[Effect of catecholamines on sodium resorption and oxygen tension in rat kidneys]

Functional significance of alpha- and beta-adrenoreceptors for the mechanism of catecholamines effect on sodium reabsorption and oxygen tension in the rat kidney, was studied. Adrenaline inhibited sodium excretion decreasing its filtration in glomeruli and stimulating its reabsorption in tubules. The oxygen tension in these conditions did not change in the renal cortex while oxygenation of the external cortical layer was significantly increased. The blocking agent for alpha-adrenoreceptors phentolamin abolished the inhibiting effect of adrenaline on the glomerular filtration and somewhat decreased the degree of oxygen tension growth in the external cortical layer, leaving the tubular effect unaltered. The blocking agent for beta-adrenoreceptors inderal did not affect the inhibitory action of adrenaline on the glomerular filtration but completely prevented its activating effect on the tubular reabsorption of sodium and on oxygenation of the external cortical layer. A conclusion was drawn that catecholamines stimulation of sodium reabsorption in the rat kidney follows excitation of beta-adrenoreceptors. The increase in oxygen tension in the external cortical layer under effect of catecholamines is supposed to improve energetic supply of the sodium active transport in the ascending portion of the Henle loops.