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Arterial baroreceptor reflex counteracts long-term blood pressure increase in the rat model of renovascular hypertension.

Tsyrlin VA, Galagudza MM, Kuzmenko NV, Pliss MG, Rubanova NS, Shcherbin YI - PLoS ONE (2013)

Bottom Line: The 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).The animals with greater initial arterial BR sensitivity developed lower BP values after renal artery clipping than those with lower initial arterial BR sensitivity.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.

View Article: PubMed Central - PubMed

Affiliation: Institute of Experimental Medicine, V. A. Almazov Federal Heart, Blood and Endocrinology Centre, St-Petersburg, Russian Federation, St-Petersburg, Russian Federation. tsyrlin@almazovcentre.ru

ABSTRACT

Introduction: The 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).

Methods: Repetitive 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.

Results: The 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.

Conclusions: Arterial 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.

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Related in: MedlinePlus

The relationship between baroreflex (BR) sensitivity and systolic blood pressure (SBP) in the pooled samples of Wistar rats with stable hypertension (n = 10) and without hypertension (n = 10) 8 weeks after induction of two-kidney one-clip renovascular hypertension.The inverse correlation between BR sensitivity and SBP is observed (r = 0.69, p<0.01).
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getmorefigures.php?uid=PMC3675197&req=5

pone-0064788-g002: The relationship between baroreflex (BR) sensitivity and systolic blood pressure (SBP) in the pooled samples of Wistar rats with stable hypertension (n = 10) and without hypertension (n = 10) 8 weeks after induction of two-kidney one-clip renovascular hypertension.The inverse correlation between BR sensitivity and SBP is observed (r = 0.69, p<0.01).

Mentions: Eight weeks after surgery, 20 animals were randomly chosen from the groups with stable HTN and without HTN for chronic instrumentation and arterial BR testing. 10 animals were sampled from stable HTN cohort and 10 more animals from the group without HTN. We considered unnecessary to instrumentalize all animals (n = 59) since, according to our preliminary estimates, the sample size of 20 would be enough to get a statistically meaningful result. Arterial BR sensitivity in the animals with stable HTN and without HTN averaged 0.35±0.12 and 0.78±0.18 ms/mm Hg, respectively (p<0.05). Notably, arterial BR sensitivity in the rats without HTN was similar to that in sham-operated animals (0.81±0.21 ms/mm Hg). Fig. 2 illustrates the presence of a significant inverse correlation between arterial BR sensitivity and SBP in the pooled sample of animals consisting of 10 rats each with stable HTN and without HTN (r = 0.69, p<0.01).


Arterial baroreceptor reflex counteracts long-term blood pressure increase in the rat model of renovascular hypertension.

Tsyrlin VA, Galagudza MM, Kuzmenko NV, Pliss MG, Rubanova NS, Shcherbin YI - PLoS ONE (2013)

The relationship between baroreflex (BR) sensitivity and systolic blood pressure (SBP) in the pooled samples of Wistar rats with stable hypertension (n = 10) and without hypertension (n = 10) 8 weeks after induction of two-kidney one-clip renovascular hypertension.The inverse correlation between BR sensitivity and SBP is observed (r = 0.69, p<0.01).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3675197&req=5

pone-0064788-g002: The relationship between baroreflex (BR) sensitivity and systolic blood pressure (SBP) in the pooled samples of Wistar rats with stable hypertension (n = 10) and without hypertension (n = 10) 8 weeks after induction of two-kidney one-clip renovascular hypertension.The inverse correlation between BR sensitivity and SBP is observed (r = 0.69, p<0.01).
Mentions: Eight weeks after surgery, 20 animals were randomly chosen from the groups with stable HTN and without HTN for chronic instrumentation and arterial BR testing. 10 animals were sampled from stable HTN cohort and 10 more animals from the group without HTN. We considered unnecessary to instrumentalize all animals (n = 59) since, according to our preliminary estimates, the sample size of 20 would be enough to get a statistically meaningful result. Arterial BR sensitivity in the animals with stable HTN and without HTN averaged 0.35±0.12 and 0.78±0.18 ms/mm Hg, respectively (p<0.05). Notably, arterial BR sensitivity in the rats without HTN was similar to that in sham-operated animals (0.81±0.21 ms/mm Hg). Fig. 2 illustrates the presence of a significant inverse correlation between arterial BR sensitivity and SBP in the pooled sample of animals consisting of 10 rats each with stable HTN and without HTN (r = 0.69, p<0.01).

Bottom Line: The 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).The animals with greater initial arterial BR sensitivity developed lower BP values after renal artery clipping than those with lower initial arterial BR sensitivity.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.

View Article: PubMed Central - PubMed

Affiliation: Institute of Experimental Medicine, V. A. Almazov Federal Heart, Blood and Endocrinology Centre, St-Petersburg, Russian Federation, St-Petersburg, Russian Federation. tsyrlin@almazovcentre.ru

ABSTRACT

Introduction: The 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).

Methods: Repetitive 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.

Results: The 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.

Conclusions: Arterial 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.

Show MeSH
Related in: MedlinePlus