Implication of alterations in intracellular calcium ion homoeostasis in the advent of paracetamol-induced cytotoxicity in primary mouse hepatocyte monolayer cultures.

We have examined the fluctuation of free cytoplasmic Ca(2+) concentration ([Ca(2+)](i)) using the fluorescent probe quin-2 during the cytotoxic response induced by low concentrations (100-250 mum) of the model hepatotoxin paracetamol (APAP) in primary mouse hepatocyte cultures over 5 days. APAP-associated increases in [Ca(2+)](i) were recorded prior to APAP-associated cytotoxicity, and correlated with the subsequent loss of cell viability as measured by intracellular lactate dehydrogenase and K(+) efflux. Co-incubation with promethazine (1 mum) or ethyleneglycol-bis-(beta-aminoethyl ether)-N,N,N',N'-tetraacetic 0215 acid (4 mm) attenuated both the APAP-associated [Ca(2+)](i) changes and cytotoxicity. These results support the hypothesis that mobilization of intracellular Ca(2+) may be an important early event in APAP-induced hepatotoxicity.