[Effect of catecholamines on electrolyte and water transport in the nephron of lower vertebrates]

Micropuncture technique and electron microprobe analysis have been used to investigate the role of noradrenalin in ion and water balance in the renal tubules of the lamprey Lampetra fluviatilis and newt Triturus vulgaris. Noradrenalin decreased Na, K, and Ca concentrations in the proximal lumen of the lamprey increasing the value of (TF/P)in from 1.1 +/- 0.1 to 1.3 +/- 0.1 (p less than 0.001). Regitin blocked these effects. Noradrenalin perfusion of the peritubular capillaries in newt kidney increased ion and water reabsorption in the proximal segment of the nephron and resulted in differential changes of ion transport in the distal tubule, increasing reabsorption of Na, Cl and K and inhibiting that of Ca and Mg. The rate of glomerular filtration in the nephron remained practically unaffected. The data obtained reveal direct effect of noradrenalin on the renal tubular function in lower vertebrates, this effect being realized presumably via alpha-adrenoreceptors.