Mechanical stimulation of the ulnar nerve suppresses cocaine-induced locomotor activity. (A) Mechanical stimulation (MS) of the ulnar site (Ulna MS; n = 6) significantly attenuated the locomotor response to cocaine, compared to the control group that received cocaine only (Con; n = 6) *p < 0.05 vs. Con; # p < 0.05 vs. Rad MS. Mechanical stimulation of the radial site (Rad MS; n = 6) did not alter cocaine-induced locomotion. (B) The inhibitory effect of ulnar MS on cocaine locomotion was not observed in rats with ulnar nerve injury (Ulna X + Ulna MS; n = 8) when compared to control rats with ulnar nerve injury (Ulna X; n = 8). The term ‘X’ denotes lesion or injury. (C) Ulna MS did not affect locomotion in the control rats injected with saline (Ulna MS; n = 5).