Synaptophysin is a synaptic vesicle glycoprotein that is present in neuroendocrine cells and in virtually all neurons in the brain and spinal cord that participate in synaptic transmission. This antibody is a marker for neuroendocrine tumors, and its ubiquity at the synapse has led to the use of synaptophysin immunostaining for quantification of synapses. This antibody reacts with neuroendocrine cells of human adrenal medulla, carotid body, skin, pituitary, thyroid, lung, pancreas and gastrointestinal mucosa; with neurons of the brain, spinal cord, retina, and with Paneth's cells in the gastrointestinal tract and gastric parietal cells. The expression of synaptophysin is independent of the presence of NSE or other neuroendocrine markers; it is an independent broad-range marker of neural and neuroendocrine differentiation.

[1] Kwon SE and Chapman ER (2011) Synaptophysin regulates the kinetics of synaptic vesicle endocytosis in central neurons. Neuron. 70(5):847-54.
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