Isolated resistance artery preparation.

The blood vessels that contribute most to precapillary resistance are known as resistance arteries, consisting of arterioles and small arteries with diameters of less than 500 μm (1). These vessels regulate the vascular resistance, and thus the blood supply, through the adjustment of their lumen diameter, which is accomplished by modulation of the level of tone in the vascular smooth muscle cells. The smooth muscle and endothelial cells in the blood vessel wall are sensitive to a great diversity of stimuli including distending pressure, shear stress, neurohumoral factors, and metabolites. All of these different signals are sensed, integrated, and eventually lead to a response.