Figure 1
Harmaline-induced Tremor Model in Pig. (A) Diagram of experimental design. Animals were acclimated to the accelerometer attachment and experimental environment before the recording session. Harmaline was repetitively injected three times at 2-day intervals. During the recording session, baseline (for 30 min) was recorded first and harmaline was injected through the intravenous (IV) line in the ear. (B) Photo of device attachment. Accelerometers and the IV line were attached and maintained throughout the recording session. (C) Raw tremor traces. Tremors were detected through the accelerometer attached on the limb. Rhythmic motion was significantly increased by harmaline injection (6 mg/kg). (D) Harmaline-induced tremor frequency. The predominant tremor frequency induced by harmaline is 10–16 Hz in pig. There is another significant tremor detected at 8–10 Hz.
Figure 2
Dose Dependence and Desensitization to Harmaline Effect. (A) Dose dependency of harmaline effect. Motion power ratio (MPR) was calculated by tremor with 10-minute epochs. The normalized MPR was obtained by dividing each MPR by the average of baseline MPR. Harmaline-induced tremor was dependent on the concentration of harmaline. Three different concentrations of harmaline were tested in pigs. The low concentration of harmaline (2.5 mg/kg) showed weaker MPR than the two higher concentrations (5.0 and 6.0 mg/kg) of harmaline. Light-grey dashed line indicates the point of harmaline injection. The error bars represent the standard error of the mean. (B) Desensitization to harmaline effect. The harmaline effect (6 mg/kg) was reduced by repetitive injections of harmaline. At the third injection, the onset-time of tremor induction was significantly delayed (70 minutes) and the maintained duration was decreased by 73.9 min (maintained only for 98.3 minutes). (C) Dose dependency of harmaline-induced tremor. Onset time of tremor, amplitude, maintained duration and frequency profile were analyzed. *p<0.05, ***p<0.0001.
