[The effect of renal dopamtne receptor blockade on natriuresis induced by volume expansion and intracerebroventricular injection of hypertonic saline in rabbits].

The present study was carried out to study the effects of renal dopamine receptor blockade on natriuresis induced by volume expansion (VE) and intracerebroventricular injection of hypertonic saline (ICHNa) in connexion with the use of dopamine receptor blockers haloperidol (Hal) in anesthetized rabbits. In the VE experiments, Hal group decreases the peak increase of UNa V from control group of 65.0 +/- 15.0 to 19.0 +/- 5.5 mumol/min (P < 0.02). In the ICHNa experiments, the peak increase of UNa V in control and Hal groups were respectively 28.9 +/- 4.6 and 29.0 +/- 5.8 mumol/min (P > 0.50). In the experiments of rabbit with intact renal dopamine receptor, the natriuresis induced by VE+ICHNa was significantly greater than those due to either inducing factor acting alone. Renal dopamine receptor blockade also significantly attenuated the natriuresis induced by VE+ICHNa. These results indicate that renal dopamine receptor blockade significantly attenuated the natriuresis induced by VE or VE+ICHNa, but did not affect the response of ICHNa. In the rabbits with intact renal dopamine receptor, the natriuretic response induced by VE+ICHNa was significantly greater than those response by either inducing factor acting alone.