Catecholamines increase urine formation in isolated toad (Bufo marinus) kidneys perfused at constant rate.
Infusion of catecholamines into isolated kidneys of the toad (Bufo marinus) perfused at constant rate, produced increased arterial pressure accompanied by increased glomerular filtration rate, urine formation rate and sodium excretion. These parameters were all increased by arterial infusion of adrenaline or noradrenaline, or by infusion of adrenaline via the renal portal veins. Portal venous pressure increased slightly after arterial or portal infusion of adrenaline, but decreased after arterial infusion of noradrenaline. Estimation of segmental pressure gradients indicated that the efferent glomerular arterioles were selectively constricted by low concentrations of adrenaline or noradrenaline (3 X 10(-9), 3 X 10(-8) mol l(-1)). Higher concentrations of these amines constricted the preglomerular, as well as the postglomerular vasculature. These results demonstrate that the pericytes and/or endothelial cells which form the walls of the efferent arterioles in B. marinus are capable of active contraction.
D000818:Animals; D002024:Bufo marinus; D002395:Catecholamines / Q000494:pharmacology*; D004231:Diuresis / Q000187:drug effects*; D004837:Epinephrine / Q000494:pharmacology; D005919:Glomerular Filtration Rate / Q000187:drug effects; D066298:In Vitro Techniques; D007668:Kidney / Q000187:drug effects* / Q000502:physiology; D007678:Kidney Glomerulus / Q000187:drug effects; D007684:Kidney Tubules / Q000187:drug effects; D008297:Male; D009318:Natriuresis / Q000187:drug effects; D009638:Norepinephrine / Q000494:pharmacology; D010477:Perfusion; D014655:Vascular Resistance / Q000187:drug effects
D002395:Catecholamines; D009638:Norepinephrine; D004837:Epinephrine