Wolff J R, Joó F, Kása P
Department of Anatomy, University of Göttingen, Federal Republic of Germany.
Neurochem Res. 1993 Apr;18(4):453-61. doi: 10.1007/BF00967249.
Apart from being a prominent (inhibitory) neurotransmitter that is widely distributed in the central and peripheral nervous system, gamma-aminobutyric acid (GABA) has turned out to exert trophic actions. In this manner GABA may modulate the neuroplastic capacity of neurons and neuron-like cells under various conditions in situ and in vitro. In the superior cervical ganglion (SCG) of adult rat, GABA induces the formation of free postsynaptic-like densities on the dendrites of principal neurons and enables implanted foreign (cholinergic) nerves to establish functional synaptic contacts, even while preexisting connections of the preganglionic axons persist. Apart from postsynaptic effects, GABA inhibits acetylcholine release from preganglionic nerve terminals and changes, at least transiently, the neurochemical markers of cholinergic innervation (acetylcholinesterase and nicotinic receptors). In murine neuroblastoma cells in vitro, GABA induces electron microscopic changes, which are similar in principle to those seen in the SCG. Both neuroplastic effects of GABA, in situ and in vitro, could be mimicked by sodium bromide, a hyperpolarizing agent. In addition, evidence is available that GABA via A- and/or B-receptors may exert direct trophic actions. The regulation of both types of trophic actions (direct, receptor-mediated vs. indirect, bioelectric activity dependent) is discussed.
γ-氨基丁酸（GABA）不仅是一种广泛分布于中枢和外周神经系统的重要（抑制性）神经递质，还具有营养作用。通过这种方式，GABA可以在原位和体外的各种条件下调节神经元和类神经元细胞的神经可塑性。在成年大鼠的颈上神经节（SCG）中，GABA可诱导主神经元树突上形成游离的突触后样致密物，并使植入的外来（胆碱能）神经建立功能性突触联系，即使节前轴突的原有连接仍然存在。除了突触后效应外，GABA还抑制节前神经末梢释放乙酰胆碱，并至少短暂地改变胆碱能神经支配的神经化学标志物（乙酰胆碱酯酶和烟碱受体）。在体外培养的小鼠神经母细胞瘤细胞中，GABA可诱导电子显微镜下的变化，这些变化原则上与在SCG中观察到的变化相似。GABA在原位和体外的两种神经可塑性效应都可以被超极化剂溴化钠模拟。此外，有证据表明GABA通过A和/或B受体可能发挥直接的营养作用。本文讨论了这两种营养作用类型（直接的、受体介导的与间接的、生物电活动依赖性的）的调节。
