An alpha-adrenotypic study of the isolated rabbit kidney at normo- and hypothermia

Rabbit kidneys were isolated and perfused at 37degrees and 25degrees C with a balanced salt solution and the effects of an alpha agonist and antagonist were tested in several parameters. Perfusion pressure, resistance, perfusate and urine flow, creatinine and PAH clearance, and Na+ and K+ transport were among the parameters studied. At 25degrees C the vascular responses to norepinephrine (NOR) were potentiated in relation to 37 degrees C. Blockade of the reuptake by cocaine and depletion of catecholamines by reserpine was observed to promote a small potentiation of NOR effects on renal vessels as measured by perfusion pressure. This pharmacological treatment compromised kidney function especially after the first 40 min of perfusion, that is to say that after NOR infusion functional parameters were extremely low. During the infusion of NOR there was a decrease in GFR, urinary flow and CPAH, which was even more intense at 25 degrees C. It was concluded that alpha adrenergic receptors are more responsive at 25 degrees C than at 37 degrees C in kidney vascular receptors. There was no difference in regard to alpha blockade at either temperature tested.