ObjectivesCarbon dioxide (CO2) is known to affect thermal sensation and vasodilatation in human skin immersed in CO2‐rich water. However, the role that CO2 plays in these mechanisms is unclear. Transient receptor potential vanilloid 1 (TRPV1) is a member of a non‐selective cationic channel family expressed in human sensory neurons. Activation of TRPV1 is induced by heat and chemical agonists such as H+. This study aimed to clarify the role of CO2 in regulating TRPV1 expression in vascular smooth muscle cells.MethodsA7r5 rat smooth muscle cells were maintained in Dulbecco’s modified Eagle’s medium supplemented with 10% fetal bovine serum at 37°C in a 5% CO2 incubator. The cells were exposed to 20% CO2 for 24 hours. The expression of TRPV1 and TRPV4 were subsequently evaluated by real time PCR.ResultsThe expression levels of TRPV1, but not TRPV4, were significantly increased ( P =0.013) in the vascular smooth muscle cells following exposure to 20% CO2 for 24 hours.ConclusionsThese results suggest that exposure to CO2 may regulate the expression of TRP family proteins in cultured vascular smooth muscle cells.Support or Funding Informationnone