The blood brain barrier (BBB) evolved to preserve the microenvironment of the highly excitable neuronal cells to allow for action potential generation and propagation. Intricate molecular interactions between two main cell types, the neurons and the glial cells, form the underlying basis of the critical functioning of the nervous system across species. In invertebrates, interactions between neurons and glial cells are central in establishing a functional BBB. However, in vertebrates, the BBB formation and function is coordinated by interactions between neurons, glial cells, and endothelial cells. Here we review the neuron-glial interaction-based blood barriers in invertebrates and vertebrates and provide an evolutionary perspective as to how a glial-barrier system in invertebrates evolved into an endothelial barrier system. We also summarize the clinical relevance of the BBB as this protective barrier becomes disadvantageous in the pharmacological treatment of various neurological disorders.

中文翻译：

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血脑屏障形成中的神经胶质相互作用。

血脑屏障（BBB）进化为保留高度兴奋性神经元细胞的微环境，以允许动作电位的产生和传播。两种主要细胞类型（神经元和神经胶质细胞）之间的复杂分子相互作用，构成了整个物种中神经系统关键功能的基础。在无脊椎动物中，神经元和神经胶质细胞之间的相互作用是建立功能性血脑屏障的关键。然而，在脊椎动物中，神经元，神经胶质细胞和内皮细胞之间的相互作用协调了血脑屏障的形成和功能。在这里，我们回顾了无脊椎动物和脊椎动物中基于神经元-神经胶质相互作用的血屏障，并提供了无脊椎动物的神经胶质屏障系统如何演变为内皮屏障系统的进化观点。