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A review has been made on the role of nitric oxide in the physiology and pathophysiology of penis, bladder, prostate and the nervous structures involved in the urinary control. NO is an essential mediator in penile erection and his action can be modulated by sildenafil. Nitric oxide could be involved in bladder detrusor relaxation and in the development of interstitial cystitis. Little is known about the role of nitric oxide in the physiology and pathophysiology of the prostate: this molecule is released by the epithelial and stromal cells of the prostate, and by the prostatic nerves. Actually some studies hypothesize a role played by nitric oxide in benign prostatic hyperplasia development.

During the last decade, the cellular pathways involved in excitation-contraction coupling have been identified and explained. The key event in the initiation of the contraction is the rise in sarcoplasmic free calcium. Inositol 1,4,5-triphosphate (IP3) and cyclic nucleotides (cAMP, cGMP) have been demonstrated to be the second messengers associated with stimulation of smooth muscle selective receptor-subtypes (cholinergic, adrenergic, non adrenergic-non cholinergic) by specific neuromodulators. Furthermore, activation of voltage-gated L type- or receptor operated calcium channels is involved in the sarcoplasmic free calcium changes. KCa and KATP-channels play an important role in smooth muscle hyperpolarization; KATP-openers excite great interest as therapeutic agents for the detrusor instability. The specificity of different receptor subtypes and their transductional pathways has increased the number of targets for drug treatment of urinary bladder disorders and erectile dysfunction. As the level of intracellular nucleotide second messengers can be modulated by tissue-specific phosphodiesterase (PDE) isoenzymes, PDEs selective inhibitors have the potential to exert organ-specific therapeutic effects. So, PDE I selective inhibitor vinpocetine has been proposed for the symptomatic treatment of detrusor instability; PDE V selective inhibitor sildenafil, enhancing the NO-cGMP pathway-mediated cavernosal smooth muscle relaxation, is an effective drug to treat erectile dysfunction.

A case of surgical reconstruction after penoscrotal skin avulsion is described. Penile coverage was gained by two full thickness grafts helicoidally placed to avoid retractions. Scrotal reconstruction was carried out in two steps, after testis subcutaneous implantation, with axial flaps expanded in abdominal region. The procedure has the advantage of flaps sure vitality, avoids patient discomfort produced by a perineal expansion with satisfactory cosmetic appearance and restore of a normal sexual function.

The Wistar rat represents a very useful model in experimental surgery and in scientific research. The anatomic structures are very similar to those encountered in man. Moreover the cost for their purchase, breeding and nourishment is very low and it's possible to perform surgical maneuvers without sterility. Nevertheless the penis has an extremely small dimension and its anatomic structure is quite different from that of man because corpora cavernosa are almost completely occupied by an osteo-cartilagenous formation: the os penis. For this reason it's very difficult to perform a physiopathological study of erection on the rat. On the other hand the nervous fibres are very similar for course and localization to those encountered in man and monkeys. Their electrical stimulation causes an erection which is adequate in duration and intensity to be evident.