J Korean Neurosurg Soc.  2007 Dec;42(6):462-469. 10.3340/jkns.2007.42.6.462.

The VR1-Positive Primary Afferent-Mediated Expression of pERK in the Lumbosacral Neurons in Response to Mechanical and Chemical Stimulation of the Urinary Bladder in Rats

• Yoo CJ
• Hwang SJ

• KMID: 2189337
• DOI: http://doi.org/10.3340/jkns.2007.42.6.462

Abstract

OBJECTIVE
This study characterized the neurons in the lumbosacral cord that express phospho ERK (pERK) after distension or irritation of the bladder, and their relation to the vanilloid receptor 1 (VR1) positive primary afferents.
METHODS
Mechanical distension and chemical irritation of the bladder were induced by intravesical injection of the saline and mustard oil, respectively. Spinal neurons expressing pERK and the primary afferent fibers were characterized using multiple immunofluorescence for neurokinin 1 (NK1), neuronal nitric oxide synthetase (nNOS) and VR1.
RESULTS
Neurons in lamina I, medial dorsal horn (MDH), dorsal gray commissure (DGC) and sacral parasympathetic nucleus (SPN) were immunoreactive for pERK after either mechanical or chemical stimulation. The majority of pERK positive cells were positive for NK1 in lamina I and SPN, but not in the DGC. Most of pERK positive cells are not stained for nNOS except in a small population of the cells in the SPN and DGC. Contacts between perikarya and dendrites of pERK-positive cells and terminals of primary afferents expressing VR1 were identified in lamina I, lateral collateral path (LCP) and SPN.
CONCLUSION
In this study, the lumbosacral neurons activated by mechanical and chemical stimulation of the urinary bladder were identified with expression of the pERK, and also provided the evidence that VR1-positive primary afferents may mediate the activation of these neurons.

Keyword

Spinal cord; Visceral sense; Primary afferent; pERK; NK1; VR1

MeSH Terms

Administration, Intravesical
Animals
Dendrites
Fluorescent Antibody Technique
Horns
Mustard Plant
Neurons*
Nitric Oxide Synthase
Rats*
Spinal Cord
Stimulation, Chemical*
Urinary Bladder*
Nitric Oxide Synthase