Fig. 2: Voltage-dependent currents and exocytosis in human α-cells.
From: Paracrine control of α-cell glucagon exocytosis is compromised in human type-2 diabetes
a Families of voltage-clamp current responses in human ND and T2D α-cells. Currents were elicited by 50 ms depolarizing pulses (−70 to +80 mV in 10 mV increments) from a holding potential of −70 mV. For clarity, only the responses between −40 mV and +10 are shown. b, c Current (I)–voltage (V) relationships for Ca2+ (B, average current during 5–45 ms of the depolarization in a) and Na+ (c, peak current during the first 5 ms of the depolarization in a) currents recorded from ND (n = 38, 4 donors, black) and diabetic T2D (n = 32, 3 donors, red) cells as in a. Currents are normalized to cell size (pF). Data are presented as mean values ± SEM. d Cell capacitance increase (ΔCm) during a train of 14 × 200-ms depolarizations from −70 mV to 0 mV in ND (black) and T2D (red) α-cells. e Average change in membrane capacitance, normalized to initial cell capacitance (ΔC/C0), during the 1st depolarization (#1), and total increase during the train (Σ1-14) for ND (n = 20, 4 donors, black) and T2D (n = 18, 3 donors, red) α-cells. Data are presented as mean values ± SEM. f Whole-cell membrane capacitance (CM) in T2D (n = 48, 7 donors) and ND (n = 66, black, 8 donors) α-cells. Dots represent individual cells, and lines are mean values. Each donor is represented by a single color.
