Figure 7.
Current properties of TMEM16A and TMEM16B cloned from rat pinealocytes. A–F, rat TMEM16A (3 μg), TMEM16B (3 μg), or TMEM16A + TMEM16B (1 + 2 μg) cDNA was transfected into HEK293 cells. HEK293 cells were depolarized from the holding potential of −40 mV to test potentials (−80 ∼ +100 mV) by +20 mV increment for 500 ms and subsequently repolarized to −80 mV for 250 ms every 15 s. Representative traces of ClCa currents and their current-voltage relationships at pCa 7.0, 6.5, and 6.0 in the pipette solution from HEK293 cells expressing TMEM16A (A and B), TMEM16B (C and D), or TMEM16A + TMEM16B (E and F). G, outward current density at +100 mV at pCa 6.5. H, τact of outward currents in pinealocytes and HEK293 cells transfected with TMEM16A, TMEM16B, TMEM16A + TMEM16B (1:1), TMEM16A + TMEM16B (1:2), or TMEM16B–TMEM16A tandem form. I, τtail of tail currents. Note that the predominant electrophysiological properties of pinealocytes are very similar to these of TMEM16A/TMEM16B (1:2) co-expressing HEK293 cells. Data from pinealocytes have been replotted from Fig. 2. Experimental data were obtained from 4 to 8 cells.