Neurogenic erectile dysfunction: the course of nicotinamide adenine dinucleotide phosphate diaphorase-positive nerve fibers on the surface of the prostate

OBJECTIVES: Nitric oxide (NO) plays an important role as a neurotransmitter in the peripheral neural regulation of erection. A histochemical stain able to localize fibers releasing NO in combination with an in vivo study were used to evaluate the course and physiologic significance of the nerve fibers innervating the cavernous smooth muscle.

METHODS: Morphologic studies in 6 rats and 6 human cadavers were performed, tracing the course of branches of the cavernous nerve branches using a nicotinamide adenine dinucleotide phosphate diaphorase staining technique. Electrostimulations in rats were performed before and after transection of the anterolateral part of the prostate capsule.

RESULTS: Multiple nerve fibers were documented running on the lateral and ventral surfaces of the prostate distinct from the classically described dorsolateral neurovascular bundle. Transection of these fibers resulted in a loss of electrically induced intracavernous pressure (59.4 +/- 5.6 cm H2O versus 27.0 +/- 4.6 cm H2O).

CONCLUSIONS: These preliminary morphologic and physiologic studies support a significant role for these nerve fibers in erection.