[Autonomic nervous system in arterial hypertension]

In several experimental animal models of hypertension, alterations in the autonomic cardiovascular drive have been shown to participate in the development and/or in the maintenance of high blood pressure. This has been shown to be true also in case of hypertension occurring in humans in whom a reduction in the parasympathetic influences to the heart is paralleled by an increase in the cardiac and vascular adrenergic tone. Several factors have been claimed to favor the hyperadrenergic state of essential hypertension. These include 1) a dysfunction in the central mechanisms physiologically inhibiting adrenergic outflow, 2) a sympathoexcitation induced by humoral factors (hyperinsulinemia, activation of the renin-angiotensin system, etc.), and 3) a functional alteration in arterial baroreceptors and in cardiopulmonary receptors which restrains in normal conditions adrenergic activity. Evidence has been provided indicating that the autonomic derangement occurring in hypertension contributes to the development of the target organ damage associated with the hypertensive state. This represents the rationale for employing, in the treatment of high blood pressure states, drugs exerting sympathoinhibitory effects.