FMRFamide-related peptide expression in the vestibular-afferent neurons

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• 作者：Francisco Mercado^a ; ^c ; Iv&#225 ; n Ló ; pez^b ; Aida Ortega^a ; Angé ; lica Almanza^a ; Enrique Soto^a ; Rosario Vega^a ; ^{axolotl_56@yahoo.com.mx}
• 关键词：RF-amide ; Semicircular canal ; Hair cell ; ASIC ; Amiloride ; Afferent synapse
• 刊名：Neuroscience Letters
• 出版年：2012
• 期刊代码：52_03043940
• 类别：neu
• 出版时间：28 March, 2012
• 卷：513
• 期：1
• 页码：12-16
• 文件大小：532 K

摘要

Vestibular-afferent neurons innervate hair cells from the sensory epithelia of vestibular end-organs and their action-potential discharge dynamics are driven by linear and angular accelerations of the head. The electrical activity of the vestibular-afferent neurons depends on their intrinsic properties and on the synaptic input from hair cells and from the terminals of the efferent system. Here we report that vestibular-afferent neurons of the rat are immunoreactive to RFamide-related peptides, and that the stronger signal comes from calyx-shaped neuron dendrites, with no signal detected in hair cells or supporting cells. The whole-cell voltage clamp recording of isolated afferent neurons showed that they express robust acid-sensing ionic currents (ASICs). Extracellular multiunit recordings of the vestibular nerve in a preparation in vitro of the rat inner ear showed that the perfusion of FMRFamide (a snail ortholog of this family of neuropeptides) exerts an excitatory effect on the afferent-neurons spike-discharge rate. Because the FMRFamide cannot activate the ASIC but reduces its desensitization generating a more robust current, its effect indicates that the ASIC are tonically active in the vestibular-afferent neurons and modulated by RFamide-like peptides.