Endothelial coordination of cerebral vasomotion via myoendothelial gap junctions containing connexins 37 and 40

bral vasculature differs from that of systemic vessels outside the blood-brain barrier. The hypothesis that the endothelium modulates vasomotion via direct myoendothelial coupling was investigated in a small vessel of the cerebral circulation. In the primary branch of the rat basilar artery, membrane potential, diameter, and calcium dynam-ics associated with vasomotion were examined using selective inhib-itors of endothelial function in intact and endothelium-denuded arter-ies. Vessel anatomy, protein, and mRNA expression were studied using conventional electron microscopy high-resolution ultrastruc-tural and confocal immunohistochemistry and quantitative PCR. Membrane potential oscillations were present in both endothelial cells and smooth muscle cells (SMCs), and these preceded rhythmical contractions during which adjacent SMC intracellular calcium con-centration ([Ca2]i) waves were synchronized. Endothelium removal abolished vasomotion and desynchronized adjacent smooth muscl