MPP+ selectively affects calcium homeostasis in mesencephalic cell cultures from embryonal C57/B16 mice

Abstract

1-Methyl-4-phenylpyridinium (MPP⁺), the active metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) serves as a valuable tool in animal models of Parkinson's disease. Primary cell cultures of mesencephalon from C57/B16 mice were used to investigate the effects of various dopaminergic neurotoxins on the intracellular calcium metabolism. MPP⁺ was compared to its precursor MPTP and a structural analogue paraquat (methylviologen). Direct addition of these neurotoxins (10 μM) to fura-2-labeled cells did not change intracellular calcium concentrations in the presence of 1 mM extracellular calcium. When mesencephalic neurons were exposed to the compounds for 24 hours, only MPP⁺ led to an increase in calcium concentration in the absence and presence of extracellular calcium (36%, p+ is shown to selectively increase intracellular calcium concentrations in mesencephalic cultures.