The neurotransmitter gamma-aminobutyric acid (GABA) is widely distributed in the mammalian central nervous system, where it acts as a major mediator of synaptic inhibition. GABA also serves as a neurotransmitter in a range of invertebrate phyla, including arthropods, echinoderms, annelids, nematodes, and platyhelminthes. This article reviews evidence supporting the neurotransmitter role of GABA in gastropod molluscs, with an emphasis on its presence in identified neurons and well-characterized neural circuits. The collective findings indicate that GABAergic signaling participates in the selection and specification of motor programs, as well as the bilateral coordination of motor circuits. While relatively few in number, GABAergic neurons can influence neural circuits via inhibitory, excitatory, and modulatory synaptic actions. GABA’s colocalization with peptidergic and classical neurotransmitters can broaden its integrative capacity. The functional properties of GABAergic neurons in simpler gastropod systems may provide insight into the role of this neurotransmitter phenotype in more complex brains.

中文翻译：

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GABA 作为腹足类软体动物的神经递质

神经递质 γ-氨基丁酸 (GABA) 广泛分布于哺乳动物的中枢神经系统中，是突触抑制的主要介质。GABA 还在一系列无脊椎动物门中充当神经递质，包括节肢动物、棘皮动物、环节动物、线虫和扁形动物。本文回顾了支持 GABA 在腹足动物软体动物中的神经递质作用的证据，重点是它存在于已识别的神经元和充分表征的神经回路中。集体发现表明 GABA 能信号参与运动程序的选择和规范，以及运动电路的双边协调。虽然数量相对较少，但 GABA 能神经元可以通过抑制性、兴奋性和调节性突触作用影响神经回路。GABA 与肽能和经典神经递质的共定位可以扩大其整合能力。GABA 能神经元在较简单的腹足动物系统中的功能特性可能有助于深入了解这种神经递质表型在更复杂的大脑中的作用。