Icilin‐induced “wet‐dog” shaking in rats

Icilin, a TRPM8 agonist, was used to induce shaking in rats (Wei, 1983). Animals were first habituated to the testing room for 30 min; after that, they were randomized into treatment groups and treated with vehicle (p.o. or i.v.) or DFL23693 (10 mg·kg⁻¹ p.o.) or with DFL23488 (10 mg·kg⁻¹ i.v.). Icilin was administered i.p. at 1 mg·kg⁻¹ dissolved in 1% Tween80/H₂O. The number of intermittent but rhythmic ‘wet dog‐like’ shakes (WDS) of neck, head and trunk in each animal was counted for a period of 30 min following icilin administration. DFL23693 and DFL 23448 were, respectively, administered 3 and 1 h before icilin injection.