The effects of methylmercury on endogenous dopamine efflux from mouse striatal slices.
The present study investigated the effects of in vitro methylmercury (MeHg) exposure on endogenous dopamine (DA) efflux from mouse striatal slices. MeHg produced a concentration-dependent increase in the spontaneous efflux of DA which was independent of the availability of Ca2+ in the superfusion medium. The Ca(2+)-dependent K(+)-evoked release of DA was significantly enhanced by 50 and 100 microM MeHg. This increase could not be solely accounted for by the MeHg-induced increased in spontaneous DA efflux. The K(+)-stimulated efflux of DA was enhanced by MeHg in both the presence and absence of Ca2+ in the superfusion medium, suggesting that under depolarizing conditions, DA efflux induced by MeHg has a Ca(2+)-independent component. The alterations in DA efflux occurred at concentrations of MeHg previously found in the CNS of animals exhibiting symptoms of MeHg intoxication suggesting that alterations in DA neurotransmission in the striatum may contribute to the symptoms of MeHg toxicity.
Kalisch
B E
BE
Department of Pharmacology and Toxicology, Queen's University, Kingston, Ontario, Canada.
Racz
W J
WJ
D000818:Animals; D000252:Calcium-Transporting ATPases / Q000187:drug effects / Q000378:metabolism; D003342:Corpus Striatum / Q000187:drug effects* / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D017506:H(+)-K(+)-Exchanging ATPase / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D008767:Methylmercury Compounds / Q000633:toxicity*; D051379:Mice
D008767:Methylmercury Compounds; D017506:H(+)-K(+)-Exchanging ATPase; D000252:Calcium-Transporting ATPases; D004298:Dopamine