Figure 1.

Transient receptor potential melastatin subtype 8 (TRPM8) is a functional Ca²⁺ channel in the sarcoplasmic reticulum (SR) coupling Ca²⁺ release to mitochondria in vascular smooth muscle cells (VSMCs). A, TRPM8 immunoreactivity was detected by the monoclonal anti‐TRPM8 antibody (125 kDa) in homogenates (h) and SR fractions of VSMCs from wild‐type (WT) but not Trpm8^−/− mice. IP ₃R served as an SR marker, voltage‐dependent anion channel as a mitochondrial marker, and tubulin as a cytosolic marker. Menthol (300 μmol/L)‐induced Ca²⁺ concentration changes in cytosol (B) and mitochondria (C) in Ca²⁺‐free medium was blunted by depleting calcium store using thapsigargin (TG, 1 μmol/L) in cultured VSMCs from WT and Trpm8^−/− mice. After menthol (300 μmol/L) treatment, TG (1 μmol/L) induced Ca²⁺ concentration changes in cytosol (D) and mitochondria (E) in Ca²⁺‐free medium in cultured WT and Trpm8^−/− VSMCs. **P<0.01 vs WT. C indicates cytosol; Mito, mitochondrial fraction; N, nuclear fraction. Data are expressed as mean±SEM. n=3. Men indicates menthol.