Age-dependent sensitivity of cultured peripheral sympathetic neurons to 1-methyl-4-phenylpyridinium: role of glutathione.
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+.
Bhave
S V
SV
Department of Pharmacology, WSU School of Medicine, Detroit, Michigan 48201, USA.
Johannessen
J N
JN
Lash
L H
LH
Wakade
T D
TD
Wakade
A R
AR
D015655:1-Methyl-4-phenylpyridinium / Q000633:toxicity*; D000320:Adrenergic Fibers / Q000187:drug effects; D000367:Age Factors; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002642:Chick Embryo; D005978:Glutathione / Q000378:metabolism*; D009498:Neurotoxins / Q000633:toxicity*; D009638:Norepinephrine / Q000378:metabolism; D013564:Sympathetic Nervous System / Q000187:drug effects*
D009498:Neurotoxins; D005978:Glutathione; D015655:1-Methyl-4-phenylpyridinium; D009638:Norepinephrine