Nerves and perisinusoidal cells in human liver.

Unmyelinated nerve fibres are visible in the human hepatic lobule. They extend through the Disse space, surrounded by Schwann cell processes, often close to perisinusoidal cell processes. A few bare nerve endings or varicosities are found contiguous to either hepatocytes or perisinusoidal cells. These nerve endings or varicosities contain large and small granular vesicles and small clear vesicles. This heterogeneity probably corresponds to the presence of various neurotransmitters (noradrenaline, acetylcholine, various neuropeptides...). The effect of nerves on perisinusoidal cells has not yet been elucidated. However, the location, shape, morphology and origin of perisinusoidal cells would suggest that they play a role in the hemodynamic regulation of sinusoidal blood flow. It has recently been shown how important non-parenchymal-parenchymal communication is in the action of nerves on glucose release by hepatocytes; the cell to cell communications may also apply to nerves and sinusoidal cells for the hemodynamic regulation of sinusoidal blood flow.