Taurine inhibits cellular hemichannel function. Calcein uptake by cells expressing connexin hemichannels was assessed by incubation with extracellular calcein in low Ca2+ medium (Goldberg et al., 1995; Li et al., 1996). (A) Dye uptake correlated with doxycycline-induced expression of connexin (Cx32T in this illustration). Similar induction of dye uptake was observed for all cell lines used (n = 3). (B) Effects of extracellular AS on dye uptake by cells expressing the various connexin channels (extracellular taurine enters cells via a taurine transporter; Ramamoorthy et al., 1994) (n = 3). Only channels in which the Cx26 subunits are not tagged were AS sensitive, corresponding to the results from the liposome-based TSF study (Fig. 1). The results for each experimental condition with taurine were normalized to its own control experiment without taurine. Error bars are standard errors of the mean.
