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Nitric oxide activation of poly(ADP-ribose) synthetase in neurotoxicity
J Zhang1, V L Dawson, T M Dawson
1Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
Abstract:
Poly(adenosine 5'-diphosphoribose) synthetase (PARS) is a nuclear enzyme which, when activated by DNA strand breaks, adds up to 100 adenosine 5'-diphosphoribose (ADP-ribose) units to nuclear proteins such as histones and PARS itself. This activation can lead to cell death through depletion of beta-nicotinamide adenine dinucleotide (the source of ADP-ribose) and adenosine triphosphate. Nitric oxide (NO) stimulated ADP-ribosylation of PARS in rat brain. Benzamide and other derivatives, which inhibit PARS, blocked N-methyl-D-aspartate- and NO-mediated neurotoxicity with relative potencies paralleling their ability to inhibit PARS. Thus, NO appeared to elicit neurotoxicity by activating PARS.