Fig. 4.

Dlow have a reduced cardiac response to experimentally-induced baroreflex. A. Representative traces showing the global cardiac modification induced by sodium nitroprusside (SNP) followed by phenylephrine (PE). B. The maximal baroreflex cardiac response (BRR: ΔHR/ΔMBP) was reduced in Dlow compared to ND and Dhigh rats. Box and whisker graphs indicate the minimum and maximum values and the median. ***p < 0.001 versus ND. ^###p < 0.001 versus Dlow. C. C1: Curves of cardiac baroreceptor gain. Reflex fall in HR (y-axis) in response to increase in MBP (x-axis) triggered by SNP + PE administration is lower in Dlow than in Dhigh and ND. Parameters of the baroreceptor curves for ND, Dlow and Dhigh rats are given in Table. C2: Slopes were calculated by regression analysis of the rectilinear part of the baroreceptor curves. Slope in Dlow is lower than in Dhigh and ND.