Fig. 8.

The standard HFS trains evoke large GABAergic bicarbonate-dependent [K⁺]_o transients in the CA1 region at the standard distance from the site of stimulation. A, The stimulation-induced [K⁺]_o transient is affected only slightly by the presence of ionotropic glutamate receptor agonists. (The left trace is the only recording shown in the present study that was obtained in the absence of ionotropic glutamate antagonists.) B, The stimulation-induced [K⁺]_o is suppressed in the absence of CO₂/HCO₃⁻.