Sildenafil increases sympathetically mediated vascular tone in humans.

Background: Sildenafil, a selective phosphodiesterase-type-5 (PDE-5) inhibitor, produces vasodilation that improves erectile dysfunction and pulmonary hypertension. Sildenafil could also cause baroreflex sympathetic activation that would enhance vascular tone and oppose direct vasodilation. We tested the hypothesis that sildenafil administration increases sympathetically mediated vascular tone in healthy middle-aged men.

Dissociation between sympathetic nerve traffic and sympathetically mediated vascular tone in normotensive human obesity.

Obesity increases the risk of hypertension and its cardiovascular complications. This has been partly attributed to increased sympathetic nerve activity, as assessed by microneurography and catecholamine assays. However, increased vasoconstriction in response to obesity-induced sympathoactivation has not been unequivocally demonstrated in obese subjects without hypertension.

Impaired skeletal muscle and skin microcirculatory function in human obesity.

Background: Obesity is associated with exaggerated blood pressure and systemic vascular resistance responses to mental stress.

Objective: To test the hypothesis that skin and muscle microvascular dilatation in response to mental stress is blunted in obesity.

Design And Methods: Blood pressure, heart rate and forearm and skin blood flow responses to mental stress were compared in 23 obese and 23 age- and sex-matched lean normotensive individuals.

Role of endothelin in cardiovascular disease.

Endothelins are a family of peptides, which comprises endothelin-1 (ET-1), endothelin-2 (ET-2) and endothelin-3 (ET-3), each containing 21 amino-acids. ET-1 is a peptide secreted mostly by vascular endothelial cells, the predominant isoform expressed in vasculature and the most potent vasoconstrictor currently known. ET-1 also has inotropic, chemotactic and mitogenic properties.