Figure 1

Verification that dual bilateral microinjections in the ventral medulla inhibits cardiac vagal outflow. A representative trace is provided in panel A showing that microinjection of muscimol (100 mM, 100 nl) into four regions of the medulla where bradycardia greater than 50 bpm was evoked by prior microinjection of L-glutamate (100 mM, 50 nl) increases resting heart rate (HR) and prevents baroreflex mediated bradycardia. Grouped data (n = 4) shows that microinjection of muscimol into these four sites evokes a large increase in HR (panel B) and dramatically reduces baroreflex sensitivity (BRS, panel C). * P < 0.05.