SOMAL MEMBRANE-PROPERTIES OF PHYSIOLOGICALLY IDENTIFIED SENSORY NEURONS IN THE RAT - EFFECTS OF NERVE GROWTH-FACTOR
SOMAL MEMBRANE-PROPERTIES OF PHYSIOLOGICALLY IDENTIFIED SENSORY NEURONS IN THE RAT - EFFECTS OF NERVE GROWTH-FACTOR
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DOI：
10.1152/jn.1992.68.6.2033
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发表时间：
1992-12-01
影响因子：
2.5
通讯作者：
MENDELL, LM
中科院分区：
文献类型：
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作者：
RITTER, AM;MENDELL, LM
1.方法：1.对5-8周龄未治疗大鼠和从出生到5周龄用神经生长因子（NGF）或抗NGF血清（anti-NGF）治疗的大鼠的生理学鉴定的背根神经节（DRG）细胞进行原位细胞内记录.如猫所示，正常大鼠背根节细胞的体细胞动作电位（AP）的形状与外周受体类型相关。神经支配高阈值机械感受器（HTMR）的细胞，从而对周围皮肤或深部组织的有害刺激作出反应，这些细胞具有长持续时间的AP，其特征在于尖峰的失败肢体上的拐点。神经支配低阈值机械感受器（LTMR）的细胞具有缺乏拐点的较短AP。与支配LTMR的神经元相比，支配HTMR的神经元的躯体AP的幅度更大，峰值上升速率更慢，平均后超极化时间更长.还发现HTMR的体AP不被直接施加到神经节表面的200 μ M河豚毒素（TTX）阻断。相反，LTMR的那些被迅速且不可逆地阻断。尽管索马的敏感性不同，但两种类型细胞的轴突传导均被TTX消除。与未治疗的对照动物或用免疫前兔血清治疗的动物相比，用NGF慢性治疗导致尖峰下降肢体的持续时间增加。这仅在开始具有长持续时间AP的小区中是真实的，即，HTMR。LTMR不受给药影响。相反，用抗NGF治疗引起下降时间的小但显著的减少，但仅在Abeta HTMR中。同样，LTMR不受治疗的影响。我们的结论是，在体内的神经生长因子可以有小的影响与有髓轴突的背根神经节细胞的体膜特性。然而，在这些细胞中，这些作用是特定于单个生理组的细胞，HTMR。
1. Intracellular recordings were made in situ from physiologically identified dorsal root ganglion (DRG) cells in untreated rats aged 5-8 wk and in rats treated from birth to 5 wk of age with nerve growth factor (NGF) or antisera against NGF (anti-NGF).2. As demonstrated in cats, the shape of the somal action potential (AP) of DRG cells of normal rats is correlated with peripheral receptor type. Cells that innervate high-threshold mechanoreceptors (HTMRs) and thus respond to noxious stimulation of skin or deep tissue in the periphery have long-duration APs characterized by an inflection on the failing limb of the spike. Cells that innervate low-threshold mechanoreceptors (LTMRs) have briefer APs that lack the inflection. Somal APs of neurons supplying HTMRs tend to be larger in amplitude, have slower peak rates of rise, and on average have longer afterhyperpolarizations than those innervating LTMRs.3. It was also found that the somal APs of HTMRs were not blocked by 200 muM tetrodotoxin (TTX) applied directly to the surface of the ganglion. In contrast, those of LTMRs were rapidly and irreversibly blocked. Despite the difference in the sensitivity of the soma, axonal conduction in both types of cells was abolished by TTX.4. Chronic treatment with NGF resulted in an increase in duration of the falling limb of the spike compared with untreated control animals or animals treated with preimmune rabbit serum. This was true only in cells that had long duration APs to begin with, i.e., HTMRs. LTMRs were unaffected by the treatment. Conversely, treatment with anti-NGF caused a small but significant decrease in fall time, but only in Abeta HTMRs. Again, LTMRs were unaffected by the treatment.5. We conclude that in vivo NGF can have small effects on somal membrane properties of DRG cells with myelinated axons. However, among these cells, these actions are specific for a single physiological group of cells, HTMRs.