The neuromorphology and neuropharmacology of the human penis are only briefly described in literature. The present study was undertaken to define the adrenergic and cholinergic neuromorphology of the human corpus cavernosum (CC) and corpus spongiosum and to evaluate the in vitro response of the CC to pharmacologic stimulation. Human penile tissue was obtained from six transsexual patients undergoing penectomy. For morphologic study, the tissue was processed for (a) hematoxylin and eosin staining; (b) smooth muscle staining; (c) acetylcholinesterase localization; (d) glyoxylic acid histofluorescence; (e) electron microscopy; and (f) electron microscopy after glutaraldehyde dichromate fixation. In addition, strips of CC were placed in in vitro muscle chambers and tension changes recorded isometrically after stimulation with norepinephrine (NE) and acetylcholine. The CC contains abundant smooth muscle, numerous glyoxylic acidfluorescent (catecholaminergic) fibers and varicosities, and a scant distribution of acetylcholinesterase-positive fibers. Fewer of all these elements were present in the corpus spongiosum. No “polsters” were observed in the CC. Although glutaraldehyde-fixed controls exhibited no typical adrenergic vesicles (small, dense core, measuring 400-600 Å in diameter), some small, strongly electron-dense vesicles were found in glutaraldehyde dichromate-fixed tissue and were thought to contain NE. A variety of other vesicles were also encountered. The addition of NE to the in vitro muscle chambers caused a dose-related contraction, which was blocked by pretreatment with phentolamine in all CC strips tested. Acetylcholine in high concentration produced minimal contraction in 2 of 24 strips. Our morphologic and pharmacologic data suggest that the sympathetic nervous system may affect erection by acting not only on the penile vasculature but also by direct action on the smooth muscle of the CC itself.
George S. Benson, Joann McConnell, Larry I. Lipshultz, Joseph N. Corriere Jr., Joe Wood
Usage data is cumulative from June 2022 through June 2023.
Usage information is collected from two different sources: this site (JCI) and Pubmed Central (PMC). JCI information (compiled daily) shows human readership based on methods we employ to screen out robotic usage. PMC information (aggregated monthly) is also similarly screened of robotic usage.
Various methods are used to distinguish robotic usage. For example, Google automatically scans articles to add to its search index and identifies itself as robotic; other services might not clearly identify themselves as robotic, or they are new or unknown as robotic. Because this activity can be misinterpreted as human readership, data may be re-processed periodically to reflect an improved understanding of robotic activity. Because of these factors, readers should consider usage information illustrative but subject to change.