-6) M, significantly reinforced K+-induced dopamine release, whereas, at higher doses (10(-5), 5 X 10(-5) and 10(-4) M), it completely prevented the stimulated dopamine release. The results obtained with the higher doses showed the calcium dependence of K+-evoked release of endogenous dopamine from central neurons. The opposite effect, seen with the lower dose of verapamil, could be due to different pharmacological properties of the drug.
D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D004347:Drug Interactions; D005260:Female; D008473:Median Eminence / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D014700:Verapamil / Q000008:administration & dosage / Q000494:pharmacology*
D014700:Verapamil; D011188:Potassium; D004298:Dopamine