Hori N, Carp J S, Carpenter D O, Akaike N
School of Public Health, University at Albany, One University Place, Rm. B242 Rensselaer, NY 12144-3456, USA.
Life Sci. 2002 Dec 20;72(4-5):389-96. doi: 10.1016/s0024-3205(02)02279-8.
Cervical spinal cord slices were prepared from adult rats. Intracellular recordings from motoneurons revealed that electrical stimulation of the ventralmost part of the dorsal funiculus (which contains primarily descending corticospinal axons) elicited EPSPs in 75% of the neurons. The latencies of these EPSPs tended to be shorter than those elicited by dorsal horn gray matter stimulation. Pairs of subthreshold dorsal funiculus stimuli were able to elicit action potentials in motoneurons. These data are consistent with previous morphological and electrophysiological studies indicating that cervical motoneurons receive both mono-and polysynaptic corticospinal inputs. In addition, motoneurons were markedly depolarized by iontophoretic application of AMPA or KA (7 out of 7 neurons), but only weakly depolarized by NMDA (1 out of 6 neurons). CNQX (but not AP-5) blocked EPSPs elicited by dorsal funiculus stimulation. Thus, corticospinal transmission to motoneurons is mediated primarily by non-NMDA glutamate receptors.
从成年大鼠制备颈脊髓切片。对运动神经元进行细胞内记录发现，电刺激背侧索最腹侧部分（主要包含下行皮质脊髓轴突）可在75%的神经元中诱发兴奋性突触后电位（EPSP）。这些EPSP的潜伏期往往比背角灰质刺激所诱发的潜伏期短。成对的阈下背侧索刺激能够在运动神经元中诱发动作电位。这些数据与先前的形态学和电生理学研究一致，表明颈段运动神经元接受单突触和多突触皮质脊髓输入。此外，通过离子电泳施加AMPA或KA（7个神经元中的7个）可使运动神经元明显去极化，但通过NMDA（6个神经元中的1个）仅使其轻微去极化。CNQX（而非AP - 5）阻断了背侧索刺激所诱发的EPSP。因此，皮质脊髓向运动神经元的传递主要由非NMDA谷氨酸受体介导。
