Neuropeptide Y (NPY)-like immunoreactive nerve fibers in the human and monkey (Macaca fascicularis) kidney

Nerve fibers immunoreactive for neuropeptide Y (NPY) are demonstrated for the first time by the indirect immunofluorescence technique in the human and monkey kidney. NPY-like immunoactivity (NPY-LI) is shown in a bundle of nerve fibers in the surrounding connective tissue of arteries and to a lesser extent, veins, mainly at the juxtamedullary region. Varicose nerve terminals are shown associated with blood vessels and passing between tubules in the mid and lower cortex. NPY-LI nerve fibers are also seen surrounding afferent and occasionally efferent arterioles at the vascular pole of the glomeruli. The distribution of NPY-LI nerve fibers in the monkey and human kidneys is similar to that of other species, only the quantity of the nerve fibers varies.