Figure 3.

GABA_BR-mediated increases in outward HCs are mediated by activation of K_2P channels. A, Bath application of baclofen induced a small inward current when Cs⁺-gluconate-containing intracellular solution was used in contrast to baclofen-induced outward currents when the intracellular solution contained K⁺-gluconate. B, Voltage-current relationship induced by a ramp protocol from −140 mV to 0 mV at a speed of 0.1 mV/ms prior to and during the application of baclofen. Subtraction of the current prior to the application of baclofen generated a net current of outward rectification (inset). The traces were averages from 9 cells. Note that the reversal potential was ~ −90.1 mV, close to the calculated K⁺ reversal potential (−92.2 mV). C, Baclofen-induced increases in outward HCs were insensitive to extracellular application of TEA, 4-AP, Cs⁺ and tertiapin, but reduced when the extracellular K⁺ concentration was increased to 10 mM (* p=0.02). D, Inclusion of Ba²⁺ in the extracellular solution induced an inward HC, but significantly reduced baclofen-induced increases in outward HCs.