Mulvany M J
Danish Biomembrane Research Centre, Aarhus University.
J Hypertens Suppl. 1990 Dec;8(7):S225-32.
Both direct in vitro evidence and histological evidence strongly suggest that in essential hypertensive patients there is an alteration in the structure of proximal resistance vessels (small arteries); the media: lumen ratio is increased and the lumen volume is decreased. Although it may be supposed that essential hypertension is related to an increased sensitivity in the resistance vasculature, there is little evidence for this view, either from haemodynamic investigations, or from in vitro experiments. What evidence there is appears to be based primarily on results from the spontaneously hypertensive rat (SHR), but even here small artery sensitivity does not seem to be related to blood pressure. However, two functional abnormalities of the small arteries may be associated with hypertension. First, in small arteries from both essential hypertensive patients and SHR, cocaine has a greater ability to increase the noradrenaline sensitivity than in normotensive subjects, possibly due to increased innervation. Second, genetic experiments with SHR show that the oscillatory activity of small arteries (rhythmic changes in tone in response to agonist activation) is correlated with blood pressure. The role of these structural and functional abnormalities in the pathogenesis of hypertension is not clear. In particular, although the structural changes could account for the increased peripheral resistance, evidence that they are a primary cause of hypertension is lacking. However, the structural changes could play an important role in the morbid consequences of hypertension. Failure to normalize vascular structure with antihypertensive treatment could be one reason why treatment does not improve the prognosis as much as expected.
直接的体外证据和组织学证据均有力地表明，原发性高血压患者的近端阻力血管（小动脉）结构存在改变；中膜与管腔比值增加，管腔容积减小。尽管可以推测原发性高血压与阻力血管系统敏感性增加有关，但无论是血流动力学研究还是体外实验，都几乎没有证据支持这一观点。现有的证据似乎主要基于自发性高血压大鼠（SHR）的实验结果，但即便如此，小动脉敏感性似乎也与血压无关。然而，小动脉的两种功能异常可能与高血压有关。其一，在原发性高血压患者和SHR的小动脉中，可卡因增强去甲肾上腺素敏感性的能力比正常血压者更强，这可能是由于神经支配增加所致。其二，对SHR进行的遗传学实验表明，小动脉的振荡活动（对激动剂激活产生的节律性张力变化）与血压相关。这些结构和功能异常在高血压发病机制中的作用尚不清楚。特别是，尽管结构改变可以解释外周阻力增加，但缺乏证据表明它们是高血压的主要病因。然而，结构改变可能在高血压的不良后果中起重要作用。抗高血压治疗未能使血管结构恢复正常，可能是治疗未能如预期那样改善预后的一个原因。
