Figure 6.

Single-channel recordings in outside-out patches taken from cultured hippocampal neurons. (A) An example record showing the activation of single-channel openings in response to a step reduction in the concentration (2 to 0 mM) of Ca²⁺. The holding potential was −60 mV. (B) I-V relationship for single-channel currents. Representative trances show the activation of these currents at holding potentials ranging from −60 to 0 mV. The I-V curve was constructed from the results of recordings from eight such patches. The channel showed a linear I-V relationship with a slope conductance of 36 ± 2.6 pS (n = 8). (C) Effect of Gd³⁺ on single-channel currents. Gd³⁺ (0.002 mM) significantly decreased the channel-open probability (control P_o = 0.21 ± 0.13; Gd³⁺ P_o = 0.10 ± 0.07, n = 5, P < 0.05) without having any effect on single-channel amplitude.