Figure 2.

Prevention of thermal allodynia by the H₄ receptor agonist VUF 8430 in SNI neuropathic mice. (A) SNI produced a long‐lasting thermal allodynia up to 25 days after surgery. (B) The H₄ receptor agonist VUF 8430 (10–40 μg per mouse i.t.) dose‐dependently reversed thermal allodynia in the ipsilateral side and increased pain threshold in the contralateral side, at 40 μg. (C) The antihyperalgesic effect of VUF 8430 (20 μg i.t.) was prevented by the H₄ receptor antagonist JNJ 10191584 (6 mg·kg⁻¹ p.o.) at any time point. (D) The antihyperalgesic effect of VUF 8430 was of intensity comparable with that produced by the reference drugs WIN55252‐2, MK‐801, α‐tocopherol and pregabalin. Amitriptyline was used as negative control. Data for reference drugs were recorded 30 min after the beginning of the test, except for pregabalin that was recorded after 3 h. Data points represent means ± SEM from experiments conducted on 10 mice. *P < 0.05 versus contralateral; #P < 0.05 versus ipsilateral before treatment; §P < 0.05 versus contralateral before treatment.