Clatworthy A L
Department of Integrative Biology and Pharmacology, University of Texas, Houston Medical School, Houston, Tex., USA.
Neuroimmunomodulation. 1998 May-Aug;5(3-4):136-42. doi: 10.1159/000026330.
Efforts to understand how the immune system can influence nervous system function are hampered by the complexity of mammalian nervous and immune systems. The marine mollusc Aplysia californica has recently emerged as a useful model system to investigate cellular mechanisms underlying neural-immune interactions. Aplysia has a relatively simple, well-characterized nervous system that is accessible for intracellular recording. Moreover, it shares with mammals basic cellular defensive responses to non-self or wounded-self, i.e. the accumulation of numerous defense cells (hemocytes) around foreign objects or at injured sites. We have shown that the excitability of a population of nociceptive sensory neurons in Aplysia can be influenced by the presence of hemocytes close to their axons. These sensory neurons also show profound, long-lasting increases in their excitability following axonal injury. Hemocytes are attracted to injured sites on peripheral nerves, and we have developed an in vitro nervous system-hemocyte coculture system to demonstrate that hemocytes can also influence the expression of this injury-induced sensory hyperexcitability. Immunoreactive interleukin-1 (IL-1) and tumor necrosis factor have been identified in Aplysia. Preliminary in vitro studies showing that IL-1 can modulate the expression of injury-induced sensory hyperexcitability raise the interesting possibility that hemocyte-derived cytokine-like factors can modulate sensory neuron functioning. The relevance of this work to more phylogenetically advanced organisms is also discussed.
由于哺乳动物神经和免疫系统的复杂性，理解免疫系统如何影响神经系统功能的研究受到了阻碍。海生软体动物加州海兔最近成为研究神经 - 免疫相互作用潜在细胞机制的有用模型系统。海兔拥有相对简单且特征明确的神经系统，便于进行细胞内记录。此外，它与哺乳动物一样，对非自身或受伤自身具有基本的细胞防御反应，即在外来物体周围或受伤部位积累大量防御细胞（血细胞）。我们已经表明，海兔中一群伤害性感觉神经元的兴奋性会受到靠近其轴突的血细胞的影响。这些感觉神经元在轴突损伤后其兴奋性也会出现深刻而持久的增加。血细胞被吸引到外周神经的损伤部位，我们开发了一种体外神经系统 - 血细胞共培养系统，以证明血细胞也能影响这种损伤诱导的感觉超兴奋性的表达。在海兔中已鉴定出免疫反应性白细胞介素 -1（IL -1）和肿瘤坏死因子。初步的体外研究表明，IL -1可以调节损伤诱导的感觉超兴奋性的表达，这引发了一个有趣的可能性，即血细胞衍生的细胞因子样因子可以调节感觉神经元的功能。本文还讨论了这项工作与进化上更高级生物的相关性。
