Figure 1.

Activation of an inward current in whole cells by AlCl₃. Results are shown from two experiments which included either KCl (a–d) or TEACl (e–h) in the solutions. Whole-cell currents, I_m, were recorded as V_m was stepped from a holding potential near 0 mV in 20-mV intervals to the levels shown (to the right of the current traces). Plots a–c and e–g represent a sequence of solution changes. The control solution shown in a comprised 1 mM KCl and 0.2 mM CaCl₂, pH 4.0. The control solution shown in e contained 20 mM TEACl and 0.2 mM CaCl₂, pH 4.0. Similar solutions containing 50 μM AlCl₃ were added in b and f, and the currents were recorded after the time indicated. AlCl₃ was then removed by changing to the control solution again as shown in c and g. Currents measured at the end of the voltage pulses were used to construct the current–voltage curves shown in d and h. The pipette solution for a–d was (mM) 90 KCl, 7.6 CaCl₂, 10 EGTA, 10 Hepes, and 48 KOH to pH 7.2. The pipette solution for e–h was (mM) 100 TEACl, 2 MgCl₂, 10 Hepes, 2 EGTA, 2 Na₂ATP, and 20 TEAOH to pH 7.2.