Action of methylene blue and haemoglobin in rabbit aorta in relation to the surface of drug entry.

摘要: The effect of methylene blue and haemoglobin has been evaluated by using a procedure restricting drug entry to one surface rabbit aortic rings. In preparations precontracted with noradrenaline, produced, via the intima, an additional rapid endothelium-dependent contraction. While was without adventitia, produced slow endothelium-independent contraction that diminished but not abolished in reserpine-pretreated animals. This augmentation noradrenaline-induced adventitia rabbits observed also phenylephrine methoxamine. Methylene blue, when added rings incubated 3H-(−)-noradrenaline, interfered neuronal uptake this amine enhanced outflow 3H. conclusion, mechanism applied intima. Haemoglobin is devoid effects indirect sympathomimetic effects. experiments intact no restriction it found enhancement tyramine-induced response markedly less than for noradrenaline same level plateau finding indicates endothelium-derived relaxing factor more effective on smooth muscle cell layers vicinity intima those close adventitia.