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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.

Background Cardiovascular events (CVEs) occur more often in winter than in summer; however, the dependence of strokes on various meteorological factors remains unclear . Aims The purpose of this meta-analysis was to determine the dependence of the circannual dynamics of hospitalizations for hemorrhagic stroke (HS) and ischemic stroke (IS) on seasonal fluctuations in meteorological factors. Summary of review and conclusions For our meta-analysis, we selected 20 and 26 publications examining the seasonal dynamics of HS and IS, respectively . The meta-analysis showed that HS occurs more often in winter than in other seasons and does not depend on a region’s climate. The seasonal dynamics of IS are not clearly expressed and are determined by the characteristics of a region’s climate. In a climate without pronounced seasonal dynamics of atmospheric pressure and in wet winters, the vector of IS incidents will not be expressed or slightly shifted toward winter. Low atmospheric pressure in summer is associated with an increased likelihood of IS during this season compared to winter. There was also a relation between IS risk with high relative humidity and a significant decrease in ρO2 in summer, but there is not enough evidence regarding this association. We did not reveal dependence of the seasonal dynamics of strokes on the amplitude of annual fluctuations in air temperature. Keywords: ischemic stroke, hemorrhagic stroke, season, meteorological factors, climate

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