Motor innervation of the urinary tract studied by retrograde axonal transport of protein.

A new method for tracing the nervous control of the bladder is described. A protein substance, horseradish peroxidase, has been shown to be absorbed and transported by nerve fibers. The substance was injected into the bladder neck region of a series of dogs. After uptake by motor neurons the horseradish was carried to the spinal cord segment controlling micturition. Implications regarding the neurophysiology of the urinary tract are discussed.