Catterall William A, Dib-Hajj Sulayman, Meisler Miriam H, Pietrobon Daniela
Department of Pharmacology, University of Washington, Seattle, Washington 98195-7280, USA.
J Neurosci. 2008 Nov 12;28(46):11768-77. doi: 10.1523/JNEUROSCI.3901-08.2008.
Studies of genetic forms of epilepsy, chronic pain, and migraine caused by mutations in ion channels have given crucial insights into molecular mechanisms, pathogenesis, and therapeutic approaches to complex neurological disorders. Gain-of-function missense mutations in the brain type-I sodium channel Na(V)1.1 are a primary cause of generalized epilepsy with febrile seizures plus. Loss-of-function mutations in Na(V)1.1 channels cause severe myoclonic epilepsy of infancy, an intractable childhood epilepsy. Studies of a mouse model show that this disease is caused by selective loss of sodium current and excitability of GABAergic inhibitory interneurons, which leads to hyperexcitability, epilepsy, and ataxia. Mutations in the peripheral sodium channel Na(V)1.7 cause familial pain syndromes. Gain-of-function mutations cause erythromelalgia and paroxysmal extreme pain disorder as a result of hyperexcitability of sensory neurons, whereas loss-of-function mutations cause congenital indifference to pain because of attenuation of action potential firing. These experiments have defined correlations between genotype and phenotype in chronic pain diseases and focused attention on Na(V)1.7 as a therapeutic target. Familial hemiplegic migraine is caused by mutations in the calcium channel, Ca(V)2.1, which conducts P/Q-type calcium currents that initiate neurotransmitter release. These mutations increase activation at negative membrane potentials and increase evoked neurotransmitter release at cortical glutamatergic synapses. Studies of a mouse genetic model show that these gain-of-function effects lead to cortical spreading depression, aura, and potentially migraine. Overall, these experiments indicate that imbalance in the activity of excitatory and inhibitory neurons is an important underlying cause of these diseases.
对由离子通道突变引起的癫痫、慢性疼痛和偏头痛的遗传形式的研究，为复杂神经系统疾病的分子机制、发病机制和治疗方法提供了关键见解。脑I型钠通道Na(V)1.1中的功能获得性错义突变是伴有热性惊厥附加症的全身性癫痫的主要病因。Na(V)1.1通道的功能丧失性突变会导致婴儿严重肌阵挛性癫痫，这是一种难治性儿童癫痫。对小鼠模型的研究表明，这种疾病是由GABA能抑制性中间神经元的钠电流和兴奋性选择性丧失引起的，这会导致过度兴奋、癫痫和共济失调。外周钠通道Na(V)1.7的突变会导致家族性疼痛综合征。功能获得性突变会导致红斑性肢痛症和阵发性极端疼痛障碍，这是由于感觉神经元过度兴奋所致，而功能丧失性突变会导致先天性无痛觉，这是由于动作电位发放减弱所致。这些实验确定了慢性疼痛疾病中基因型与表型之间的相关性，并将注意力集中在Na(V)1.7作为治疗靶点上。家族性偏瘫性偏头痛是由钙通道Ca(V)2.1的突变引起的，该通道传导启动神经递质释放的P/Q型钙电流。这些突变增加了负膜电位下的激活，并增加了皮质谷氨酸能突触处诱发的神经递质释放。对小鼠遗传模型的研究表明，这些功能获得性效应会导致皮质扩散性抑制、先兆，甚至可能引发偏头痛。总体而言，这些实验表明兴奋性和抑制性神经元活动的失衡是这些疾病的一个重要潜在病因。
