Reduction of baroreflex blood pressure oscillations in 12-month-old SHR: Central and peripheral mechanisms

The aim of this study was to reveal the changes of short-term cardiovascular variability in rats with sustained primary hypertension and correlate them with functional alterations of peripheral arteries. 12-month-old SHR as compared to Wistar rats demonstrated prominent reductions of mean arterial pressure and pulse interval spectral powers in the range 0.25-0.75 Hz. These alterations were associated with prominent reductions of cardiac baroreflex gain and constrictor responses of small arteries to electrical stimulation of sympathetic fibers and exogenous noradrenaline. We suggest that both central and peripheral mechanisms are responsible for the reduction of baroreflex arterial pressure oscillations in mature SHR.