Hyperleptinemia increases the susceptibility of the cortex to generate cortical spreading depression

Background Obesity is a risk factor for episodic migraine to develop into chronic migraine; hence, it is speculated that obesity and hyperleptinemia are associated with migraine. We hypothesized that leptin is involved in the mechanisms of cortical spreading depression (CSD). Therefore, we examined whether leptin affected a rat model of CSD to clarify the relationship between leptin and migraine. Methods We evaluated the effect of intracerebroventricular (ICV) administration of leptin on a rat CSD model. We then examined whether once-a-day intraperitoneal administration of leptin for seven days (as a chronic hyperleptinemia model) affected rat CSD models. Finally, we induced CSD in Zucker fatty (ZF) rats, which is a well-known model of obesity. Results In the parietal cortex, the percent change in cerebral blood flow and direct current (DC) potential decreased after ICV administration of leptin. A similar decrease in DC potential was observed in rats treated with intraperitoneal leptin. The number of CSDs increased significantly in rats given intraperitoneal leptin and in ZF rats. Conclusions The present study suggests that leptin is involved in the mechanisms of CSD.