Objective: Calcitonin gene-related peptide (CGRP) released following activation of trigeminovascular system (TVS) has a central role in migraine pathophysiology. Since CGRP is released from TVS through neurotransmitter exocytosis, mechanisms to limit neuronal excitability can modulate CGRP release. TRESK potassium-leak channels stabilize neuronal excitability by facilitating hyperpolarizing potassium outflow. We therefore investigated effects of TRESK channel activation on basal and capsaicininduced CGRP release from peripheral (duramater and trigeminal ganglion) and central (brainstem) structures of TVS in rats. Methods: Adult Wistar male rats were separated 4 groups (n=24). Due to bilateral location, two duramaters and trigemi nal ganglia (n=6, 3 rats) and one brainstem (n=6 rats) preparations were prepared from one rat. Preparations continuously carbogenized in artificial cerebrospinal-fluid were treated with TRESK activator cloxyquin(50 ve 100 μM) alone or in combination with TRPV1 agonist capsaicin (100 nM), TRESK inhibitor A2764 (100 μM) and anti-migraine drug sumatriptan (30 μM), respectively. CGRP contents in superfusates were measured by ELISA. Data were analyzed by one-way repeated measures ANOVA. Results: Capsaicin significantly induced CGRP release in duramater, trigeminal ganglion, and brainstem preparations compared to their controls, respectively (p<0.001). While both doses of cloxyquin significantly decreased capsaicin-induced CGRP release in these preparations (p<0.05), did not change baseline CGRP releases. A2764 reversed all effects of cloxyquin (p<0.01), confirming that the effect was due to activation of TRESK channels. While A2764 did not change basal CGRP release, it increased CGRP release compared to cloxyquin (p<0.05). Sumatriptan alone decreased capsaicin-induced CGRP release (p<0.05), while co-administered cloxyquin enhanced the effect of sumatriptan (p<0.05). Conclusion: Activation of TRESK channels by cloxyquin inhibits TRPV1-mediated CGRP release from trigeminal afferents, trigeminal ganglion and brainstem trigeminal nucleus that are involved in initiation and transmission of migraine pain by modulating neuronal excitability. TRESK channels may be a promising new target in preventing pathological release of CGRP, which is a migraine mediator and target of current anti-migraine drug researches. [ABSTRACT FROM AUTHOR]