大鼠三叉神经脊束核尾侧亚核浅层内谷氨酸能、γ-氨基丁酸能和甘氨酸能终末的中枢起源

三叉神经脊束核尾侧亚核浅层（I、II层）内有较密集的谷氨酸样、γ-氨基丁酸样和甘氨酸样阳性终未。这些终未除分别来自外周初级传入或局部神经元外，还可能来自脑干的核团。为了探讨这些阳性终未的脑干起源部位，本研究用荧光金逆行追踪与免疫荧光组织化学染色相结合的双标技术对三叉尾侧亚核浅层内谷氨酸能、γ-氨基丁酸能和甘氨酸能终未在脑干的起源部位进行了追踪。结果表明：大鼠脑干向三叉尾侧亚核发出谷氨酸能、γ-氨基丁酸能和甘氨酸能投射的神经元主要位于构成下行抑制系统的中脑中央灰质、中缝大核及其周围的网状结构、中缝苍白核和中缝隐核。本研究的结果提示，除已知的5-羟色胺和P物质外，谷氨酸、γ-氨基丁酸和甘氨酸也可能参与下行抑制系统，对面口部伤害性刺激信息传递发挥调控作用。

CENTRAL ORIGINS OF THE GLUTAMATE-, GABA-AND GLYCINE-LIKE IMMUNOREACTIVE TERMINALS IN THE SUPERFICIAL LAMINAE OF CAUDAL SPINAL TRIGEMINAL NUCLEUS IN THE RAT

Glutamate (Gin)-, γ-aminobutyric acid (GABA)- and glycine (Gly)-like immunoreactive terminals were densely observed in the superficial laminae of the caudal spinal trigeminal nucleus (Vc). Except for originating from primary afferents and local neurons of the Vc, respectively. these terminals might also come from nuclei of the brainstem. Employing a combination of Fluoro-Gold (FG ) retrograde tracing with imnlunofluorescence histochenlical staining for phosphate activated glutaminase (PAG, a key enzyme for the Glu sythese in the centlal nervous system), GABA and Gly. we investigated the central origins of the PAG-, GABA- and Gly-like immunoreactive terminals in the caudal spinal trigeminal nucleus(Vc) in the rat. The neurons which send their glutamatergic. GABAergic and glycinergic axons from brainstem to the Vc were mainly distributed within the areas of midbrain central gray, nucleus raphe magnus and their adjacent reticular formation, nucleus raphe pallidus. nucleus raphe obscurus, which constitute the descending inhibitory system. The results indicate that besides the pulative neuronal active substances of serotonin and substance P, Glu, GABA and Gly might be the candidates of neurotransmitter and/or neuronlodulators which also play important roles in modulating the process of nociceptive information transmission from orofacial region.