Human brain capillary endothelium - 2-arachidonoglycerol (endocannabinoid) interacts with endothelin-1

In brain, the regulatory mechanism of the endothelial reactivity to nitric oxide and endothelin-l may involve Ca2+, cytoskeleton, and vasodilator-stimulated phosphoprotein changes mediated by the cGMP/cGMP kinase system.(1) Endothelium of human brain capillaries or microvessels is used to examine the interplay of endothelin-1 with the putative vasorelaxant 2-arachidonoyl glycerol, an endogenous cannabimimetic derivative of arachidonic acid. This study demonstrates that 2-arachidonoyl glycerol counteracts Ca2+ mobilization and cytoskeleton rearrangement induced by endothelin-1. This event is independent of nitric oxide, cyclooxygenase, and lipoxygenase and is mediated in part by cannabimimetic CB1 receptor, G protein, phosphoinositol signal transduction pathway, and Ca2+-activated K+ channels. The induced rearrangements of cellular cytoskeleton (actin or vimentin) are partly prevented by inhibition of protein kinase C or high levels of potassium chloride, The 2-arachidonoyl glycerol-induced phosphorylation of vasodilator-stimulated phosphoprotein is mediated by cAMP, These findings suggest that 2-arachidonoyl glycerol may contribute to the regulation of cerebral capillary and microvascular function.