Influence of infusion of deoxycorticosterone acetate on the responses of kidney function elicited by stimulation of the peripheral arterial chemoreceptors with almitrine bismesylate in anaesthetized rats.

In two groups of male, normotensive, spontaneously breathing rats in chloralose-urethane anaesthesia the peripheral arterial chemoreceptors were stimulated by intravenous infusion of almitrine bismesylate (0.25 mg/kg). The experiments were carried out in moderate osmotic diuresis. In one series desoxycorticosterone acetate (DOCA) was infused at a rate of 35-40 ng/min.100 g body weight. Urine was collected via a bladder catheter. Kidney hemodynamics as well as tubular and excretory function were determined using the clearance-technique. In both groups of animals administration of almitrine caused an increase of breathing rate as well as an increase of the oxygen tensions and the pH-values in the arterial blood. Mean systemic arterial blood pressure, effective renal plasma flow and glomerular filtration rate decreased slowly with the time of the experiments, whereas renal hemodynamic resistance tended to increase both in the control and in the DOCA treated group. In both groups of animals intravenous infusion of almitrine was followed by an inhibition of renal tubular sodium reabsorption and an increase of both the absolute and the fractional salt excretion. The data indicate that arterial chemoreceptor stimulation in rats causes an inhibition of renal tubular sodium reabsorption which does not result from a reduced tubular action of mineralocorticoid hormones.