Figure 6.

Internal Na⁺, but not Cl⁻, suppresses the choline-induced current. A, Top row, NaGlu (46 nl of 0.5 m) was injected into LV-expressing oocytes. The final concentration of internal NaGlu is ∼23 mm NaGlu in oocytes, assuming a volume of 1 μl. The figure shows typical data in 10 μm choline before and 3 min after the injection, in oocytes held at −60 mV. A, Bottom row, LiCl (46 nl of 0.5 m) was injected into an LV-expressing oocyte. The final concentration of LiCl inside is ∼23 mm. Similar to A, the 10 μm choline-induced current was monitored at −60 mV before and 3 min after the injection. B, Summary. The effect of NaGlu and LiCl injections on choline-induced current. The currents are normalized to the current before injection (100 ± 10.6%; n = 4). Internal NaGlu reduced the induced current by 50% 3–5 min after the injection (56.0 ± 5.8%; n = 4). However, internal LiCl had almost no effect on the induced current (98.5 ± 9.5%; n = 4).