The renal afferent pathways in the rat: a pseudorabies virus study

Area of Science:

• Neuroscience
• Renal Physiology
• Autonomic Nervous System

Background:

• Previous studies identified renal innervation from dorsal root ganglion cells (T8-L2) and sympathetic afferents in the thoracic/lumbar dorsal horn.
• The precise pathways for renal sensory information remain incompletely understood.

Purpose of the Study:

• To investigate the spread of pseudorabies virus (PRV) through renal sensory pathways in rats.
• To identify and map sympathetic and parasympathetic afferent pathways innervating the kidney.
• To determine potential convergence sites for renal sensory information.

Main Methods:

• Renal inoculation of PRV in rats, followed by immunocytochemical localization of the virus at 2-5 days post-infection (PI).
• Analysis of infected dorsal root ganglion (DRG) neurons and spinal cord dorsal horn labeling.
• Assessment of viral spread after renal denervation and dorsal root sectioning.

Main Results:

• PRV infected DRG neurons (first-order sympathetic afferents) within 2 days PI, with contralateral labeling observed.
• Infected neurons were found in the dorsal horn (laminae I-II) and nodose ganglia (suggesting parasympathetic involvement) by 4 days PI.
• Viral labeling extended to the nucleus tractus solitarius (NTS) by 5 days PI, with renal denervation and dorsal root sectioning blocking central spread.

Conclusions:

• PRV infection effectively identifies renal afferent pathways, including both sympathetic and parasympathetic components.
• Renal afferent information appears to travel via both sympathetic and parasympathetic nerves.
• Sensory information from the kidney may converge at the nucleus tractus solitarius.