Nicholson G M, Spence I, Johnston G A
Neuropharmacology. 1985 Jun;24(6):465-71. doi: 10.1016/0028-3908(85)90050-4.
The effect of 5-(2-cyclohexylideneethyl)-5-ethyl barbituric acid (CHEB) on the isolated spinal cord of the immature rat was examined using extracellular recording. At concentrations less than 20 microM CHEB increased the monosynaptic reflex (MSR) but depressed the reflex at greater concentrations (30-100 microM). At concentrations which enhanced the monosynaptic reflex, CHEB reduced the responses of motoneurones to glycine and to a lesser extent to those of L-glutamate. In the presence of strychnine (5 microM), which enhanced both mono- and polysynaptic reflexes, CHEB produced only slight enhancement of the monosynaptic reflex. At concentrations of 30-100 microM the responses to gamma-aminobutyric acid (GABA), glycine, L-glutamate and eledoisin-related peptide (ERP a substance P and analogue) were all reduced. At these concentrations CHEB directly depolarised the motoneurone membrane. Increases in [Mg2+]0, which reduced spontaneous activity, blocked the enhancement, by CHEB, of the monosynaptic reflex. The actions of CHEB in small doses may be due therefore to its ability to block the action of glycine and thus block tonic inhibition.
采用细胞外记录法研究了5-(2-环己叉乙基)-5-乙基巴比妥酸（CHEB）对未成熟大鼠离体脊髓的作用。浓度低于20微摩尔时，CHEB增强单突触反射（MSR），但浓度更高（30 - 100微摩尔）时则抑制该反射。在增强单突触反射的浓度下，CHEB降低运动神经元对甘氨酸的反应，并在较小程度上降低对L-谷氨酸的反应。在增强单突触和多突触反射的士的宁（5微摩尔）存在时，CHEB仅轻微增强单突触反射。在30 - 100微摩尔浓度下，对γ-氨基丁酸（GABA）、甘氨酸、L-谷氨酸和eledoisin相关肽（ERP，一种P物质及其类似物）的反应均降低。在这些浓度下，CHEB使运动神经元膜直接去极化。细胞外液中镁离子浓度（[Mg2+]0）升高会降低自发活动，并阻断CHEB对单突触反射的增强作用。因此，小剂量CHEB的作用可能是由于其阻断甘氨酸作用从而阻断紧张性抑制的能力。
