Otsuka M, Konishi S, Takahashi T
Fed Proc. 1975 Sep;34(10):1922-8.
A peptide that exerts a depolarizing action on frog spinal motoneurons was found in the dorsal root of bovine spinal nerve. Pharmacological, chemical, and immunological properties of this motoneuron-depolarizing peptide were investigated and the results indicated that the peptide is identical with an undecapeptide, substance P, recently isolated from bovine hypothalamus by M.M. Chang and S.E.Leeman. The amount of hypothalamic substance P in bovine dorsal root determined by bioassay or radioimmunoassay was 24-130 pmole/g wet wt, whereas that in the ventral root was 9-27 times less. The effects of synthetic hypothalamic substance P on the isolated spinal cord of the frog and the newborn rat were studied. The peptide exerted a powerful depolarizing action on the motoneurons, its potency being about 200 times higher than that of L-glutamate. Distribution of substance P in the cat spinal cord was studied. The concentration of the peptide was highest in the dorsal part of dy lowered. When the dorsal root of the cat was ligated, substance P accumulated in a high concentration on the ganglion side of the ligature. These results, taken together, support the hypothesis that hypothalamic substance P is an excitatory transmitter of primary afferent neurons.
在牛脊髓神经的背根中发现了一种对蛙脊髓运动神经元具有去极化作用的肽。对这种运动神经元去极化肽的药理、化学和免疫学特性进行了研究，结果表明该肽与一种十一肽——P物质相同，P物质是最近由M.M.张和S.E.利曼从牛下丘脑分离出来的。通过生物测定或放射免疫测定法测定，牛背根中下丘脑P物质的含量为24 - 130皮摩尔/克湿重，而腹根中的含量则少9 - 27倍。研究了合成下丘脑P物质对蛙和新生大鼠离体脊髓的作用。该肽对运动神经元具有强大的去极化作用，其效力约比L - 谷氨酸高200倍。研究了P物质在猫脊髓中的分布。该肽的浓度在背侧部分最高，当猫背根被结扎时，P物质在结扎部位的神经节侧大量积聚。综合这些结果，支持了下丘脑P物质是初级传入神经元兴奋性递质的假说。
