FIELD POTENTIALS GENERATED BY GROUP II MUSCLE AFFERENTS IN THE MIDDLE LUMBAR SEGMENTS OF THE CAT SPINAL-CORD
FIELD POTENTIALS GENERATED BY GROUP II MUSCLE AFFERENTS IN THE MIDDLE LUMBAR SEGMENTS OF THE CAT SPINAL-CORD
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DOI：
10.1113/jphysiol.1987.sp016498
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发表时间：
1987-04-01
影响因子：
5.5
通讯作者：
JANKOWSKA, E
中科院分区：
文献类型：
--
作者：
EDGLEY, SA;JANKOWSKA, E
用局灶性突触场电位记录证实了后肢肌肉的Ⅱ类肌传入纤维向腰髓第3、4、5节段的强有力投射。在两个位置发现了场电位：一个在背角（Rexed's laminae IV和V），另一个在中间区和腹角（Rexed's laminae VII和VIII）。在背角的场电位是非常大的，只引起第二组传入。在更腹侧的位置，他们是较小的，有时产生的小场电位诱发的I组传入。在这两个位置的场电位可以诱发的强度足以激活组II传入刺激的一些后肢肌肉神经。然而，一些神经始终诱发更强大的效果比别人和最大的电位是从神经到四头肌，缝匠肌和胫前屈肌（胫骨前肌和趾长伸肌）。激活关节传入（从膝关节神经）或环层小体传入（从骨间神经）诱发小场电位在某些位置。在背角的场电位的潜伏期是如此之短，他们必须产生单突触。在腹角的场电位有较长的潜伏期，由0.5-1.0毫秒，但他们也似乎已被缓慢进行脊髓内侧支单突触诱发。这一结论主要是基于椎管内刺激的影响，这被认为是逆向激活传入与适当的lavonium和阈值。有证据表明，背侧和腹侧场电位是由传入产生的，其受体可以被小（小于100 μ m）肌肉拉伸激活。
A powerful projection from group II muscle afferents of hind-limb muscles to the 3rd, 4th and 5th segments of the lumbar spinal cord has been demonstrated by focal synaptic field potential recording. Field potentials were found at two locations: one in the dorsal horn (Rexed''s laminae IV and V) and the other in the intermediate zone and ventral horn (Rexed''s laminae VII and VIII). In the dorsal horn the field potentials were exceptionally large and were evoked only by group II afferents. At more ventral locations, they were smaller and were sometimes produced by small field potentials evoked by group I afferents. At both locations field potentials could be evoked by stimulation of a number of hind-limb muscle nerves at strengths sufficient to activate group II afferents. However, some nerves consistently evoked more powerful effects than others and the largest potentials were from the nerves to quadriceps, sartorius and to the pretibial flexor muscles (tibialis anterior and extensor digitorum longus). Activation of articular afferents (from the knee joint nerve) or Pacinian corpuscle afferents (from the interosseous nerve) evoked small field potentials at some locations. In the dorsal horn the latency of the field potentials was so short that they must have been generated monosynaptically. Field potentials in the ventral horn had longer latencies, by 0.5-1.0 ms, but they also appear to have been monosynaptically evoked by slowly conducting intraspinal collaterals. This conclusion is based primarily on the effects of intraspinal stimulation which was found to antidromically activate afferents with the appropriate latencies and thresholds. Evidence is presented that the dorsal and ventral field potentials are generated by afferents whose receptors can be activated by small (less than 100 .mu.m) muscle stretches.