Figure 4. Effects of sympathetic stimulation alone (A), of SCh injection alone (B) and of combined SCh injection and sympathetic stimulation (C) on the discharge of a Ia MSA located in the masseter muscle.
Below each trial is the tension signal detected by the puller (calibration: 200 g); stretch amplitude: 2 mm. Sympathetic stimulation at 10 impulses s−1, lasting 90 s, is marked by horizontal bars. SCh administration 200 μg kg−1i.v. is marked by the arrows. Time constant used for integration: 500 ms.