Excitatory neurotransmission activates voltage-dependent properties in neurons in spinal motor system of lamprey.
Excitatory neurotransmission activates voltage-dependent properties in neurons in spinal motor system of lamprey.
复制标题
兴奋性神经传递激活七鳃鳗脊髓运动系统神经元的电压依赖性特性。
DOI：
10.1152/jn.1989.62.2.334
复制
发表时间：
1989
影响因子：
2.5
通讯作者：
Sigvardt,KA
中科院分区：
文献类型：
--
作者：
Alford,S;Sigvardt,KA
1.在含士的宁的体外七鳃鳗脊髓尾鳍标本上，观察了感觉诱发节律性共激活时，腹角神经元在电压钳下的变化。2.在节律性共激活期间，在一定的保持电位范围内，电压钳在同一半节段显示出与腹根爆裂一致的内向电流，其表观翻转电位约为-10 mV。3.在该活动的每一次猝发中，峰值内向电流的电流-电压关系表现出明显的电压依赖性。4.内向电流的电压依赖性可被特异性的NMDA受体阻断剂APV和从浴液中去除镁离子所消除。5.在去极化电位下，可以观察到长时间的外向电流，表明K+和/或Cl-的表观电导与电压有关。这一电流也被APV阻断，并被镁离子的去除所增加。6.这些结果表明，在士的宁的节律性共激活期，兴奋性氨基酸递质的内源性释放通过激活NMDA受体而诱导腹角神经元的非线性电导特性。这些结果提供了额外的证据，证明这种激活有助于膜电位振荡，而膜电位振荡是节律性运动活动的基础。
1. Ventral horn neurons were studied under voltage clamp during episodes of sensory-evoked rhythmic coactivation in the in vitro lamprey spinal cord-tailfin preparation in the presence of strychnine. 2. Voltage clamp under a range of holding potentials during episodes of rhythmic coactivation revealed inward currents coincident with ventral root bursting in the same hemisegment and an apparent reversal potential of about -10 mV. 3. The current-voltage relationship of the peak inward current during each burst of this activity demonstrated a marked voltage dependency. 4. The voltage dependence of the inward current was eliminated by the specific NMDA-receptor blocker, APV, and by removal of Mg2+ from the bathing solution. 5. At depolarized potentials a long-lasting outward current could be observed, indicating an apparent voltage-dependent conductance for K+ and/or Cl-. This current was also blocked by APV and increased by the removal of Mg2+. 6. These results provide evidence that during rhythmic coactivation in strychnine, endogenous release of excitatory amino acid transmitter induces nonlinear conductance properties in ventral horn neurons by the activation of NMDA receptors. The results provide additional evidence that such activation contributes to the membrane potential oscillations that underlie rhythmic locomotory activity.