Arterial baroreflex deficit induced organ damage in sinoaortic denervated rats

To verify the independent role of the arterial baroreceptor dysfunction inv olved in target-organ damage in hypertension, sinoaortic denervated (SAD) r ats were used as a model of arterial baroreflex (ABR) deficit. SAD, isolate d aortic-denervated (AD), and isolated sinus-denervated (SD) rats were inst rumented to record blood pressure (BP), heart rate (HR), BP variability (BP V), HR variability (HRV), ABR function control of heart period (ABR-HP), an d BP (ABR-BP). Vascular maximum contractile/relaxant function was determine d and organ damage was estimated by observation of morphologic changes. Sho rt-term (postoperative I week) SAD caused hypertension and tachycardia in r ats. Eighteen weeks after operation, BP and HR values in SAD and SD rats we re not different from those in sham-operated rats. but AD rats were hyperte nsive compared with control group. Although 24-h mean BP values of long-ter m SAD rats were not different from those of sham-operated rats, 24-h BPV of SAD rats was significantly higher than that of sham-operated rats. Arteria l baroreflex function in short-term SAD rats was significantly less than in sham-operated rats, whereas in long-term SAD rats, ABR-HP and ABR-BP were higher than those in short-term SAD rats, but were still significantly lowe r than those in control groups. At postoperative 18 weeks, baroreflex funct ion in SAD and AD rats was significantly less than function in SD and contr ol groups. SBPmax after phenylephrine and DBPmin after nitroprusside were s ignificantly higher in SAD, AD, and SD rats than in control rats. Barorefle x function was negatively correlated to DBPmin and SBP a in all denervated rats (n = 44). Some morphologic changes were found 18 weeks after denervati on in heart, kidney, and small artery in SAD, AD, and SD rats. Baroreflex f unction in all denervated rats was negatively related to 24-h BPV values. I n contrast, 24-h BPV values in SAD, AD, and SD rats were positively related to organ-damage score. A negative correlation between ABR function and end -organ damage score was found. Arterial baroreflex deficit played an indepe ndent and important role in organ-damage in SAD rats with significantly ele vated 24-h BPV.