ABSTRACT
Purpose: No ideal method for subdividing and assessing changes in neurons of the spinal cord during specific conditions has been established. We attempted to develop a method for subdividing spinal neurons using immunohistochemical and fluorescent staining, which is an important key towards understanding the mechanism of reflex voiding. Materials and Methods: Thirty Sprague-Dawley rats, weighting 200-300g, were divided into five groups. A cystometrogram was performed during saline or acetic acid instillation. We identified the neuronal pathway associated with the detrusor by injecting a pseudorabies virus (PRV) into the detrusor muscle and inspecting the changes in relation to different time sequences. An immunohistochemical staining method was used to stain the fos-protein encoded by the c-fos gene. Immunofluorescent staining was performed to evaluate changes in the neurons in relation to the voiding reflex, and the neurons then subdivided. Results: We confirmed pseudorabies virus (PRV) infection of the cells in the sacral parasympathetic nucleus through immunohistochemical staining two days after injection. On detection of an increase in c-fos positive cells after dividing the c-fos positive area of the L6 and S1 spinal cord into 4 sections, significant increases were observed in the sacral parasympathetic nucleus (SPN) and dorsal commissure (DCM). Double staining was performed to detect the neurons associated with the voiding reflex in the SPN and DCM areas showing overexpression of c-fos. Conclusions: The establishment of a method for detecting morphological changes, and subdividing neurons by immunohistochemical and fluorescent staining, may provide an important key towards understanding the mechanism of various neuromodulations of clinically applied treatments. (Korean J Urol 2005;46:487-494)