Tumor necrosis factor-α (TNF-α), otherwise known as a proinflammatory cytokine, turns out to be active on a continual basis in the nervous system. Beattie et al., studied synaptic function in cultured hippocampal neurons and hippocampal brain slices and showed that TNF-α promotes expression of a neurotransmitter receptor on the cell surfaces at synapses. TNF-α is required continuously, suggesting that it may contribute to rapid adjustment of receptor levels at a synapse. TNF-α is supplied by affiliated glial cells, once again reminding us that the glial cells, previously thought to be rather passive support partners, are important behind-the-scenes participants in neuronal function.
E. C. Beattie, D. Stellwagen, W. Morishita, J. C. Bresnahan, B. K. Ha, M.Von Zastrow, M. S. Beattie, R. C. Malenka, Control of synaptic strength by glial TNF-α. Science 295, 2282-2285 (2002). [Abstract] [Full Text]