Figure 4. α₁AR signaling augments Po of L-type Ca²⁺ channels (LTCCs) in hippocampal neurons.

(A, E) Seals were formed by the recording pipettes before application of phenylephrine (PHE) or norepinephrine (NE) and ultimately of either isradipine or nimodipine to ensure channel activity was mediated by LTCCs. (B) Sample diary shows time course of Po before and after application of 10 µM PHE and then 10 µM isradipine. The number of channels under the patch was estimated based on the maximal number of observed stagged openings in each patch (k; upper left). (C) Ten consecutive traces from representative cell-attached single-channel LTTC recordings before and after application of PHE and then isradipine. Bottom panels show ensemble averages. (D) PHE increases Po (left) and peak currents of ensemble averages (n = 12 cells; right). (F) Sample diary shows time course of Po before and after application of 10 µM NE and then 10 µM isradipine. (G) Ten consecutive traces from representative cell-attached single-channel recordings of LTCCs before and after application of NE and then nimodipine. Bottom panels show ensemble averages. (H) NE increases Po (left) and peak currents of ensemble averages (n = 8 cells; right). (D, H) Data are presented as means ± standard error of the mean (SEM). Statistical significance was tested by a paired, two-tailed Student’s t-test, *p ≤ 0.05. Panels A and E were created using Biorender.com.