Prostaglandins Synthesis in Rat Mesenteric Bed: Effects Acetylcholine and Bradykinin

pp 233-239

Abstract

The capability of the rat mesenteric bed to produce and release prostanoids as well as the influence of the vascular endothelium and the vasodilators ace-tylcholine (ACh) and bradykinin (BK) on that production were studied. Prostanoids were mea-sured by high-pressure liquid chromatography (HPLC). The perfused mesenteric bed produced prostaglandin (PG) 6-ketoF1 a, thromboxane (TX) B2(stable metabolites of prostacyclin and TXA2, respectively), PGE2 and PGF2 a. Removal of the endothelium induced a 50% reduction in the release of prostacyclin and TXA2. In the intact vascular bed, 1pM BK increased the production of prostacyclin andPGE2, wereas 10 μM ACh increased prostacyclin production. In the deendothelialized vascular bed,BK increased prostacyclin release whereas ACh in-creased TX production. The inhibition of NO-syn-thase with 100 pM L-NAME inhibited the BK effects but did not modified the ACh effects on prostanoid release. It is concluded that the rat mesenteric vascular bed produces vasodilator and vasoconstrictor prostanoids from endothelial and non-endothelial sources; that ACh and BK stimulates prostanoid release with different patterns and by different mechanisms and that the BK effects, particularly in the absence of the vascular endothelium, could induce a predominance of vasodilator prostanoids.