The sympathetic nervous system and renal sodium handling: is dopamine involved?

The presence of vascular dopamine receptors and dopaminergic nervous fibers in the kidney suggests that dopamine plays a role in the control of renal function by the autonomic nervous system. Dopamine and norepinephrine have contrary effects in the kidney. This is particularly apparent at the level of efferent glomerular arterioles. Variations in postglomerular vascular resistance may induce variations in the filtration fraction and in peritubular oncotic pressure, thus influencing proximal tubule sodium reabsorption. We propose that the sympathetic innervation of the kidney controls the postglomerular vascular resistance; this control can be achieved through a balance between the vascular effects of dopamine and norepinephrine.