Receptive properties of mouse sensory neurons innervating hairy skin
Receptive properties of mouse sensory neurons innervating hairy skin
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DOI：
10.1152/jn.1997.78.4.1841
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发表时间：
1997-10-01
影响因子：
2.5
通讯作者：
Lewin, GR
中科院分区：
文献类型：
--
作者：
Koltzenburg, M;Stucky, CL;Lewin, GR
使用在体外神经皮肤制备和控制机械或热刺激，我们分析了277机械敏感的单一初级传入神经的接受特性与有髓（n = 251）或无髓（n = 26）轴突支配成年或2周龄小鼠的毛状皮肤。传入记录从小细丝的腓肠神经或隐神经在远交系小鼠品系或在近交系Balb/c株。根据它们的感受特性和传导速度，可以区分几种受体类型。在成年动物（>6周龄）中，54%的大型有髓纤维（A β，n = 83）对恒定力刺激表现出快速适应（RA）放电，并可能支配毛囊，而46%表现出缓慢适应（SA）反应，并可能支配触觉圆顶中的默克尔细胞。在细的有髓纤维（A δ，n = 91），34%是敏感的D毛受体和66%的高阈值机械感受器（AM纤维）。无髓纤维具有较高的机械阈值和伤害感受功能。所有的受体类型都有特征性的刺激反应功能，阈上力刺激。夜间热刺激（在皮肤的铈侧测量的从32到47摄氏度的15秒斜坡）激发了26%（19个中的5个）的AM纤维，阈值为42.5 +/- 1.4摄氏度（平均值+/- SE），平均放电15.8 +/- 9.7个动作电位，41%（7/17）C纤维，平均阈值37.6 +/-1.9摄氏度和22.0 +/- 6.0动作电位的平均放电。冷刺激能激活10条AM纤维中的1条和10条C纤维中的3条。10个C单位中的一个对热刺激和冷刺激都有反应。所有类型的传入纤维存在于成年小鼠可以很容易地识别在出生后第14天的小鼠。然而，纤维的传导速度降低，机械刺激的刺激反应功能更浅，在所有的纤维，除了D毛。在幼年小鼠中，22%的RA单位在高刺激强度下也显示SA反应;这些单位被称为RA/SA单位。我们的结论是，所有类型的皮肤传入纤维已经致力于他们的表型出生后2周，但在接下来的几周内进行一些成熟。该制剂具有很大的潜力，用于研究转基因小鼠的靶向突变的基因，编码的因素，参与指定的感觉神经元表型。
Using an in vitro nerve skin preparation and controlled mechanical or thermal stimuli, we analyzed the receptive properties of 277 mechanosensitive single primary afferents with myelinated (n = 251) or unmyelinated (n = 26) axons innervating the hairy skin in adult or 2-wk-old mice. Afferents were recorded from small filaments of either sural or saphenous nerves in an outbred mice strain or in the inbred Balb/c strain. On the basis of their receptive properties and conduction velocity, several receptor types could be distinguished. In adult animals (>6 wk old), 54% of the large myelinated fibers (A beta, n = 83) showed rapidly adapting (RA) discharges a to constant force stimuli and probably innervated hair follicles, whereas 46% displayed a slowly adapting (SA) response and probably innervated Merkel cells in touch domes. Among thin myelinated fibers (A delta, n = 91), 34% were sensitive D hair receptors and 66% were high-threshold mechanoreceptors (AM fibers). Unmyelinated fibers had high mechanical thresholds and nociceptive functions. All receptor types had characteristic stimulus-response functions to suprathreshold force stimuli. Noxious heat stimuli (15-s ramp from 32 to 47 degrees C measured at the cerium side of the skin) excited 26% (5 of 19) of AM fibers with a threshold of 42.5 +/- 1.4 degrees C (mean +/- SE) and an average discharge of 15.8 +/- 9.7 action potentials and 41% (7 of 17) C fibers with a mean threshold of 37.6 +/- 1.9 degrees C and an average discharge of 22.0 +/- 6.0 action potentials. Noxious cold stimuli activated 1 of 10 AM fibers and 3 of 10 C fibers. One of 10 C units responded to both heat and cold stimuli. All types of afferent fibers present in adult mice could readily be recognized in mice at postnatal day 14. However, fibers had reduced conduction velocities and the stimulus-response function to mechanical stimuli was more shallow in all fibers except for the D hairs. In juvenile mice, 22% of RA units also displayed an SA response at high stimulus intensities; these units were termed RA/SA units. We conclude that all types of cutaneous afferent fibers are already committed to their phenotype 2 wk after birth but undergo some maturation over the following weeks. This preparation has great potential for the study of transgenic mice with targeted mutations of genes that code factors that are involved in the specification of sensory neuron phenotypes.