Genitourinary Functions Research Articles

Fascicular anatomy and surgical access of the human pudendal nerve

The ability to access selectively distal nerve branches at the level of the compound pudendal nerve (PN) would allow control of multiple neural pathways and genitourinary functions at a single location. Nerve cuff electrodes can selectively stimulate individual fascicles; however the PN fascicular anatomy is unknown. The fascicular representation of distal branches was identified and traced proximally to create fascicle maps of 12 compound PNs in seven cadavers. Distal nerves were represented as groups of individual fascicles in the PN. Fascicle maps were consistent between specimens and along the PN within specimens. PN branch free length was 26+/-7.7 mm. PN cross-sections were relatively flat with major and minor diameters of 4.3+/-0.90 and 1.7+/-0.45 mm, respectively. Placing a nerve cuff on the PN is anatomically and surgically feasible. The PN fascicular anatomy, branch free length, and cross-section geometry are conducive to selective stimulation of distal nerves with a single nerve cuff electrode.

Koro: A state of sexual panic or altered physiology?

Abstract ‘Koro&’ is a syndrome clinically characterized by an acute panic reaction about genital retraction and fear of impending death. It has been regarded as a purely psychogenic illness, initiated by cultural sexual myths and beliefs. Recent global reportings of Koro from diverse ethno-cultural contexts, however, support the role of physical factors in vulnerable individuals. These include penile changes as a result of vasoconstriction from exposure to cold, fright or genito-urinary functions. An updated analysis of world Koro literature confirms this.

Nitric oxide control of lower genitourinary tract functions: A review

It is apparent that evolving concepts of the regulatory basis for functions in the pelvis must take into account the role exerted by nitric oxide. A recently characterized messenger molecule, nitric oxide has been associated with numerous physiologic processes. Intense investigations of this molecule have extended its importance to several genitourinary functions. Penile erection, micturition, peristalsis of the male excurrent duct system, contractile properties of the prostate, and lumbosacral spinal cord neurotransmission are all functions that may transpire under some degree of control by nitric oxide. Impotence, urinary obstruction, or ejaculatory problems, in turn, may represent alterations of nitric oxide production or action. The strategic manipulation of nitric oxide or its mechanism of action, possibly by pharmacologic means, may restore or produce desired functional effects. These possibilities, therefore, suggest that the advancing knowledge of nitric oxide in the genitourinary tract may be of enormous clinical value in the future.

Nitric Oxide – A Novel Autonomic Neurotransmitter

Considerable evidence suggests that nitric oxide (NO) acts as a nonadrenergic noncholinergic (NANC) transmitter at autonomic neuroeffector junctions. NO is generated enzymatically from L-arginine by a constitutive, cytosolic, Ca2+/calmodulin-activated NO synthase (NOS): NADPH- and tetrahydrobiopterin-dependent cytochrome P-450-type hemoprotein. Electrophysiological and pharmacological data indicate that NO fulfils most of the criteria for a neurotransmitter. It is released from axon terminals when invaded by action potentials and mimics the effect of nerve stimulation. The changes in the mechanical and/or electrical activity of smooth muscle preparations in response to transmural stimulation of NANC nerves are antagonized by inhibitors of NO synthesis or oxyhemoglobin, an NO scavenger. NO acts principally by stimulating soluble guanylate cyclase. Studies on the histochemical localization of NOS point to the involvement of the neural L-arginine-NO pathway in the regulation of vascular tone and of several aspects of respiratory, gastrointestinal, and genitourinary tract functions.