Electric properties of rat liver cell cultures on gas-permeable membranes

In rat hepatocytes grown on gas-permeable membranes (Petzinger et al. In Vitro Cell. Dev. Biol. 24: 491-499, 1988), cellular and canalicular potentials as well as input resistances were measured using two-channel microelectrodes. In HCO3(-)-containing solutions, we found -30.9 +/- 0.4 (SE) (n = 141) and -13.9 +/- 1.4 mV (n = 22) for cell and canalicular membrane potentials, respectively. There was no dependence of these parameters on the age of the primary culture. Canalicular input resistance, however, increased from 13.3 +/- 2.0 M omega (n = 4) at day 1 after seeding to 36.1 +/- 5.0 M omega (n = 9) at day 2 and stabilized thereafter, while cell input resistance continuously decreased from 37.0 +/- 3.3 M omega at 1 h (n = 6) to 5.2 +/- 2.1 M omega (n = 27) at 3 days after preparation. In ion substitution experiments there were no changes in the transference numbers for K+, Na+, or Cl- that could account for this effect. Cable analysis, however, revealed that the decrease in input resistance reflects a time-dependent increase in electrical coupling between cells. We conclude that rat liver cells on gas-permeable membranes are highly suited for the quantitative analysis of cell-to-cell interaction. In addition, cells and canaliculi are readily accessible with two-channel microelectrodes, making this preparation a promising tool for electrophysiological analysis of hepatocellular transport mechanisms.