Developmental expression of Glutamic Acid Decarboxylase and of γ-Aminobutyric acid type B receptors in the ascidian Ciona intestinalis
Developmental expression of Glutamic Acid Decarboxylase and of γ-Aminobutyric acid type B receptors in the ascidian Ciona intestinalis
复制标题
DOI：
10.1002/cne.21565
复制
发表时间：
2008-01-20
影响因子：
2.5
通讯作者：
Pennati, Roberta
中科院分区：
文献类型：
--
作者：
Zega, Giuliana;Biggiogero, Maira;Pennati, Roberta
我们描述了海鞘γ-氨基丁酸（GABA）能神经元在发育过程中的情况，并通过原位杂交研究了Ci-GAD（谷氨酸脱羧酶：GABA 合成酶）的表达模式。此外，我们克隆了两个 GABA 受体亚基（Ci-GABA(B)Rs），系统发育分析（邻接法）表明它们与脊椎动物对应物聚集在一起。我们比较了 C. Enteris 胚胎和幼虫中的 Ci-GAD 和 Ci-GABABRs 表达模式。在尾芽阶段，Ci-GAD 表达在中枢和周围神经系统 (CNS/PNS) 前体细胞中广泛检测到，而 Ci-GA(B)ARs 表达在内脏神经节前体细胞水平上很明显。通过免疫组织化学将 GABA 定位于同一发育阶段。在幼虫中，在整个 CNS 和 PNS 的一些神经元中也检测到了 Ci-GAD 转录本和 GABA 免疫荧光，而 GABA 受体亚基的转录本主要在 CNS 中发现。 Ci-GABA(B)Rs 的表达模式似乎仅限于感觉囊泡中的 Ci-GAD 阳性区域，而在内脏神经节中，在不表达 Ci-GAD 的腹侧运动神经元中发现了 Ci-GABABRs 转录本。由于 GABA 能神经元也广泛分布在脊椎动物和其他无脊椎动物脊索动物的 CNS 和 PNS 中，因此 GABA 信号传导似乎广泛存在于原索动物神经系统中。这项工作的结果表明，GABA 是肠弯曲杆菌神经系统中最广泛的抑制性神经递质，它可以通过突触前和突触后的 GABA(B) 受体发出信号，以调节不同的感觉输入和随后的游泳活动。
We describe Ciona intestinalis gamma-aminobutyric acid (GABA)-ergic neurons during development, studying the expression pattern of Ci-GAD (glutamic acid decarboxylase: GABA synthesizing enzyme) by in situ hybridization. Moreover, we cloned two GABA, receptor subunits (Ci-GABA(B)Rs), and a phylogenetic analysis (neighbor-joining method) suggested that they clustered with their vertebrate counterparts. We compared Ci-GAD and Ci-GABABRs expression patterns in C. intestinalis embryos and larvae. At the tailbud stage, Ci-GAD expression was widely detected in central and peripheral nervous system (CNS/PNS) precursors, whereas Ci-GA(B)ARs expression was evident at the level of the precursors of the visceral ganglion. GABA was localized by immunohistochemistry at the same developmental stage. In the larva, Ci-GAD transcripts and GABA immunofluorescence were also detected throughout the CNS and in some neurons of the PNS, whereas transcripts of both GABA, receptor subunits were found mainly in the CNS. The expression pattern of Ci-GABA(B)Rs appeared restricted to Ci-GAD-positive territories in the sensory vesicle, whereas, in the visceral ganglion, Ci-GABABRs transcripts were found in ventral motoneurons that did not express Ci-GAD. Insofar as GABAergic neurons are widely distributed also in the CNS and PNS of vertebrates and other invertebrate chordates, it seems likely that GABA signaling was extensively present in the protochordate nervous system. Results from this work show that GABA is the most widespread inhibitory neurotransmitter in C. intestinalis nervous system and that it can signal through GABA(B) receptors both pre- and postsynaptically to modulate different sensory inputs and subsequent swimming activity.