Licking responses of the p35 knockout mice during the orofacial operant assay. During the testing, the animals accessed the reward by inserting their snout through the plates with the different number of wires, in order to apply different force levels to the animal vibrissal pad. The number of beam breaks during the acquisition of the reward together with the licking time was measured: (A) without any stimulation, (B) using the plate with 6 + 6 wires, (C) 9 + 9 wires, and (D) 13 + 13. The data are expressed as mean ± SEM from four different animals, measured five times in case of the baseline, and three times after induction of the trigeminal nociception (unpaired t-test, ***p < 0.001). Two sample traces show the automatic recordings of drinking behavior in a testing period of 20 minutes in a single control (upper trace) and single p35 knockout mouse (lower trace).