Sympathetic nervous system and hypertension in diabetic patients

Although it has been demonstrated that the sympathetic nervous system parti cipates in the genesis of essential hypertension, it is still unclear wheth er this system can also account for the increased incidence of arterial hyp ertension in diabetic patients. However, there are some observations which make this hypothesis extremely likely. In fact, it has been demonstrated th at in diabetic normotensive patients the reflex control of the sympathetic discharge is normal but in hypertensive patients there are some derangement s of the autonomic nervous tone control which may contribute to increasing the incidence of arterial hypertension in patients with Type 2 diabetes mel litus, In particular, on the one hand, it has been reported that in hyperte nsive patients hyperinsulinemia is able to induce a reflex activation of th e sympathetic tone which is 3-fold higher than that observed in normotensiv e subjects. On the other hand, it has been demonstrated that this abnormal sympathetic response is particularly harmful in subjects prone to develop e ssential hypertension since they are characterized by vascular insulin resi stance, which plays a permissive role in the development of essential hyper tension. Vascular insulin resistance is a type of endothelial dysfunction w hich impairs the insulin modulation of the vascular effects of sympathetic nervous activation. (C) 2000, Editrice Kurtis.