Arterial Baroreceptor Reflex Counteracts Long-Term Blood Pressure Increase in the Rat Model of Renovascular Hypertension

Abstract

IntroductionThe present study tested the hypothesis that long-term effects of baroreceptor activation might contribute to the prevention of persistent arterial blood pressure (BP) increase in the rat model of renovascular hypertension (HTN).MethodsRepetitive arterial baroreflex (BR) testing was performed in normo- and hypertensive rats. The relationship between initial arterial BR sensitivity and severity of subsequently induced two-kidney one-clip (2K1C) renovascular HTN was studied in Wistar rats. Additionally, the time course of changes in systolic BP (SBP) and cardiac beat-to-beat (RR) interval was studied for 8 weeks after the induction of 2K1C renovascular HTN in the rats with and without sinoaortic denervation (SAD). In a separate experimental series, cervical sympathetic nerve activity (cSNA) was assessed in controls, 2K1C rats, WKY rats, and SHR.ResultsThe inverse correlation between arterial BR sensitivity and BP was observed in the hypertensive rats during repetitive arterial BR testing. The animals with greater initial arterial BR sensitivity developed lower BP values after renal artery clipping than those with lower initial arterial BR sensitivity. BP elevation during the first 8 weeks of renal artery clipping in 2K1C rats was associated with decreased sensitivity of arterial BR. Although SAD itself resulted only in greater BP variability but not in persistent BP rise, the subsequent renal artery clipping invariably resulted in the development of sustained HTN. The time to onset of HTN was found to be shorter in the rats with SAD than in those with intact baroreceptors. cSNA was significantly greater in the 2K1C rats than in controls.ConclusionsArterial BR appears to be an important mechanism of long-term regulation of BP, and is believed to be involved in the prevention of BP rise in the rat model of renovascular HTN.

Hypertension in rat offspring subjected to perinatal protein malnutrition is not related to the baroreflex dysfunction

“…Reports in the literature have suggested an association between baroreflex dysfunction and sympathetic overactivity, with subsequent development of hypertension . A different model, investigating the effects of a maternal obesogenic diet on offspring at 30 and 90 days of age, demonstrated that an obesogenic diet was able to induce high BP, autonomic imbalance, impaired baroreflex mechanism in 90 day‐old animals, suggesting that the sympathetic overactivity and hypertension in that model was due to baroreflex dysfunction, as also shown in other studies . So one of the hypotheses tested in our study was that the BR dysfunction might be involved in the onset of the hypertension in animals subjected to perinatal protein malnutrition.…”

“…14 and 90 days of age, demonstrated that an obesogenic diet was able to induce high BP, autonomic imbalance, impaired baroreflex mechanism in 90 day-old animals, 28 suggesting that the sympathetic overactivity and hypertension in that model was due to baroreflex dysfunction, as also shown in other studies. 21,29,30 So one of the hypotheses tested in our study was that the BR dysfunction might be involved in the onset of the hypertension in animals subjected to perinatal protein malnutrition. To test this, we applied different doses of vasoactive drugs, to provide different levels of activation and inhibition of the BR.…”

Electroacupuncture Improves Baroreflex and γ-Aminobutyric Acid Type B Receptor-Mediated Responses in the Nucleus Tractus Solitarii of Hypertensive Rats

“…The baroreflex is one of the most powerful and rapidly acting mechanisms for controlling arterial BP. It has been suggested that arterial baroreflex is involved in the long-term control of BP [ 30 ]. Several studies have shown that the sensitivity of the baroreflex is diminished in several forms of hypertension [ 22 , 31 , 32 ].…”

New Insights on the Maternal Diet Induced-Hypertension: Potential Role of the Phenotypic Plasticity and Sympathetic-Respiratory Overactivity

“…Although the relationship between maternal protein restriction and sympathetic overactivity have been suggested (Johansson et al, 2007 ; Franco et al, 2008 ; Barros et al, 2015 ), less is known about the physiological dysfunctions responsible for producing these effects. In this context, it is described that a baroreflex dysfunction could lead to a sympathetic overactivity and subsequent development of hypertension (Souza et al, 2001 ; Heusser et al, 2010 ; Tsyrlin et al, 2013 ). However, the hypothesis that maternal protein restriction leads to baroreflex dysfunction has not been proved yet.…”