Afferent and efferent branching axons from the rat lumbo-sacral spinal cord project both to the urinary bladder and the urethra as demonstrated by double retrograde neuronal labeling.

A double retrograde axonal tracing technique has been used to ascertain the localization of neuronal cell bodies which give rise to branching axons innervating both the urinary bladder and the urethra in male rat. Application of fluorescent tracers Fast blue (FB) and Diamidino yellow (DY) to postganglionic fibers to the urinary bladder and to the urethra (penile nerve), respectively, produced the double-labeling of neurons located in the dorsal root ganglia and in the 'intermediolateral nucleus'.