Renal alpha adrenoceptors.

The alpha adrenoceptors modulate renal blood flow, electrolyte balance, and metabolism. In most species both alpha 1 and alpha 2 subtypes are present. The alpha 1 adrenoceptors control blood flow and increase sodium reabsorption and gluconeogenesis. Radioligand studies indicate that the majority of alpha 1 adrenoceptors are located on proximal tubules. The alpha 2 adrenoceptors inhibit adenylate cyclase, and their density varies among species as do the molecular characteristics. In rat but not guinea pig some alpha 2 adrenoceptors are associated with glomeruli, but in both species most receptors are found on proximal tubules.