Diabetes Research Institute, Miller School of Medicine, University of Miami, Miami, FL 33136, USA.
Cell Metab. 2011 Jul 6;14(1):45-54. doi: 10.1016/j.cmet.2011.05.008.
The autonomic nervous system regulates hormone secretion from the endocrine pancreas, the islets of Langerhans, thus impacting glucose metabolism. The parasympathetic and sympathetic nerves innervate the pancreatic islet, but the precise innervation patterns are unknown, particularly in human. Here we demonstrate that the innervation of human islets is different from that of mouse islets and does not conform to existing models of autonomic control of islet function. By visualizing axons in three dimensions and quantifying axonal densities and contacts within pancreatic islets, we found that, unlike mouse endocrine cells, human endocrine cells are sparsely contacted by autonomic axons. Few parasympathetic cholinergic axons penetrate the human islet, and the invading sympathetic fibers preferentially innervate smooth muscle cells of blood vessels located within the islet. Thus, rather than modulating endocrine cell function directly, sympathetic nerves may regulate hormone secretion in human islets by controlling local blood flow or by acting on islet regions located downstream.
自主神经系统调节内分泌胰腺（胰岛）的激素分泌，从而影响葡萄糖代谢。副交感神经和交感神经支配胰岛，但确切的支配模式尚不清楚，特别是在人类中。在这里，我们证明人类胰岛的神经支配与小鼠胰岛不同，不符合现有胰岛功能自主控制的模型。通过在三维空间中可视化轴突并定量分析胰岛内轴突的密度和接触，我们发现与小鼠内分泌细胞不同，人类内分泌细胞与自主神经轴突的接触很少。很少有副交感胆碱能轴突穿透人类胰岛，而入侵的交感纤维优先支配位于胰岛内的血管平滑肌细胞。因此，交感神经可能不是通过直接调节内分泌细胞功能，而是通过控制局部血流或作用于胰岛下游区域来调节人类胰岛中的激素分泌。
