Role of endothelium-derived nitric oxide in mediating the natriuretic response to acute extracellular volume expansion
Fujioka, H.; Fujita, Y.; Syoji, T.; Uchida, K.; Takahashi, N.; Sumikura, T.; Yuasa, S.; Matsuo, H.
Nihon Jinzo Gakkai Shi 36(3): 201-208
1994
ISSN/ISBN: 0385-2385 PMID: 8196217 Document Number: 430087
To determine the role of endothelium-derived nitric oxide (EDNO) in mediating the natriuretic response to acute extracellular volume expansion (ECVE) with isotonic saline (3% of body weight per hour), the diuretic and natriuretic responses to ECVE were studied in anesthetized Sprague-Dawley rats during the intravenous infusion of an EDNO synthesis inhibitor, NW-nitro-L-arginine methyl ester (L-NAME). Intravenous infusion of L-NAME at the dose of 5 micrograms/kg/min significantly inhibited the diuresis and natriuresis in response to ECVE by 58% and 67%, without altering arterial pressure, effective renal plasma flow, glomerular filtration rate and basal excretory function. This inhibitory effect of L-NAME on the diuretic and natriuretic responses to ECVE was attenuated by the infusion of the EDNO synthesis precursor, L-arginine (1mg/kg/min), but not by D-arginine. In addition, pretreatment with 0.3 mg/kg of the angiotensin II receptor antagonist, L-158,809, normalized the diuretic and natriuretic responses to ECVE in L-NAME-treated rats, suggesting an angiotensin-II-dependency of the reduced renal excretory response to ECVE during EDNO synthesis inhibition. Neither L-arginine nor L-158,809 alone significantly altered the renal excretory response to ECVE compared with vehicle-treated control rats. These results suggest that EDNO might play an important role in the regulation of sodium and water excretion during ECVE, and indicate a possible interaction between EDNO and angiotensin II on the renal excretory function.