Figure 3.

Rapid stimulation of mechanosensitive fibers by passive stretch produces the most robust increases in heart rate, blood pressure, and sympathetic nerve activity. Fast mechanostimulation produced significantly greater increases in blood pressure (A), heart rate (B), and RSNA (C) relative to both slow and medium stimulations. The increase in mechanical force (D) was the same for all three velocities of muscle deformation. The mean between the integrated blood pressure (E) and integrated heart rate (F) response to muscle deformation at different velocities was not statistically significant. Fast deformation decreased integrated RSNA (G) relative to both slow and medium deformations. The integrated mechanical force (H) was the same for all three velocities of muscle deformation. n = 7. *P < 0.05; **P < 0.01; ***P < 0.001. All data analyzed by one-way repeated-measures ANOVA followed by Tukey’s multiple comparison test. HR, heart rate; bpm, beats/min; MAP, mean arterial pressure; RSNA, renal sympathetic nerve activity.