The electrophysiological properties of 87 neurons in the deep dorsal horn (laminae III-VI) of the rat spinal cord have been investigated in vitro. Two preparations have been used; the transverse spinal cord slice preparation from the third or fourth lumbar segments of 14-16-day-old rats (71 cells) and a hemisected lumbar spinal cord preparation from 10-12-day-old rats (16 cells). The input impedances (range 11-128 M omega), membrane potentials (-67 +/- 8 mV S.D.), action potential amplitude (77 +/- 11.8 mV) duration (1.4 +/- 0.5 ms) and afterpotentials, were effectively identical in the neurons recorded from the two preparations. Neurons in both preparations when activated with long-duration (1-2 s) outward current pulses showed a single steady-state firing range with little adaptation of firing frequency or action potential amplitude. This pattern of responses was unaffected by changing the membrane potential. Orthodromic synaptic activity could be elicited in the neurons by stimulating either the small dorsal root remnants in the slice or the dorsal roots in the hemisected spinal cord. The responses evoked by single stimuli of increasing intensity varied in different neurons in both preparations. The commonest response (32/62) consisted of a short-latency, short-duration composite excitatory postsynaptic potential which generated one or two spikes with no further spiking activity at longer latency when the stimulus intensity was increased beyond threshold. In 20 neurons, graded stimulation produced a graded response with recruitment, at high intensities, of a discharge of action potentials lasting several hundred milliseconds. A small number of cells (4) responded to the single stimulus with a train of action potentials lasting several seconds. Stimulating adjacent dorsal roots in the hemisected cord preparation could evoke quite different responses from the neurons. The heterogeneity of the types of orthodromic responses obtained in both preparations, in spite of the almost uniform intrinsic membrane properties, is likely to reflect differences in the strength, location and type of afferent and interneuronal input to different dorsal horn cells.

译文

已在体外研究了大鼠脊髓深背角 (laminae iii-vi) 中87个神经元的电生理特性。已使用两种制剂; 来自14-16天大的大鼠 (71个细胞) 的第三或第四腰椎节段的横向脊髓切片制剂和来自10-12天大的大鼠 (16个细胞) 的半腰脊髓制剂。输入阻抗 (范围11-128 M omega),膜电位 (-67 +/- 8 mV s.d.),动作电位振幅 (77 +/- 11.8 mV) 持续时间 (1.4 +/- 0.5 ms) 和后电位,两种制剂记录的神经元实际上是相同的。用长时间 (1-2 s) 的向外电流脉冲激活时,两种制剂中的神经元均显示出单一的稳态发射范围,几乎不适应发射频率或动作电位幅度。这种反应模式不受改变膜电位的影响。通过刺激切片中的小背根残余物或半脊髓中的背根,可以在神经元中引发正畸突触活动。在两种制剂中,强度增加的单个刺激引起的反应在不同的神经元中有所不同。最常见的反应 (32/62) 由短潜伏期,短持续时间的复合兴奋性突触后电位组成,当刺激强度增加超过阈值时,在更长的潜伏期产生一个或两个尖峰,而没有进一步的尖峰活动。在20个神经元中,分级刺激产生了分级反应,并在高强度下募集了持续数百毫秒的动作电位放电。少数细胞 (4) 对单个刺激有反应,持续了几秒钟的动作电位。在半切除的脐带制剂中刺激相邻的背根可能会引起神经元的完全不同的反应。尽管具有几乎均匀的固有膜特性,但在两种制剂中获得的正畸反应类型的异质性可能反映了不同背角细胞的传入和神经元输入的强度,位置和类型的差异。

+1
+2
100研值 100研值 ¥99课程
检索文献一次
下载文献一次

去下载>

成功解锁2个技能,为你点赞

《SCI写作十大必备语法》
解决你的SCI语法难题!

技能熟练度+1

视频课《玩转文献检索》
让你成为检索达人!

恭喜完成新手挑战

手机微信扫一扫,添加好友领取

免费领《Endnote文献管理工具+教程》

微信扫码, 免费领取

手机登录

获取验证码
登录