Figure 1.

The kidney plays a key role in the regulation of cardiovascular function and in pressure homeostasis. Two main functions of the kidney are involved in cardiovascular control: the production and release of renin with consequent production of angiotensin II, a powerful vasoconstrictor agent, and the urinary excretion of Na which affects the fluid balance. Both of these effects are influenced by adrenergic nerve factors that play a key role in controlling renin release and saline balance through both direct and indirect mechanisms. In particular, the sympathetic nervous system has a key role in the regulation of perfusion and renal function through afferent and efferent fibres that reach the kidneys from the aorta with fibres located in the adventitia of the renal arteries.