Fig. 8.

Effects of Ba²⁺ on membrane properties and on 1S,3R-ACPD-induced inward current.A, Membrane I–V relationships before and after perfusion with Ba²⁺ (2 mm).V_m, −70 mV. Note that Ba²⁺ induced an inward current at resting membrane potential (−70 mV) and reduced the slope of theI–V plot. G_N, Membrane input conductance. B, I–V relationship for the Ba²⁺-induced inward current with a reversal potential at approximately −93 mV. C, D, MembraneI–V relationships showing the occlusion of 1S,3R-ACPD effect by Ba²⁺. 1S,3R-ACPD produced an inward current and increased input resistance in the absence of Ba²⁺ (C). In the presence of Ba²⁺, the magnitude of inward current and the degree of the increase in input resistance by 1S,3R-ACPD was greatly attenuated (D). E, I–V plots for Ba²⁺-sensitive and Ba²⁺-resistant components of 1S,3R-ACPD-induced current. The I–V plot of Ba²⁺-sensitive component was obtained by subtracting I_acpd in the absence of Ba²⁺ from that in the presence of Ba²⁺. The identical protocols, as described in Figure 5, were used to generate the I–V plot of Ba²⁺-resistant component. Voltage step size, 5 mV; pulse width, 100 msec; pulse frequency, 2 Hz.