The NT contributes to the difference in the sensitivity of Cx46 and Cx50 hemichannels to BQ⁺. Concentration–response curves for the inhibition of macroscopic hemichannel currents in oocytes expressing Cx50 wt (closed squares), Cx46 wt (closed circles), Cx46*50NT (open squares), and Cx50*46NT (open circles). Oocytes were voltage clamped at −70 mV. Current magnitude in oocytes expressing Cx46*50NT, in which Cx46 NT sequence was replaced with that of Cx50, was substantially reduced by 0.5 mM to 3 mM BQ⁺. The reciprocal chimera, Cx50*46NT, was similar to Cx46 in being largely insensitive to BQ⁺ at all concentrations except 3 mM. Each point represents the mean ± SEM from four different oocytes