RESUMEN
AIM: To investigate the changes of vascular systiolic/relaxant function in sino-aortic denervated rats. METHODS: Male Sprague-Dawley rats were underwent sino-aortic denervation (SAD). The sinoaortic denervated (SAD) rats were adopted as a model of arterial baroreflex deficit. SAD, isolated aortic-denervated (AD) and isolated sinus-denervated (SD) rats were instrumented chronically to record blood pressure (BP), heart rate (HR), BP variability (BPV), HR variability (HRV), arterial baroreflex function control of heart period (ABR-HP) and BP (ABR-BP). The vascular maximum contractile/relaxant function was determined through cumulative venous injection of phenylephrine (SBPmax) and nitroprusside(DBPmin) both after ganglionic blokade. RESULTS: Acute SAD(1 week after operation) caused hypertension and tachycardia in rats. Eighteen weeks after operation, BP and HR values in SAD and SD rats were not different from those in sham-operated rats, but AD rats were hypertensive compared with control group. Though the 24 h mean BP values of chronic (18 weeks after operation) SAD rats was not different from those in the sham-operated rats, 24 h BPV of SAD rats was significantly higher when compared with sham-operated rats. ABR function in the acute SAD rats was significantly decreased when compared with sham-operated rats, whereas in chronic SAD rats, both ABR-HP and ABR-BP were higher than those in acute SAD rats, but were still significantly lower than those in control groups. 18 weeks after operation, ABR function in SAD and AD rats were significantly decreased when compared with those in SD and control groups. SBPmax after phenylephrine and DBPmin after nitroprusside were significantly higher in SAD, AD and SD rats than in control group. ABR function was negatively correlated to DBPmin(r = -0.677 for ABR-HP, and r = -0.681 for ABR-BP; P<0.001) and SBPmax(r = -0.614 for. ABR-HP, and r = -0.545 for ABR-BP; P< 0.001) in the whole group of the denervated rats (n = 44). ABR function of the sino-aortic denervated rats was negatively related to the 24 h BPV. CONCLUSION: Remarkable changes of vascular systolic/ relaxant dysfunction are observe in sino-aortic denervated rats 18 weeks after operation, and this effect is closely relate to the decreased ABR function and increase 24 h BPV.