DAYTIME WAKING AUTONOMIC FUNCTION AND VASCULAR CONTROL IN OSA

This paper deals with the potential role of two blood pressure regulat ory systems in the development of hypertension in obstructive deep apn oea (OSA). Beside the acute and long-term sympathoexcitation documente d in this disease, there seems to be an impaired endothelium-dependent vascular relaxation. In particular, nitric oxide (NO)-mediated vasodi latation was impaired in patients with OSA. Both these changes act to increase blood pressure during physiological conditions. However, they may not be determinants for hypertension development in OSA as no dif ferences between normo- and hypertensive patients with OSA were detect ed, Nevertheless, an altered balance between the vasoconstrictive infl uence of the sympathoadrenergic system and the vasodilatory action of NO-dependent vascular relaxation may be of importance in the developme nt of sustained hypertension in OSA.