Pressure-induced myogenic responses in human isolated cerebral resistance arteries

Background and Purpose Pressure-induced myogenic responses have been demonstrated in cerebral resistance arteries isolated from a number of species. In the present study, we determined the response of human isolated cerebral resistance arteries to a pressure stimulus. Methods Arteries were set up in a pressure myograph and exposed to alterations in intravascular pressure. Results Human isolated cerebral resistance arteries developed spontaneous intrinsic tone in response to a pressure stimulus over the pressure range of 20 to 90 mm Hg that was not apparent in the absence of extracellular calcium. This intrinsic tone may be an inherent property of the vascular smooth muscle, since it remained after functional removal of the endothelium. Conclusions Human isolated cerebral resistance arteries spontaneously contract when exposed to raised intravascular pressure. This pressure-induced myogenic response may contribute to cerebral autoregulation of blood flow.