The erectile mechanism is a sequential cascade of events, involving many chemical messengers, perhaps the most important one being nitric oxide (NO). NO is a putative neurotransmitter involved in the non-adrenergic non-cholinergic (NANC) system and is synthesized by the enzyme nitric oxide synthase (NOS). NOS has been localized in peripheral autonomic nerves innervating vascular and non-vascular smooth muscles in many organ systems. / The introduction of intracavernous injection (ICI) of vasoactive agents in 1981 was an effective means to restore erectile function for men with erectile dysfunction (ED). Recent evidence supports the theory that increased blood flow can induce the release of NO from vascular endothelium, suggesting that ICI may have positive benefits for the host. / Our study looked at (1) a new delivery system for intracavernous injection and (2) the effect of modulation of penile flow on the regulation of NOS content and activity. A canine model assessed the effectiveness of a subcutaneous drug delivery as an alternate means to ICI. Additionally, a paraplegic rat model was developed to assess the effects of chronic ICI of papaverine on the expression of NOS in the penile tissue. / Our first objective, testing a new subcutaneous drug delivery system, yielded no data due to technical difficulties. The experiment involving the rat model, our results demonstrated that ICI of papaverine significantly increased the number of NOS fibers within the penile shaft, indicating that an increase in the flow of blood within the penis can alter levels of NOS within penile tissue. This result may in part explain the observation seen in patients, whereby after 1 year of ICI, spontaneous erections return and ICI therapy may be discontinued.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.30846 |
| Date | January 1999 |
| Creators | Lieberman, Howard M. |
| Contributors | Brock, G. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Division of Surgical Research.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001802955, proquestno: MQ70550, Theses scanned by UMI/ProQuest. |
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