Vasoactive intestinal peptide-immunoreactive nerves in the rat kidney

Area of Science:

• Nephrology
• Neuroscience
• Histology

Background:

• Vasoactive intestinal peptide (VIP) is a neurotransmitter found in various tissues.
• The innervation pattern of VIP-immunoreactive nerves in the kidney is not fully understood.
• Understanding renal innervation is crucial for comprehending kidney function and regulation.

Purpose of the Study:

• To investigate the distribution and density of vasoactive intestinal peptide-immunoreactive (VIPI) nerves within the rat kidney.
• To determine the specific segments of the renal vasculature innervated by VIPI nerves.
• To elucidate the potential roles of VIPI nerves in renal physiology.

Main Methods:

• Indirect immunohistochemistry using an avidin-biotin-horseradish peroxidase complex method.
• Perfusion fixation of rat kidneys with paraformaldehyde or picric acid solutions.
• Vibratome sectioning and incubation with primary antiserum for VIPI nerves.

Main Results:

• A sparse plexus of VIPI nerves was observed in the rat renal calyx.
• VIPI nerves were found to innervate interlobar arteries and subsequent arterial segments, including afferent arterioles.
• The majority of VIPI nerves innervated arcuate and interlobular arteries, with a non-uniform density along these vessels.

Conclusions:

• Most VIPI nerves in the rat kidney innervate restricted segments of the renal arterial tree, particularly arcuate and interlobular arteries.
• These VIPI nerves may function as efferent nerves, potentially regulating the dilation of arcuate and smaller arteries.
• Alternatively, VIPI nerves could act as afferent nerves, sensing local mechanical or chemical parameters within the kidney.