Fig. 4.

Inhibition of fast zinc toxicity by pyruvate or niacinamide. Neuronal cultures were exposed to 100 μmZn²⁺ for 15 min or 400 μmZn²⁺ for 5 min in the presence or absence of 60 mm KCl, with 10 mm pyruvate or 10 mm niacinamide present 1 hr before, during, and 24 hr afterwards as indicated. Neuronal death was determined 24 hr after the onset of Zn²⁺ exposure by LDH efflux (n = 9–12 cultures per condition). *p < 0.05 signifies difference from Zn²⁺ exposure alone. #p < 0.05 signifies difference associated with pyruvate or niacinamide addition on neuronal death induced by Zn²⁺ plus KCl.