Fig. 3.

The changes of RSNA, mean arterial pressure (MAP), and HR were measured in response to muscle stretch after B₂ receptor inhibition by HOE-140. Average data show that RSNA and MAP responses to muscle stretch were significantly attenuated in both control rats and ligated rats after blocking B₂ receptors. Note that the attenuating effects of HOE-140 appeared to be a greater degree in ligated group. The responses of RSNA and MAP returned to their pre-inhibitory state after a recovery period. No significant difference was observed in baseline MAP and HR in control rats and ligated rats. Also, there were no significant differences in signal-to-noise (S/N) ratio for the basal RSNA in control rats (3.5 ± 0.6) and ligated rats (3.6 ± 0.5, P > 0.05 vs. control). The reflex responses to muscle stretch with saline control were higher in ligated rats versus control animals. *P < 0.05 vs. saline control; †P < 0.05, significant differences in changes in RSNA and MAP between control group and ligated group. The number of animals is 11 in each group. Note that the same level of tension was loaded in all interventions.