INTERACTION AMONG ATRIAL-NATRIURETIC-FACTOR (ANF), VASOPRESSIN, AND RENAL NERVES IN TERMS OF RENAL RESPONSES IN RATS

The relationship between the renal nerves and vasopressin in terms of the natriuretic and diuretic responses to atrial natriuretic factor (ANF - 0.25 ug/kg/min for 15 min), was investigated in unilaterally denervated anesthetized rats before and after the administration of a vasopressin V2 specific antagonist (AVPX) - (40 ug/kg bolus followed by 0.4 ug/kg/min infusion). Administration of the AVPX or ANF did not alter the arterial pressure. Acute renal denervation or AVPX administration independently produced significant increases in sodium and water excretion. ANF infusion by itself produced a greater increase in urine flow and sodium excretion from the denervated kidney compared to the intact kidney before the administration of AVPX. However, after the administration of AVPX renal responses to ANF from the intact kidneys were enhanced such that they were not significantly different from the denervated kidneys. These results suggest that the full physiological response to ANF may be masked by tonic renal nerve activity or antidiuretic actions of vasopressin. Furthermore, since combined renal denervation and AVPX administration does not produce any greater potentiation of the renal responses to ANF than either of these manipulations alone, it is suggested that they may act via a common mechanism, possibly altering activity in the renal nerves. © 1991.