Role of K v7 potassium channels in the morphine-induced antinociception in acute and neuropathic pain [Akut ve Nöropatik Aĝr?da Morfine Baĝli{dotless} Antinosisepsiyonda K v7 Potasyum Kanallar?n?n Rol̈]

Objective: we aimed to investigate the role of k v7 potassium channels in the morphineinduced antinociception in both acute and neuropathic pain models. methods: neuropathic pain was induced by partial ligation of the right sciatic nerve. for intracerebroventricular (i.c.v.) injections,each rat was equipped with a permanent cannula. the response to painful thermal stimuli was assessed by the tail-flick test. in sciatic nerveligated rats,thermal hyperalgesia was assessed by paw withdrawal latencies in the plantar test and the mechanical hyperalgesia was determined by rigid von frey filaments. results: rats received morphine (2,5,20 μg/10 μl; i.c.v.) or saline (10 μl; i.c.v.) 15 min before the tests. in all tests,morphine produced significant antinociceptive effect. when a k v7 potassium channel blocker,linopirdine (0.1,1,10 μg/10 μl; i.c.v.) was administered 15 min before morphine,the effect of i.c.v. morphine in the tail-flick test and plantar test but not in the test with von frey filaments were prevented. conclusions: k v7 potassium channels contribute to the effect of i.c.v. morphine on acute pain induced by thermal stimulation. in the sciatic nerve-ligated rats,these channels play role in the effect of morphine on thermal hyperalgesia,but not on mechanical hyperalgesia.