Figure 1

Cx43 affects TRPV1-mediated Ca ²⁺ influx in adipocytes. A. TRPV1 and Cx43 were detected in mesenteric adipose tissue (Vis) and 3T3-L1 preadipocytes (3T3-L1). M indicates the marker. B and C. Immunofluorescence demonstrated specific staining for co-expressed TRPV1 and Cx43 in the cell-cell connecting portions in primary cultured human visceral adipocytes B and visceral adipose tissues from both wild-type mice (WT) and humans C. The green fluorescence indicates Cx43. The red fluorescence indicates TRPV1. Nuclei in all groups were stained in blue with DAPI. The images were collected using a Nikon TE2000-U inverted fluorescence microscope and are representative of 3 separate experiments. The scale bar indicates 25 μm. D. Representative curves (left panel) show [Ca²⁺] _i changes in 3T3-L1 preadipocytes acutely stimulated with capsaicin (Cap, 1 μmol/L), capsaicin with the TRPV1 antagonist capsazepine (Cap + Capz, 1 μmol/L), the Cx43 inhibitor, 18α-glycyrrhetinic acid (Cap + 18α-GA, 100 or 150 μmol/L), or the intracellular Ca²⁺ chelator, BAPTA-AM (10 μmol/L). The summary data (right panel) show the maximal stimulated changes of [Ca²⁺] _i (25-150 s) from the baseline (0-25 s). Values were expressed as the mean ± SEM; n = 4 per group. **P < 0.01 vs. Cap; ^##P < 0.01 vs. Cap + Capz; ^ΔP < 0.05, ^ΔΔP < 0.01 vs. Cap + 18α-GA 100 μM.