Figure 7. Actions of I_bacl on GEPs.

I_bacl lowers the peak levels achieved by glutamate-evoked potentials (GEPs). A, schematic shows the recording configuration. l-Glutamate (1 mm) or AMPA (0.1–1 mm) was repeatedly pressure-applied (duration 3–8 ms; interstimulus interval, 20 s) to the middle of the dendritic arbor of a cultured Purkinje cell through a pipette. The agonist-evoked potentials were recorded from the soma using a perforated-patch current-clamp technique. The saline contained 3 mm KCl, 0.3–0.5 μm TTX, and 10 μm bicuculline but not kynureic acid. B and C, sample GEPs recorded from single cells consecutively before (Basal), during (80–180 s of baclofen onset, Baclofen) and after (Wash) baclofen application (3 μm) in the BaCl₂-free (B) or 1 mm BaCl₂-containing (C) saline. Baclofen was bath-applied. Each trace indicates the average of three to six records. D, mean change in the peak level achieved by GEPs from the basal to baclofen records in the BaCl₂-free (n = 6, −) and 1 mm BaCl₂-containing (n = 5, +) saline. Hyperpolarizing shift is taken as positive. Error bars, ± s.e.m.*P < 0.05; n.s., P > 0.05; between the basal and baclofen records, respectively, Student's paired t test. E, sample AMPA-evoked potentials (AEPs) recorded from a cell consecutively before (Basal), during (80–180 s of baclofen onset, Baclofen) and after (Wash) baclofen application (3 μm) in the BaCl₂-free saline. Each trace indicates the average of six records.