[The role and clinical importance of nitric oxide-endothelin system in hypertension]

This review summarises the role of the endothelium in the regulation of the vascular tone, emphasizes the importance of nitric oxide and endothelin at the vasodilator and vasoconstrictor physiological processes. Mainly, the nitric oxide is responsible for the basal tone of the vasculature, but plenty of modifying factors (endothelin, angiotensin-II, prostacyclin) have also important effects. Endothelial dysfunction observable in hypertension, which characterised by disorder of the endothelium-dependent relaxation, and predominance of the vasoconstrictor processes. Disorder of synthesis, decreased biological activity and increased degradation of the nitric oxide could play a role in the fall of the basal vasodilator tone, as well as other factors influencing the production of nitric oxide. Due to a relaxation disorder, the vasoconstrictor endothelin come to the front, following morphological changes of the vessels, afterwards. Endothelial dysfunction of the medium size arteries lead to thickening of the intima, what can follow by non-invasive measurements at the common carotid arteries. It is unambiguous in hypertensive patients that augmenting the tone of the resistance vessels, the peripheral vascular tone increases. It is proved in hypertensive adults that damaged function of the cerebral arterioles results in decrease of the vasoreactivity following a hypo- or hypercapnic stimuli. The imbalance of the nitric oxide-endothelin system is not only a process what helps to partly explain the pathophysiology of hypertension, but also a therapeutic aim preventing the process of atherosclerosis.