Neuro-immune connections: evidence for a neuro-immunological synapse

To emphasize the functional and molecular interconnections of the immune and nervous systems, we propose the use of a new term, 'neuro-immunological (NI) synapse', to describe specialized contact zones between adrenergic neurons and lymphocytes or antigen-presenting cells (APCs). Based on electron microscopic observations, Felten et al. were among the first to show that noradrenergic neurons tightly contact lymphocytes and APCs of the peri-arteriolar lymphoid sheath of the spleen [ 1 Felten D.L. et al. Noradrenergic sympathic neural interactions with the immune system: structure and function. Immunol. Rev. 1987; 100: 225-260 Crossref PubMed Scopus (684) Google Scholar ]. In addition, they demonstrated 'synaptic-type' specialization, such as thickening of pre-synaptic cellular membranes and concentration of vesicles containing neurotransmitters at neuron–immune-cell junctions.