Limits...
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.

Show MeSH

Related in: MedlinePlus

Cervical sympathetic nerve activity (left) and integrated electrical activity of cervical sympathetic nerve (right).A: Normotensive Wistar rats (n = 6). B: Wistar rats with two-kidney one-clip renovascular hypertension (n = 6). C: Wistar-Kyoto rats (n = 6). D: Spontaneously hypertensive rats (n = 7).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3675197&req=5

pone-0064788-g004: Cervical sympathetic nerve activity (left) and integrated electrical activity of cervical sympathetic nerve (right).A: Normotensive Wistar rats (n = 6). B: Wistar rats with two-kidney one-clip renovascular hypertension (n = 6). C: Wistar-Kyoto rats (n = 6). D: Spontaneously hypertensive rats (n = 7).

Mentions: Integrated spontaneous cSNA in normotensive Wistar rats averaged 98.7±22.07 µV×s. This parameter was significantly higher in the animals with 2K1C HTN (191.5±29.31 µV×s, p<0.05 versus sham-operated rats, Fig. 4). Integrated spontaneous cSNA in the WKY and SHR rats was 181.6±46.67 and 479.0±84.93 µV×s, respectively (p<0.05). Amplitude analysis of cSNA showed that low-amplitude (2–5 µV) electrical activity appeared to be most prevalent in both normo- and hypertensive rats. However, the relative contribution of mid- (5 to 10 µV) and high-amplitude (>10 µV) electrical activity was greater in hypertensive rats than in normotensive ones. For example, the contribution of mid- and high-amplitude activity to the total cSNA in 2K1C group was, respectively, 3 and 1.5 times higher than that in the sham-treated animals (Table 2). Moreover, the contribution of mid- and high-amplitude activity was significantly higher in SHR than in the WKY rats, thereby reflecting the greater sympathetic activation in the former (Table 2).


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)

Cervical sympathetic nerve activity (left) and integrated electrical activity of cervical sympathetic nerve (right).A: Normotensive Wistar rats (n = 6). B: Wistar rats with two-kidney one-clip renovascular hypertension (n = 6). C: Wistar-Kyoto rats (n = 6). D: Spontaneously hypertensive rats (n = 7).
© Copyright Policy
Related In: Results  -  Collection

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

pone-0064788-g004: Cervical sympathetic nerve activity (left) and integrated electrical activity of cervical sympathetic nerve (right).A: Normotensive Wistar rats (n = 6). B: Wistar rats with two-kidney one-clip renovascular hypertension (n = 6). C: Wistar-Kyoto rats (n = 6). D: Spontaneously hypertensive rats (n = 7).
Mentions: Integrated spontaneous cSNA in normotensive Wistar rats averaged 98.7±22.07 µV×s. This parameter was significantly higher in the animals with 2K1C HTN (191.5±29.31 µV×s, p<0.05 versus sham-operated rats, Fig. 4). Integrated spontaneous cSNA in the WKY and SHR rats was 181.6±46.67 and 479.0±84.93 µV×s, respectively (p<0.05). Amplitude analysis of cSNA showed that low-amplitude (2–5 µV) electrical activity appeared to be most prevalent in both normo- and hypertensive rats. However, the relative contribution of mid- (5 to 10 µV) and high-amplitude (>10 µV) electrical activity was greater in hypertensive rats than in normotensive ones. For example, the contribution of mid- and high-amplitude activity to the total cSNA in 2K1C group was, respectively, 3 and 1.5 times higher than that in the sham-treated animals (Table 2). Moreover, the contribution of mid- and high-amplitude activity was significantly higher in SHR than in the WKY rats, thereby reflecting the greater sympathetic activation in the former (Table 2).

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