Figure 3.

The magnitude of masseter muscle activation by glycinergic and GABAergic antagonists was unaffected by time. Group data (n = 11) demonstrating that strychnine, bicuculline, or strychnine/bicuculline perfusion into the left trigeminal motor pool increased left masseter EMG tone by the same magnitude at the beginning (white bars) and end (gray bars) of respective drug application periods. This finding demonstrates there was no time-dependent changes in antagonist efficacy. All measurements were taken during NREM sleep and values are mean ± SEM.