Molecular Biology and Physiology of Erectile Function and Dysfunction

madman

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36.1 Introduction

Erectile dysfunction (ED) refers to the inability to achieve or maintain an erection for satisfactory sexual performance. It is highly prevalent among aging men and can have a significant impact on quality of life and interpersonal relationships [1]. It was estimated in 2000 that as many as 18 million Americans aged 40–70 have some degree of ED with a growing incidence rate of 26 new cases per 1,000 annually [1]. Similar projections suggest that by the year 2025, the global prevalence may be as high as 322 million [2]. ED has well-established associations with poor general health including cardiovascular disease and diabetes, lifestyle factors, and even low socioeconomic status [3]. Therefore, the identification of ED offers a glimpse into men’s health, illuminating underlying illnesses and providing opportunities to intervene in otherwise asymptomatic men.

Over the last several decades there have been major advances in our understanding of erection physiology from the neural pathways of the sympathetic and parasympathetic nervous system down to the biochemical effectors such as nitric oxide (NO), Ras homolog A (RhoA), and cyclic adenosine monophosphate (cAMP). These discoveries have helped us better understand the pathophysiology and develop a number of effective pharmacotherapies. The aim of this chapter is to summarize the anatomical and molecular biology of erectile function, highlighting the dynamic interplay of multiple neurochemical pathways that enable male potency.





36.2 Physiology of Erectile Function
36.2.1 Neurophysiology
36.2.2 Molecular Effectors





36.3 Pathophysiology of Erectile Dysfunction
36.3.1 Vasculogenic
36.3.2 Neurogenic
36.3.3 Endocrine
36.3.4 Psychogenic
36.3.5 Drug-Induced





36.4 Conclusion

In this chapter, we summarized the molecular biology and anatomy required to produce erectile function. Erectile function depends on the interactions between multiple body systems and can be influenced by molecular effectors that balance pro- and anti-erectile function. The well-orchestrated steps result in smooth muscle dilation and improved vascular flow against venous drainage. Along this same route, there are a number of ways erectile function can be disrupted. Erectile dysfunction can have a tremendous impact on the male psyche and quality of life. Therefore, it is a critical area of research not only for symptomatic treatment but durable long-lasting cures.
 

Attachments

Figure 36.1 Coronal section of penile anatomy
1707002968951.webp
 

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Scientific Reference

Lakshman KM, Kaplan B, Travison TG, Basaria S, Knapp PE, Singh AB, LaValley MP, Mazer NA, Bhasin S. The effects of injected testosterone dose and age on the conversion of testosterone to estradiol and dihydrotestosterone in young and older men. J Clin Endocrinol Metab. 2010 Aug;95(8):3955-64.

DOI: 10.1210/jc.2010-0102 | PMID: 20534765 | PMCID: PMC2913038

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