Figure 10.

Facilitating and shunting actions of GABA in CR cells. Whole-cell recordings of membrane potential (black traces) in response to current injection of increasing intensities (gray traces). Current pulses were injected simultaneously with the GABA application (left traces), at the peak (middle traces), or in the decaying phase (right traces) of the GABA-induced membrane depolarization (triangles). A, At a [Cl⁻]_p of 30 mm, GABA decreased the threshold current to evoke APs, independent of the timing between current injection and GABA application. In addition, the number of APs increased, compared with current injection without GABA application. B, At a [Cl⁻]_p of 10 mm, GABA increased the threshold current to evoke APs and decreased the number of APs independent of the timing between current injection and GABA application.