Long S K, Evans R H, Krijzer F
Duphar B.V. Weesp, Holland.
Neuropharmacology. 1989 Jul;28(7):683-8. doi: 10.1016/0028-3908(89)90151-2.
A mature sacrococcygeal in vitro spinal preparation from the rat has been used to demonstrate effects of neutral amino acids and their antagonists. gamma-Aminobutanoate (GABA), glycine and taurine (0.5-5 mM) produced dose-dependent depression of spontaneous paroxysmal activity generated in Mg2+ -free medium. The depressant effect of GABA was antagonised selectively by picrotoxin (25-50 microM) and the depressant effects of glycine and taurine were antagonised selectively by strychnine (0.2 microM). Glycine (0.5-5 mM) had a dose-dependent depolarizing action which was present at the central ends of isolated ventral roots. gamma-Aminobutanoate and taurine, had only weak depolarizing actions on ventral root fibres. Depolarizing responses to glycine showed a marked fading. Reduction in the fading appeared to be responsible for a paradoxical potentiation of glycine-induced depolarizations, which occurred in the presence of strychnine (0.2-2 microM). Strychnine (2-10 microM), picrotoxin (10-50 microM) or bicuculline (10 microM) had little or no effect on the amplitude, duration or latency of the monosynaptic component of ventral root reflexes evoked by supramaximal stimulation of dorsal roots (DR-VRP). However all three antagonists introduced slow, NMDA receptor mediated, components to these ventral root potentials. Picrotoxin and bicuculline, but not strychnine, reversibly depressed the dorsal root potential evoked from an adjacent dorsal root (DR-DRP). The depressant actions of 2-amino-5-phosphonopentanoate (AP5), kynurenate and 3-((+/-)-2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP) revealed both NMDA and non-NMDA receptor mediated components in the dorsal root potential.
已使用来自大鼠的成熟骶尾体外脊髓制剂来证明中性氨基酸及其拮抗剂的作用。γ-氨基丁酸（GABA）、甘氨酸和牛磺酸（0.5 - 5 mM）在无镁培养基中产生的自发性阵发性活动呈现剂量依赖性抑制。GABA的抑制作用被苦味毒（25 - 50 μM）选择性拮抗，甘氨酸和牛磺酸的抑制作用被士的宁（0.2 μM）选择性拮抗。甘氨酸（0.5 - 5 mM）具有剂量依赖性的去极化作用，该作用存在于分离的腹根中枢端。γ-氨基丁酸和牛磺酸对腹根纤维只有微弱的去极化作用。对甘氨酸的去极化反应表现出明显的衰减。衰减的减少似乎是甘氨酸诱导的去极化出现反常增强的原因，这种增强发生在存在士的宁（0.2 - 2 μM）的情况下。士的宁（2 - 10 μM）、苦味毒（10 - 50 μM）或荷包牡丹碱（10 μM）对背根最大刺激诱发的腹根反射单突触成分的幅度、持续时间或潜伏期几乎没有影响（DR - VRP）。然而，所有这三种拮抗剂都给这些腹根电位引入了缓慢的、NMDA受体介导的成分。苦味毒和荷包牡丹碱，但不是士的宁，可逆地抑制从相邻背根诱发的背根电位（DR - DRP）。2 - 氨基 - 5 - 膦酰戊酸（AP5）、犬尿烯酸和3 - （（±） - 2 - 羧基哌嗪 - 4 - 基）丙基 - 1 - 膦酸（CPP）的抑制作用揭示了背根电位中NMDA和非NMDA受体介导的成分。
