Evidence for increased extracellular K+ as an important mechanism for dorsal root induced alternating rhythmic activity in the neonatal rat spinal cord in vitro
Evidence for increased extracellular K+ as an important mechanism for dorsal root induced alternating rhythmic activity in the neonatal rat spinal cord in vitro
复制标题
DOI：
10.1016/s0304-3940(01)01777-3
复制
发表时间：
2001-05-18
影响因子：
2.5
通讯作者：
Nistri, A
中科院分区：
文献类型：
--
作者：
Marchetti, C;Beato, M;Nistri, A
大鼠腰椎运动神经元的细胞内记录显示，对一个背根的模式电刺激诱导了典型的有效运动的交替模式，并伴有超极化（AHP）后反峰的减少。由于AHP线性依赖于细胞外K+ ([K+](o))，从AHP下降中我们计算出[K+](o)上升到7.9 +/- 0.4 mM，这个值在7-10 mM范围内，已知会引起有效的运动。为了证实这种方法的特异性，我们还测试了n -甲基- d -天冬氨酸（2 muM）的浓度低于有效运动阈值，我们观察到，尽管有强烈的兴奋，估计的[K+](o)为6 mM，即在有效运动范围之外。我们认为，由传入纤维的某种电刺激模式引起的突触活动诱发了[K+](o)的持续升高，从而触发运动网络产生节律模式。(C) 2001爱思唯尔科学爱尔兰有限公司版权所有。
Intracellular recording from rat lumbar motoneurones showed that patterned electrical stimulation of one dorsal root induced alternating patterns typical of fictive locomotion, accompanied by a reduction in the antidromic spike afterhyperpolarization (AHP). Since the AHP depended linearly on extracellular K+ ([K+](o)), from the AHP fall we calculated that [K+](o) rose to 7.9 +/- 0.4 mM, a value within the 7-10 mM range known to elicit fictive locomotion. To confirm the specificity of this approach we also tested concentrations of N-methyl-D-aspartate (2 muM) below threshold for fictive locomotion, and we observed that, despite strong excitation, the estimated [K+](o) was 6 mM, i.e. outside the range for fictive locomotion. We suggest that synaptic activity induced by a certain pattern of electrical stimulation of afferent fibres evoked persistent elevation in [K+](o) which triggered the locomotor network to generate rhythmic patterns. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.