Login to Access Video or Poster Abstract: MP42-16
Sources of Funding: NIH-NINDS NS070267

Introduction

Many studies focus on afferent or efferent inputs (but not both), or on one structure of the genitourinary system. Only a few studies include information on inputs from sympathetic chain ganglia (SCG), and even fewer have examined the possibility of direct motor (autonomic or somatic) inputs from spinal cord ventral horns to genitourinary end organs. We sought to clarify origins of afferent and efferent information conveyed between the spinal cord, peripheral nervous system ganglia and genitourinary structures using retrograde and anterograde neurotracing dyes.

Methods

Dyes were injected into the bladder wall, external urethral sphincter (EUS) and clitoris of 14 female mongrel dogs (Fluorogold, True blue, or Nuclear Yellow). Dorsal root ganglia (DRG), SCG, caudal mesenteric ganglion (CMG), pelvic plexus ganglia and spinal cord ventral horns were examined for dye-labeled neuronal cell bodies. Detrusor muscle intramural ganglia were examined by injecting DiI into the pelvic nerve’s anterior vesicle branch.

Results

Retrograde labeled cells were observed in several DRGs, representative of afferent input from the bladder, EUS and clitoris (Table). Anterograde labeling revealed intramural ganglia in the bladder wall. Sympathetic efferents included: 1) labeled cells in the CMG primarily from the bladder, yet small numbers from the EUS and clitoris; 2) labeled cells in SCG primarily from the bladder (widespread) and more localized input from EUS and clitoris (Table); and 3) labeled cells in the intermediolateral cell column of thoracolumbar cord segments directly to the bladder and clitoris, a locale typically considered as sympathetic. Parasympathetic efferents included: 1) labeled neurons in pelvic plexus ganglia in bladder mesenteries; and 2) cells in lamina VII of sacral cord segments directly to the bladder and clitoris, a locale typically considered as sympathetic. Lastly, somatic (skeletal muscle) efferents to the EUS were evident as retrogradely labeled cells in sacral lamina IX cells.

Conclusions

Afferent and efferent inputs to genitourinary structures are complex, yet a clear knowledge is needed to understand dysfunction after spinal cord injury and mechanisms underlying chronic pain syndromes in this region.

Funding

NIH-NINDS NS070267