| Abstract: | In the present study we examined the role of the afferent renal nerves in the control of ipsilateral renal adaptation to sodium restriction. Uninephrectomized rats were subjected to selective renal deafferentation or sham operation, instrumented with catheters and housed in metabolism cages to collect urine in 90 min fractions. Only sodium deficient food (0.03% Na+) was allowed. Water and sodium excretion were stabilized via a continuous 48 h infusion (1.25 ml h-1) of a Ringer's solution. During this period water, sodium and potassium excretion were similar in renal deafferented and sham operated rats. Then, the infusion was exchanged for a modified Ringer's solution, in which the sodium ion was replaced by the choline ion. Measurements were performed over 24 h. During the choline Cl infusion, urine flow increased similarly in renal deafferented and sham-operated rats. In both groups of rats, sodium excretion decreased within 24 h by more than 95 %, whereas potassium excretion stayed constant. Sodium loss was higher in renal deafferented rats only in the first 90 min period after the exchange of the infusions. These results indicate that afferent renal nerves are not necessary in ipsilateral renal adaptation during 24 h sodium restriction, but may play a modulatory role in correcting transient changes in ipsilateral renal excretory function. |
