THE EFFECTS OF DOPAMINE ON KIDNEY-FUNCTION OF RATS

  • 1 January 1981
    • journal article
    • research article
    • Vol. 252  (2) , 219-228
Abstract
The dose-response effects of dopamine on kidney function were studied in rats. The arterial blood pressure was increased only transiently, after continuous i.v. infusion of dopamine for 2 h, while heart rate was elevated throughout. Drastic diuresis was usually observed during the early phase of infusion especially when the dose of dopamine was greater than 46 .mu.g/min-kg body wt [BW]. Natriuresis was also dose-dependent but its duration was much more prolonged than diuresis. Both the increase in glomerular filtration rate (GFR) and reduction in tubular salt reabsorption may be responsible for this elevation in the rate of Na excretion. Dopamine, at low dose, insignificantly increased the GFR but, at a higher dose (90 .mu.g/min-kg BW), a 16% increment was observed. This elevation in GFR may not be due to a concomitant increase in the renal blood flow, since phenoxybenzamine, an .alpha.-adrenergic blocking agent which would further reduce the renal vascular resistance, abolished the effects of dopamine on GFR, diuresis and natriuresis. The increase in GFR may be due to the differences in the responsiveness of the afferent and the efferent arterioles to dopamine in the presence of normal .alpha.-adrenergic receptors. Dopaminergic receptors in the kidney of rat, if present, may not play a significant role in determining the renal function.

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