Fig. 5.

The tonic GABA receptor current is reduced by voltage-gated Ca²⁺ channel inhibitors. A: example traces showing the effect of the voltage-gated Na⁺ channel inhibitor tetrodotoxin (TTX) and the voltage-gated Ca²⁺ channel inhibitors CdCl₂ and nifedipine on the tonic current in KCs. CdCl₂ (200 μM) had no effect on I_m following inhibition of the tonic GABA current with PTX. B: pooled data for the effect of TTX (n = 3), CdCl₂ (Cd²⁺; n = 3), and nifedipine (Nifed.; n = 3) on the tonic GABA current. The effects were quantified as the percentage inhibition of the PTX-sensitive component of I_m. *P < 0.05, statistical significance.