A&B) Two sample traces show contact events of orofacial operant tests at 12°C in a sham animal subcutaneously injected with vehicle (A) and a different sham animal subcutaneously injected with XE991 (B). C&D) Summary data of total contact time (C) and total contact numbers (D) during orofacial operant tests at 12°C. Open bar, vehicle-injected group; closed bar, XE991-injected group. In both C and D, the number in each bar indicates the numbers of animals tested. Orofacial operant tests were performed between 28 to 42 days after sham procedures. Data represent Mean ± SEM, *P < 0.05, comparing between XE991 and vehicle groups.