Role of renal nerves in development of hypertension in DOCA-salt model in rats: a telemetric approach.
Centrally mediated hyperactivity of the autonomic nervous system contributes to DOCA hypertension; however, the targeted peripheral vascular bed(s) remain unclear. We propose that if renal sympathetic activity is a factor in the development of DOCA-salt hypertension, then renal denervation (RDNX) should attenuate the hypertensive response. In protocol 1, uninephrectomized RDNX (n = 9) and sham-denervated (n = 6) Sprague-Dawley rats were allowed free access to 0.9% NaCl solution and 0.1% NaCl diet. Mean arterial pressure (MAP) and heart rate were telemetrically recorded for 4 days before and 36 days after DOCA (100 mg/rat) implantation; sodium and water balances were recorded daily. Protocol 2 was similar except that saline intake in sham rats (n = 7) was matched to that observed in RDNX rats of protocol 1 for 30 days; for the last 10 days, the rats were allowed free access to saline. Before DOCA in protocol 1, MAP was lower (P < 0.05) in RDNX rats (99 +/- 1 mmHg) compared with sham rats (111 +/- 3 mmHg); however, heart rate and sodium and water balances were similar between groups. RDNX attenuated the MAP response to DOCA by approximately 50% (DeltaMAP = 22 +/- 3 mmHg, where Delta is change in MAP) when compared with sham rats (DeltaMAP = 38 +/- 6). RDNX rats consumed significantly less saline than sham rats, and cumulative sodium and water balances were reduced by 33% and 23%, respectively. In protocol 2, a similar pattern in MAP elevation was observed in RDNX and saline-restricted, sham-denervated rats even when saline restriction was removed. These results indicate that the renal sympathetic nerves are important in hypertension development but that other factors are also involved.
Jacob
Frédéric
F
Department of Physiology, Lillehei Heart Institute, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Clark
Leah A
LA
Guzman
Pilar Ariza
PA
Osborn
John W
JW
D000818:Animals; D001794:Blood Pressure; D001835:Body Weight; D003900:Desoxycorticosterone; D004195:Disease Models, Animal; D006339:Heart Rate; D006977:Hypertension, Renal / Q000139:chemically induced / Q000503:physiopathology*; D007668:Kidney / Q000098:blood supply / Q000294:innervation* / Q000503:physiopathology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012079:Renal Circulation / Q000502:physiology*; D012965:Sodium Chloride; D013562:Sympathectomy; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D013686:Telemetry; D014882:Water-Electrolyte Balance / Q000502:physiology
D003900:Desoxycorticosterone; D012965:Sodium Chloride