Crotty T P
Anatomy Department, University College, Cork, Ireland.
Med Hypotheses. 1991 Jan;34(1):41-8. doi: 10.1016/0306-9877(91)90063-5.
Noradrenaline can dilate a canine lateral saphenous vein which at the time is constricted by noradrenaline. It does so when it is released from the vasa vasorum network of the constricted vein. By filling a limited section of the network of a normal, tonically constricted vein with endogenous noradrenaline it is possible to dilate the vein locally, in effect creating an acute experimental varicosity. These findings have led to the proposal that human varicosities are an active response of the vein to endogenous noradrenaline released from sections of its vasa vasorum network. The noradrenaline involved is part of the circulating overflow derived from normal adrenergic nerve activity. A bout of turbulence in the vein lumen is proposed as the trigger which causes a reflux of hypoxic blood and the endogenous noradrenaline in it from the vein lumen to the vasa. The size and shape of the varix reflects the mosaic pattern of a vein's vasa vasorum network. The site of the varicosity is determined by the location in the vein lumen of the bout of turbulent non-laminar flow.
去甲肾上腺素能使处于被去甲肾上腺素收缩状态的犬隐外侧静脉扩张。当它从收缩静脉的血管滋养管网释放时就能做到这一点。通过用内源性去甲肾上腺素填充正常的、呈紧张性收缩静脉的有限部分管网，有可能使静脉局部扩张，实际上形成急性实验性静脉曲张。这些发现导致了这样一种观点，即人类的静脉曲张是静脉对从其血管滋养管网部分释放的内源性去甲肾上腺素的一种主动反应。所涉及的去甲肾上腺素是正常肾上腺素能神经活动产生的循环溢流的一部分。静脉腔内的一阵湍流被认为是引发因素，它会导致缺氧血液及其所含的内源性去甲肾上腺素从静脉腔反流至血管滋养管。静脉曲张的大小和形状反映了静脉血管滋养管网的镶嵌模式。静脉曲张的部位由湍流的非层流在静脉腔内的位置决定。
