Niel J P
Département de Physiologie et Neurophysiologie U.R.A. C.N.R.S. 205 Faculté des Sciences et Techniques St Jérome, Marseille.
Arch Int Physiol Biochim Biophys. 1991 Sep;99(5):A65-76. doi: 10.3109/13813459109145918.
Substance P is a 11 amino-acids peptide which belongs to the tachykinins, a family of peptide which induces a rapid contraction of the smooth muscle of the digestive tract. The occurrence of substance P has been demonstrated by immunohistochemical and radioimmunological techniques in most parts of the central and peripheral nervous system. Substance P exerts on the smooth muscle of all the areas of the digestive tract a strong excitatory effect which is either direct or relayed by the cholinergic intramural neurones. Numerous electrophysiological, pharmacological and immunohistochemical data lead to the conclusion that substance P is released by intrinsic neurones of the digestive tract or by extrinsic nerves (vagus and splanchnic nerves, etc...). This release is enhanced by acetylcholine, cholecystokinin, serotonin and neurotensin, it is reduced by opioid peptides and noradrenaline. Substance P participates in the intestinal peristaltic reflex by the activation of the smooth muscle cells of the intestine, either directly or through the activation of the cholinergic intrinsic neurones. Substance P is also involved in the genesis of a non-cholinergic ascending excitatory activity likely occurring during vomiting. Lastly, substance P participates in the reflex contraction of the lower oesophageal sphincter following acidification of the distal part of the oesophagus.
P物质是一种由11个氨基酸组成的肽，属于速激肽家族，该家族肽可引起消化道平滑肌快速收缩。通过免疫组织化学和放射免疫技术已证实在中枢和外周神经系统的大部分区域均存在P物质。P物质对消化道所有区域的平滑肌均有强烈的兴奋作用，这种作用可以是直接的，也可以通过胆碱能壁内神经元介导。大量的电生理、药理学和免疫组织化学数据表明，P物质由消化道的内在神经元或外在神经（迷走神经和内脏神经等）释放。乙酰胆碱、胆囊收缩素、5-羟色胺和神经降压素可增强这种释放，阿片肽和去甲肾上腺素则使其减少。P物质通过直接激活肠平滑肌细胞或通过激活胆碱能内在神经元参与肠道蠕动反射。P物质还可能参与呕吐过程中可能出现的非胆碱能性上行兴奋活动的发生。最后，P物质参与食管远端酸化后下食管括约肌的反射性收缩。
