Figure 3.

Effect of ionotropic receptor blockade on TTX-insensitive DRP

A, DRP at 50T. Inset, simultaneously recorded CDP and DRP at a faster sweep speed. Each set of recordings shows superimposed sweeps in medium containing 150 nm TTX (control) and after sequential addition of 40 μm bicuculline (Bic), 100 μm AP-5 (AP-5 + Bic) and 50 μm CNQX (CNQX + AP-5 + Bic). B, effect of sequential application of 100 μm AP-5 (AP-5) and 40 μm bicuculline (Bic + AP-5) on TTX-resistant DRP at 50T. C, Mg²⁺ sensitivity of TTX- and CNQX-resistant DRP at 50T. Ca, reduction of TTX-resistant DRP (control) by 25 μm CNQX (CNQX). Cb, recovery of TTX- and CNQX-resistant DRP by eliminating Mg²⁺ (0 Mg²⁺ + CNQX). Cc, 40 μm bicuculline (Bic + 0 Mg²⁺ + CNQX) blocks the early component of the CNQX-resistant DRP in the absence of Mg²⁺ while the remaining DRP is blocked by 100 μm AP-5 (AP-5 + Bic + 0 Mg²⁺ + CNQX). A, B and C are from different preparations. All recordings were obtained in the presence of 150 nm TTX.