Otsuka M, Konishi S, Yanagisawa M, Tsunoo A, Akagi H
Ciba Found Symp. 1982(91):13-34. doi: 10.1002/9780470720738.ch3.
The hypothesis that substance P (SP) might be a transmitter of primary sensory neurons was first proposed by Lembeck in 1953. A large amount of evidence supporting this hypothesis has recently accumulated, particularly since the elucidation of the chemical structure of SP by Leeman and her colleagues in 1971, which made a number of new approaches possible (e.g. radioimmunoassay for SP, immunohistochemistry and electrophysiological tests of SP action on central and peripheral neurons). SP is concentrated in certain primary afferent terminals in the spinal cord, is released therefrom when the dorsal roots are electrically stimulated, and exerts a powerful excitant action on spinal neurons. It is therefore likely that SP produces excitatory postsynaptic potentials (EPSPs) in spinal neurons, although the characteristics of SP-mediated EPSPs, i.e. their time course, ionic mechanisms, etc., remain to be revealed. Recent electrophysiological and neurochemical studies on the prevertebral ganglia of the guinea-pig strongly suggest that SP is released from axon collaterals of visceral primary afferent neurons in the ganglia and serves as a transmitter that generates non-cholinergic slow EPSPs in principal cells. There is evidence that this SP-mediated synaptic transmission in the sympathetic ganglia is under the influence of enkephalinergic presynaptic inhibition. Some preliminary experiments on the interaction between SP and enkephalins in the spinal cord are described.
1953年，Lembeck首次提出P物质（SP）可能是初级感觉神经元的递质这一假说。最近积累了大量支持这一假说的证据，尤其是自1971年Leeman及其同事阐明SP的化学结构以来，这使得许多新方法成为可能（例如SP的放射免疫测定、免疫组织化学以及SP对中枢和外周神经元作用的电生理测试）。SP集中于脊髓中的某些初级传入终末，当电刺激背根时从那里释放，并对脊髓神经元发挥强大的兴奋作用。因此，SP很可能在脊髓神经元中产生兴奋性突触后电位（EPSP），尽管SP介导的EPSP的特征，即其时程、离子机制等，仍有待揭示。最近对豚鼠椎前神经节的电生理和神经化学研究强烈表明，SP从神经节中内脏初级传入神经元的轴突侧支释放，并作为一种递质在主细胞中产生非胆碱能慢EPSP。有证据表明，交感神经节中这种SP介导的突触传递受脑啡肽能突触前抑制的影响。本文描述了一些关于脊髓中SP与脑啡肽相互作用的初步实验。
