Beraprost

contraction and vasodilation of isolated mesenteric arteries was assessed in response to KCl (80mM) and cumulative dose-response curves of phenylephrine (PE), acetylcholine (Ach, endothelium-dependent vasodilator), sodium nitroprusside (SNP, endothelium independent vasodilator) and beraprost (PGI₂ analogue, endothelium-derived vasodilator). Reagents were purchased from Sigma-Aldrich (PE, Ach and SNP) and Cayman (beraprost). Arterial segments (2mm long) were dissected and mounted on a wire-myograph (Danish MyoTechnology, DMT) as previously described [26 (link)]. Briefly, 2 tungsten wires (25μm diameter) were inserted into the lumen of the artery and fixed respectively to a force transducer and a micrometer. Arteries were bathed in a 5ml organ bath containing a physiological salt solution (PSS) maintained at a pH of 7.4, a pO₂ of 160mmHg and a pCO₂ of 37mmHg. After wall tension normalization, arteries were allowed to stabilize for 30 minutes. Endothelial integrity was assessed after pre-constriction with 10^-6M PE by evaluating the vasodilator effect of 10⁻⁶ M Ach. Endothelium-independent relaxation to SNP was obtained at the end of the protocol. Cumulative concentration-response curve to Ach, SNP and beraprost were performed after PE-induced pre-constriction (10^-6M). Data were expressed as a % relaxation of PE-induced pre-contraction.