Control of vascular tone by endogenous endothelin-1 in human pial arteries

Abstract

Background and Purpose - Endothelin-1 (ET) has been shown to be involved in human pathological conditions, but its physiological function remains to be elucidated. The aim of this work was to assess whether endothelium- derived ET was involved in the overall responsiveness of freshly isolated human pial arteries. Methods - Samples of cerebral cortex, otherwise discarded, were obtained during tumor or epileptic lesion resections (n = 10 donors). Arterial segments were isolated and mounted on a microvessel myograph. Results - Inhibition of nitric oxide (NO) formation with N(ω)- nitro-L-arginine (L-NA, 100 μmol/L) increased basal tone by 7±1%E(max) (n=5). This increase in tone was fully abolished in the presence of BQ123 (1 μmol/L; ET(A) receptor antagonist, P