Topografia del nucleo spinale del muscolo uretrale: studio sperimentale nel maiale.

The location, number and size of the central motor neurons innervating the urethral muscle (UM) were studied in male pigs, by means of Fast Blue (FB) retrograde transport. After injection of FB into the ventral surface of UM, labelled neurons were found bilaterally in the S1-S3 segments of spinal cord (SC). In these segments the vast majority of labelled neurons were found in a roundish nucleus located in the gray matter laterally in respect to the central canal. The area of these multipolar neurons was ≥ 1000 square micron. A low number of labelled cells were also found in the intermedio-lateral nucleus in an area between the gray and white matter. The area of these multipolar neurons was < 800 square micron.