Figure 1.

Orofacial operant test of orofacial mechanical sensitivity in animals of control and oxaliplatin-treated groups. (a) Left, the main parts of orofacial operant test device used to assess mechanical sensitivity in orofacial regions of rats. A mechanical stimulation module is placed in front of the nipple of a milk bottom. Right, enlarged image shows the mechanical stimulation module and a rat whose orofacial area is contacting mechanical stimulation filaments while drinking milk. (b) Two traces show contact events recorded over a 10-min session of operant test in a control animal injected with saline (top trace) and a different animal 30 days following oxaliplatin treatment (Oxa). Oxaliplatin is injected in five consecutive days at 2 mg/kg each injection. Saline is injected in the same manner as oxaliplatin injections. (c) Summary data of total contact time during a 10-min session orofacial operant test in different testing days in control group. Dashed line indicates the saline injections in five consecutive days. (d) Similar to (c) except data are obtained from oxaliplatin-treated animals. Dashed line indicates oxaliplatin injections in five consecutive days. In both (c) and (d), the number in each bar indicates the numbers of animals tested. Data represent Mean ± SEM, **p < .01, ***p < .001, compare with the data before the injections of saline or oxaliplatin.