Conducted Vasomotion in Isolated Arterioles: Evidence for Multiple Cellular Mechanisms

Abstract

Many vasoactive agents, when applied to a discrete region of an arteriole, induce responses that spread bidirectionally along the vessel for distances that exceed those that can be accounted for by simple diffusion (6, 8, 17, 18). In the microcirculation, responses to agonists such as acetylcholine and phenylephrine conduct over distances of 2 mm or more (17). Based on the evidence summarized in Table 1, we have initiated a series of experiments designed to explore the hypothesis that conduction is an intrinsic property of the vessel wall and that it is likely an electrotonic spread of membrane potential change through gap junctions. The process of conduction thus represents a form of communication within the arteriolar wall that requires both inter- and intracellular signalling and that is thought to promote homogeneous flow regulation (5, 18). However, neither the intracellular signalling pathways that initiate the conducted signal nor the cell types that propagate the response have been elucidated.