TRPV₁ channels in human skeletal muscle feed arteries: implications for vascular function

Area of Science:

• Cardiovascular Science
• Vascular Physiology
• Ion Channel Research

Background:

• Skeletal muscle feed arteries (SMFAs) are crucial for regulating blood flow during exercise.
• The role of transient receptor potential vanilloid type 1 (TRPV1) channels in SMFA vascular function is not well understood.

Purpose of the Study:

• To determine if human SMFAs express functional TRPV1 channels.
• To investigate the role of TRPV1 channels in modulating vascular responses in SMFAs.

Main Methods:

• Wire myography was used to study SMFAs from 16 human donors.
• TRPV1 channel activation was assessed using capsaicin, a TRPV1 agonist.
• Vascular responses to phenylephrine, dexmedetomidine, acetylcholine (ACh), and sodium nitroprusside were measured with and without capsaicin.

Main Results:

• Capsaicin significantly attenuated phenylephrine- and dexmedetomidine-induced vasocontraction.
• Capsaicin robustly enhanced ACh-induced vasorelaxation in an endothelium-dependent manner.
• TRPV1 channels are predominantly located in the endothelium of SMFAs.

Conclusions:

• Human SMFAs express functional TRPV1 channels that modulate vascular function.
• TRPV1 channel activation opposes alpha-adrenergic receptor-mediated vasoconstriction and enhances vasodilation.
• TRPV1 channels represent a potential therapeutic target for improving vascular function and may contribute to functional sympatholysis during exercise.