Migraine is caused by hyperactivity of the trigeminovascular system, where trigeminal ganglia (TG) play an important role. This hyperactivity might originate from an underfunctional GABAergic system in TG. To investigate this possibility, we adapted a mouse model of migraine by inducing migraine-like grimaces in male mice via repeated injections of nitroglycerin (NTG, 10 mg/kg, i.p.), once every 2 days, for up to 5 sessions. Migraine-like facial pain scores were measured using the mouse grimace scale. Repeated NTG treatments in mice caused significant increases in migraine-like grimaces that were aborted and prevented by two anti-migraine agents sumatriptan and topiramate, respectively. After 5 sessions of NTG injections, the GABA-synthesizing enzyme, 65-kDa glutamate decarboxylase (GAD65), but not the GABA transporter 1 (GAT1) or the α6 subunit-containing GABA_A receptors (α6GABA_ARs), was downregulated in mouse TG tissues. Taking advantage of the unaffected TG α6GABA_AR expression in NTG-treated mice, we demonstrated that an α6GABA_AR-selective positive allosteric modulator (PAM), DK-I-56-1, exhibited both abortive and prophylactic effects, comparable to those of sumatriptan and topiramate, respectively, in this migraine-mimicking mouse model. The brain-impermeable furosemide significantly prevented the effects of DK-I-56-1, suggesting its peripheral site of action, likely via preventing α6GABA_AR modulation in TG. Results suggest that a decreased GABA synthesis caused by the reduced GAD65 expression in TG contributes to the trigeminovascular activation in this repeated NTG-induced migraine-mimicking model and that the unaltered α6GABA_ARs in TG are potential targets for migraine treatment. Thus, α6GABA_AR-selective PAMs are potential anti-migraine agents for both abortive and preventive therapies.

偏头痛是由三叉神经血管系统过度活跃引起的，其中三叉神经节 (TG) 在其中发挥重要作用。这种过度活跃可能源于 TG 中功能不足的 GABA 能系统。为了研究这种可能性，我们通过重复注射硝酸甘油（NTG，10 毫克/千克，腹腔注射），每 2 天一次，最多 5 次，通过诱导雄性小鼠出现偏头痛样鬼脸来调整偏头痛小鼠模型。使用小鼠鬼脸量表测量偏头痛样面部疼痛评分。在小鼠中重复 NTG 治疗导致偏头痛样鬼脸的显着增加，这些鬼脸分别被两种抗偏头痛药物舒马曲坦和托吡酯中止和预防。注射 5 次 NTG 后，合成 GABA 的酶、65-kDa 谷氨酸脱羧酶 (GAD65)、_A受体（α6GABA _A Rs）在小鼠 TG 组织中下调。利用NTG 处理小鼠中未受影响的 TG α6GABA _A R 表达，我们证明了 α6GABA _A R 选择性正变构调节剂 (PAM) DK-I-56-1 表现出与那些相当的流产和预防作用舒马曲坦和托吡酯分别在这个模拟偏头痛的小鼠模型中。不透脑的呋塞米显着阻止了 DK-I-56-1 的作用，表明其作用于外周部位，可能是通过阻止 α6GABA _ATG 中的 R 调制。结果表明，在这种重复的 NTG 诱导的偏头痛模拟模型中，由 TG 中 GAD65 表达降低引起的 GABA 合成减少有助于三叉神经血管激活，并且TG 中未改变的 α6GABA _A Rs 是偏头痛治疗的潜在目标。因此，α6GABA _A R 选择性 PAM 是用于流产和预防治疗的潜在抗偏头痛药物。