Table 2.

Zinc exposure decreased NAD⁺, and this effect was reversed by addition of pyruvate or niacinamide

Condition	NAD+ (nmol/plate)	NADH (nmol/plate)	Lactate (nmol/plate)
Control	4.63  ± 0.31	0.58  ± 0.052	2020  ± 130
Control + 4 mm pyruvate	5.62  ± 0.59*	0.20  ± 0.016*	2930  ± 110*
Control + 1 mmniacinamide	6.170  ± 0.36*	0.66  ± 0.058	2650  ± 230*
40 μm Zinc	1.36  ± 0.16*	0.83  ± 0.14	2470  ± 80*
40 μm Zinc + 4 mm pyruvate	4.86  ± 0.22#	0.042  ± 0.027#	3600  ± 140#
40 μm Zinc + 1 mmniacinamide	4.38  ± 0.40#	0.89  ± 0.059	3270  ± 170#

Neuronal cultures (6 × 10⁶ cells per plate) were sham-washed (Control) or exposed to 40 μmZn²⁺ in the presence or absence of 4 mmpyruvate or 1 mm niacinamide for 4 hr, after which the cells were harvested and assayed for levels of NAD⁺, NADH, or extracellular lactate (results are pooled from three separate experiments; n = 5–8 cultures per condition). * signifies difference from sham-washed controls at p < 0.05 by two-way ANOVA, followed by a Bonferroni test.

signifies difference from Zn²⁺-treated cultures at p < 0.05.