Age-dependent sensitivity of cultured peripheral sympathetic neurons to 1-methyl-4-phenylpyridinium: role of glutathione

• Published in: Journal of neurochemistry Vol. 67; no. 2; p. 557
• Main Authors: Bhave, S V, Johannessen, J N, Lash, L H, Wakade, T D, Wakade, A R
• Format: Journal Article
• Language: English
• Published: England 01.08.1996
• Subjects: 1-Methyl-4-phenylpyridinium - toxicity; Adrenergic Fibers - drug effects; Age Factors; Animals; Biological Transport - drug effects; Cell Survival - drug effects; Cells, Cultured; Chick Embryo; Glutathione - metabolism; Neurotoxins - toxicity; Norepinephrine - metabolism; Sympathetic Nervous System - drug effects
• ISSN: 0022-3042
• DOI: 10.1046/j.1471-4159.1996.67020557.x

We demonstrate that 1-methyl-4-phenylpyridinium (MPP+) is toxic to chick peripheral sympathetic neurons maintained in culture in the presence of nerve growth factor (NGF). When MPP+ was added to the culture medium at the time the neurons were plated, cell loss after 3 days in culture was evident at concentrations as low as 3 nM, and near maximal at 1 microM. Toxicity was blocked by brief preincubation with the norepinephrine (NE)-reuptake blocker desipramine (DMI; 10 microM for 30 min). MPP+ blocked the uptake of [3H]NE by sympathetic neurons in a dose-dependent manner with a potency roughly equal to DMI. At concentrations up to 10 microM, MPP+ had no neurotoxic effect on the survival of sensory neurons maintained in the presence of NGF. The sensitivity of sympathetic neurons to the toxic effects of MPP+ diminished gradually with increasing lengths of time in culture. When MPP+ was added to the culture medium 48 h after plating, concentrations up to 100 microM did not cause neuronal death. This increasing resistance of sympathetic neurons to MPP+-induced cell death could not be explained by an increasing capacity for sequestration of MPP+ within synaptic vesicles. The loss of sensitivity with time in culture was, however, accompanied by a threefold increase in the levels of glutathione (GSH). Furthermore, addition of MPP+ (1 microM) to cultures previously maintained for 2 days in the presence of the GSH-synthesis inhibitor L-buthionine-[S,R]-sulfoximine (1 microM) caused the same degree of cell death as when added to freshly plated neurons. These results suggest that the observed toxicity of MPP+ in freshly plated chick sympathetic neurons may involve the formation of free radicals and that GSH plays a role in protecting sympathetic neurons in vivo from the toxicity of MPP+.