Acetylcholine releases endothelium-derived hyperpolarizing factor and EDRF from rat blood vessels.

摘要: Abstract 1. The effects of haemoglobin and methylene blue on the acetylcholine (ACh)-induced electrical mechanical responses smooth muscle cells were investigated in rat aorta main pulmonary artery. 2. When endothelium was intact, ACh induced a transient hyperpolarization sustained relaxation tissues precontracted with noradrenaline. Both absent preparations without endothelium. 3. Haemoglobin inhibited ACh-induced relaxation, but not hyperpolarization. 4. In an intact endothelium, produced increase both rate 86Rb efflux tissue cyclic GMP levels. changes ion flux unaffected by either or concentrations which almost abolished concentrations. 5. arteries indomethacin had no effect 6. It is concluded that artery, releases two different substances, endothelium-derived relaxing factor (EDRF) hyperpolarizing (EDHF), from endothelial cells. Neither substance appears to be derived pathway dependent cyclo-oxygenase. EDHF seems play minor role noradrenaline-induced contractions.