神经递质和调质参与导水管周围灰质痛觉调控的研究进展

导水管周围灰质(periaqueductal gray,PAG)在疼痛的调控过程中处于一个不可或缺的位置.其不仅是痛觉信息上行传递的重要部位,还是疼痛抑制系统的重要组成部分.在PAG,包括γ-氨基丁酸(γ-aminobutyric acid,GABA)、5-羟色胺(5-hydroxytryptamine,5-HT)和谷氨酸(glutamate,Glu)在内的神经递质以及内源性阿片肽(endogenous opioid peptides,EOP)和内源性大麻素(endocannabinoid,e CB)为代表的神经调质都参与了PAG对疼痛的信息传递以及调节.本文重点综述GABA、5-HT、Glu、EOP和eCB在PAG参与疼痛生理调控机制的研究进展,以期为中枢神经系统的镇痛研究提供一定的理论基础.

Neurotransmitters and Modulators of Periaqueductal Gray That Involved in Pain Regulation

Periaqueductal gray(PAG)plays an important role in pain modulation.It is not only an important participant of ascending pain transmission pathways,but also a critical part of descending pain modulation pathways.In PAG,there are evidences that several neurotransmitters(such asγ-aminobutyric acid,5-hydroxytryptamine,glutamate)and neuromodulators(such as endogenous opioid peptide,cannabinoid)are involved in the information transmission and functional regulation of pain.PAG not only regulates pain locally through their own level changes and interaction of these factors,but also regulates pain by receiving fiber projections from other brain regions and sending fiber projections to other pain related brain regions.For example,the analgesic effect of the increased level of GABA in PAG could be realized by the effect of opioid peptides on GABAergic interneurons,or driven directly by the fiber projection from cortex to the GABAergic interneurons in PAG.GABAergic neurons in PAG can also regulate pain by affecting the NAergic fibers projected from A7 cells to the spinal cord.Thus,PAG participates pain modulation in complicated and multiple ways.