Precapillary arteriole

Precapillary arterioles are the final small-diameter branches of the arterial system that deliver blood directly to the capillary beds (StatPearls, 2023). These vessels are primarily composed of endothelial cells and a layer of smooth muscle, which allows them to act as the principal site of peripheral resistance in the cardiovascular system (NIH, 2022). By adjusting their diameter through contraction or relaxation, they regulate both local tissue perfusion and systemic blood pressure. Although they are anatomical structures rather than individual molecules, they house various receptors and channels—such as alpha-1 adrenergic receptors and voltage-gated calcium channels—that serve as primary targets for antihypertensive and vasodilator drugs (PubMed, 2021). Dysfunction of precapillary arterioles is central to the pathogenesis of essential hypertension and microvascular complications in diabetes. They are also involved in the autoregulation of blood flow in vital organs like the brain and kidneys. Therapeutic intervention at this level often aims to reduce the workload on the heart by decreasing afterload through vasodilation.

Other names

Terminal arterioleResistance vesselMetarteriole

Modulation of vascular smooth muscle tone through various molecular pathways, including calcium channel inhibition, alpha-adrenergic antagonism, and nitric oxide-mediated vasodilation.