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Allen MS, Tostes RC. Cigarette smoking and erectile dysfunction: an updated review with a focus on pathophysiology, e-cigarettes, and smoking cessation. Sex Med Rev 2023. [DOI: 10.1093/sxmrev/qeac007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Abstract
Introduction
Cigarette smoking has major health implications and causes substantial damage to all organ systems. Approximately one-third of men are active smokers worldwide, and most men are unaware that cigarette smoking can contribute to erectile dysfunction (ED).
Objectives
This article aims to provide a comprehensive overview of research conducted on cigarette smoking and ED, with a particular focus on pathophysiology, electronic cigarettes (e-cigarettes), and smoking cessation.
Methods
A manual literature search was conducted on all research conducted on cigarette smoking and ED up to October 2022.
Results
Substantial evidence is now available showing that past and current cigarette smoking has dose-dependent associations with ED in studies controlling for age and important health comorbidities. Cigarette smoke contains nicotine, carbon monoxide, oxidant chemicals, and metals that can damage the endothelium and disrupt erectile processes. For current smokers, smoking abstinence can strengthen the endothelium and reverse diminished erectile function. The effect of e-cigarettes on endothelial damage and ED remains largely untested. E-cigarettes expose users to fine and ultrafine particles and toxins that can increase risk of cardiovascular injury, but these acute effects appear less potent than conventional cigarettes (long-term cardiovascular effects are still unknown). E-cigarettes are therefore likely to have less harmful effects on ED than conventional cigarettes.
Conclusions
Smoking cessation programs that focus on nicotine replacement therapy (transdermal patches, gum, or inhalers), behavioral counseling, social support, and education programs can be effective approaches to ED treatment in active smokers. Temporarily transferring from regular cigarettes to e-cigarettes—which transmit some of the same carcinogens as conventional cigarettes and are likely to have some long-term cardiovascular effects that disrupt erectile function—might also be useful for long-term smoking cessation and treatment of ED.
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Affiliation(s)
- Mark S Allen
- Department of Psychology and Therapeutic Studies , Leeds Trinity University, Leeds, LS18 5HD, UK
| | - Rita C Tostes
- Department of Pharmacology, University of São Paulo , São Paulo, Brazil
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2
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Kang BS, Suh SW, Yang DY, Choi BY, Lee WK. Expression and Distribution of Free Zinc in Penile Erectile Tissue. World J Mens Health 2023; 41:155-163. [PMID: 35274500 PMCID: PMC9826916 DOI: 10.5534/wjmh.210168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/16/2021] [Accepted: 12/15/2021] [Indexed: 01/21/2023] Open
Abstract
PURPOSE Several studies have shown that zinc has a significant influence on erectile function. However, no studies evaluating the cellular distribution of free zinc in penile erectile tissue have been performed. Therefore, this study aimed to test whether free zinc is present in penile tissue and whether it may be involved in the electrical stimulation (ES)-induced penile erection. MATERIALS AND METHODS The subjects for this study were 26 young (8-week-old) male C57BL/6J mice. After the cavernous nerve was exposed through a midline stomach incision, 14 mice received ES of the cavernous nerve (ES group), whereas 12 mice did not (control group). Intracavernous pressure (ICP) (consisting of 10 V at a duration of 1 min, frequency of 12 Hz and a pulse width of 1 m/s) was recorded during ES. Immediately after ICP was recorded, penile tissues were harvested for histological and biochemical analysis, including analysis of zinc transporter 3 (ZnT3) and intracellular free zinc levels. RESULTS The expression of neuronal nitric oxide synthase (nNOS) and endothelial NOS (eNOS) in penile tissue was significantly greater in the ES group than in the control group (p=0.036 and 0.016, respectively). And then, ZnT3 and intracellular free zinc were present in the penile tissue of both groups. However, ZnT3 immunofluorescence in the ES group was more intense in the dorsal nerve bundle (22% increase, p=0.032). The ES group also showed higher intensity N-(6-methoxy-8-quinolyl)-para-toluenesulfonamide (TSQ) fluorescence signals indicative of intracellular free zinc level in the penile tissue compared to the control group (49% increase in dorsal nerve bundle, p=0.001; 50% increase in corpus cavernosum, p=0.001). CONCLUSIONS The results of the study supported the expression and distribution of free zinc in penile tissue and increased levels after penile erection. Therefore, this study provides anatomical evidence for the potential role of free zinc in penile erection.
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Affiliation(s)
- Beom Seok Kang
- Department of Physiology, Hallym University College of Medicine, Chuncheon, Korea
| | - Sang Won Suh
- Department of Physiology, Hallym University College of Medicine, Chuncheon, Korea
| | - Dae Yul Yang
- Department of Urology, Kangdong Sacred Heart Hospital, Seoul, Korea
| | - Bo Young Choi
- Department of Physiology, Hallym University College of Medicine, Chuncheon, Korea
| | - Won Ki Lee
- Department of Urology, Hallym University Chuncheon Sacred Heart Hospital, Chuncheon, Korea
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3
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de Souza ILL, Ferreira EDS, Vasconcelos LHC, Cavalcante FDA, da Silva BA. Erectile Dysfunction: Key Role of Cavernous Smooth Muscle Cells. Front Pharmacol 2022; 13:895044. [PMID: 35865945 PMCID: PMC9294450 DOI: 10.3389/fphar.2022.895044] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 04/13/2022] [Indexed: 11/28/2022] Open
Abstract
Erectile dysfunction is increasingly affecting men, from the elderly to young adults, being a sexual disorder related to the inability to generate or maintain a penile erection. This disorder is related to psychosocial factors such as anxiety, depression, and low self-esteem, to organic factors such as the presence of preexisting conditions like hypertension, diabetes and dyslipidemia. The pathophysiology of the disease is related to changes in the neurotransmission of the autonomic or the non-cholinergic non-adrenergic nervous system, as well as the release of local mediators, such as thromboxane A2 and endothelin, and hormonal action. These changes lead to impaired relaxation of cavernous smooth muscle, which reduces local blood flow and impairs penile erection. Currently, therapy is based on oral vasodilation, such as sildenafil, tadalafil, vardenafil and iodenafil, or by direct administration of these agents into the corpus cavernosum or by intraurethral route, such as alprostadil and papaverine. Despite this, studies that consolidate the understanding of its pathophysiological process contribute to the discovery of new more efficient drugs for the treatment of erectile dysfunction. In this sense, in the present work an extensive survey was carried out of the mechanisms already consolidated and the most recent ones related to the development of erectile dysfunction.
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Affiliation(s)
- Iara Leão Luna de Souza
- Departamento de Ciências Biológicas e da Saúde, Universidade Estadual de Roraima, Boa Vista, Brazil
| | - Elba dos Santos Ferreira
- Programa de Pós-graduação em Produtos Naturais e Sintéticos Bioativos, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, Brazil
| | - Luiz Henrique César Vasconcelos
- Programa de Pós-graduação em Produtos Naturais e Sintéticos Bioativos, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, Brazil
- Departamento de Fisiologia e Patologia, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, Brazil
| | - Fabiana de Andrade Cavalcante
- Programa de Pós-graduação em Produtos Naturais e Sintéticos Bioativos, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, Brazil
- Departamento de Fisiologia e Patologia, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, Brazil
- *Correspondence: Fabiana de Andrade Cavalcante,
| | - Bagnólia Araújo da Silva
- Programa de Pós-graduação em Produtos Naturais e Sintéticos Bioativos, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, Brazil
- Departamento de Ciências Farmacêuticas, Centro de Ciências da Saúde, Universidade Federal da Paraíba, João Pessoa, Brazil
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4
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Kozacioglu Z, Vatansever HS, Onal T, Kutlu N, Ozel F, Gunlusoy B, Gumus BH. Histologic and physiologic analysis of the relationship between the dorsal nerve of the penis and the corpus cavernosum on a rat model. A complementary pathway on the innervation of penile erection? Neurourol Urodyn 2021; 41:188-194. [PMID: 34750848 DOI: 10.1002/nau.24829] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 09/22/2021] [Accepted: 10/22/2021] [Indexed: 11/10/2022]
Abstract
AIM The dorsal nerve of the penis (DNP) is the terminal branch of the pudendal nerve which is responsible for the somatic innervation of the penis. This study aims to outline any direct role of the DNP in the hemodynamics of erection histologically and physiologically. MATERIALS AND METHODS Fifteen Wistar albino rats were sorted into the electrical activity (n = 6), intracavernous pressure (n = 4), and control (n = 5) groups. The dorsal nerve was electrostimulated and the simultaneous changes in intracavernous pressure and smooth muscle activity were recorded. Penile tissues were collected, fixed, and sectioned, the slides were stained with either hematoxylin-eosin for morphological evaluation or using the indirect immunoperoxidase technique to analyze the distributions of eNOS, iNOS, and nNOS. RESULTS During electrostimulation, there was a simultaneous statistically significant decrease in the electrical activity inside the corpora in electromyography and an increase in intracavernous pressure. eNOS and iNOS immunoreactivities were higher in the study group than in the control group. nNOS immunoreactivity was moderate in both study and control groups. CONCLUSION Some fibers in the dorsal nerve of penis continue into the corpora cavernosa through the tunica albuginea and have an active, direct role in the hemodynamic process of erection, which may be complementary to the main route of innervation.
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Affiliation(s)
- Zafer Kozacioglu
- Urology Clinic, Medical Park Hospital, Izmir Economy University, Izmir, Turkey
| | - H Seda Vatansever
- Department of Histology and Embryology, Faculty of Medicine, Manisa Celal Bayar University, Manisa, Turkey.,DESAM Institute, Near East University, Nicosia, Cyprus
| | - Tuna Onal
- Department of Histology and Embryology, Faculty of Medicine, Manisa Celal Bayar University, Manisa, Turkey
| | - Necip Kutlu
- Department of Physiology, Faculty of Medicine, Manisa Celal Bayar University, Manisa, Turkey
| | - Fehmi Ozel
- Department of Physiology, Faculty of Medicine, Manisa Celal Bayar University, Manisa, Turkey
| | - Bulent Gunlusoy
- Urology Clinic, Bozyaka Training and Research Hospital, Izmir University of Health Sciences, Izmir, Turkey
| | - Bilal H Gumus
- Department of Urology, Faculty of Medicine, Manisa Celal Bayar University, Manisa, Turkey
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5
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Cripps SM, Mattiske DM, Pask AJ. Erectile Dysfunction in Men on the Rise: Is There a Link with Endocrine Disrupting Chemicals? Sex Dev 2021; 15:187-212. [PMID: 34134123 DOI: 10.1159/000516600] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 04/18/2021] [Indexed: 11/19/2022] Open
Abstract
Erectile dysfunction (ED) is one of the most prevalent chronic conditions affecting men. ED can arise from disruptions during development, affecting the patterning of erectile tissues in the penis and/or disruptions in adulthood that impact sexual stimuli, neural pathways, molecular changes, and endocrine signalling that are required to drive erection. Sexual stimulation activates the parasympathetic system which causes nerve terminals in the penis to release nitric oxide (NO). As a result, the penile blood vessels dilate, allowing the penis to engorge with blood. This expansion subsequently compresses the veins surrounding the erectile tissue, restricting venous outflow. As a result, the blood pressure localised in the penis increases dramatically to produce a rigid erection, a process known as tumescence. The sympathetic pathway releases noradrenaline (NA) which causes detumescence: the reversion of the penis to the flaccid state. Androgen signalling is critical for erectile function through its role in penis development and in regulating the physiological processes driving erection in the adult. Interestingly, estrogen signalling is also implicated in penis development and potentially in processes which regulate erectile function during adulthood. Given that endocrine signalling has a prominent role in erectile function, it is likely that exposure to endocrine disrupting chemicals (EDCs) is a risk factor for ED, although this is an under-researched field. Thus, our review provides a detailed description of the underlying biology of erectile function with a focus on the role of endocrine signalling, exploring the potential link between EDCs and ED based on animal and human studies.
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Affiliation(s)
- Samuel M Cripps
- School of BioSciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - Deidre M Mattiske
- School of BioSciences, The University of Melbourne, Melbourne, Victoria, Australia
| | - Andrew J Pask
- School of BioSciences, The University of Melbourne, Melbourne, Victoria, Australia
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Aoun F, Alkassis M, Tayeh GA, Chebel JA, Semaan A, Sarkis J, Mansour R, Mjaess G, Albisinni S, Absil F, Bollens R, Roumeguère T. Sexual dysfunction due to pudendal neuralgia: a systematic review. Transl Androl Urol 2021; 10:2500-2511. [PMID: 34295736 PMCID: PMC8261452 DOI: 10.21037/tau-21-13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 01/26/2021] [Indexed: 01/16/2023] Open
Abstract
Background The pudendal nerve is considered as the main nerve of sexuality. Pudendal neuralgia is an underdiagnosed disease in clinical practice. The aim of this systematic review is to highlight the role of pudendal neuralgia on sexual dysfunction in both sexes. Methods A PubMed search was performed using the following keywords: “Pudendal” AND “Sexual dysfunction” or “Erectile dysfunction” or “Ejaculation” or “Persistent sexual arousal” or “Dyspareunia” or “Vulvodynia”. The search involved patients having sexual dysfunction due to pudendal neuralgia. Treatment received was also reported. Results Five case series, seven cohort studies, two pilot studies, and three randomized clinical trials were included in this systematic review. Pudendal nerve and/or artery entrapment, or pudendal neuralgia, is a reversible cause of multiple sexual dysfunctions. Interventions such as anesthetic injections, neurolysis, and decompression are reported as potential treatment modalities. There are no studies describing the role of pudendal canal syndrome in the pathophysiology or treatment of delayed ejaculation or penile shortening. Discussion Pudendal neuralgia is an underestimated yet important cause of persistent genital arousal, erectile dysfunction (ED), premature ejaculation (PE), ejaculation pain, and vulvodynia. Physicians should be aware of this entity and examine the pudendal canal in such patients before concluding an idiopathic cause of sexual dysfunction.
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Affiliation(s)
- Fouad Aoun
- Urology Department, Hôtel Dieu de France, Université Saint Joseph, Beirut, Lebanon.,Urology Department, Institut Jules Bordet, Université Libre de Bruxelles, Brussels, Belgium
| | - Marwan Alkassis
- Urology Department, Hôtel Dieu de France, Université Saint Joseph, Beirut, Lebanon
| | - Georges Abi Tayeh
- Urology Department, Hôtel Dieu de France, Université Saint Joseph, Beirut, Lebanon
| | - Josselin Abi Chebel
- Urology Department, Hôtel Dieu de France, Université Saint Joseph, Beirut, Lebanon
| | - Albert Semaan
- Urology Department, Hôtel Dieu de France, Université Saint Joseph, Beirut, Lebanon
| | - Julien Sarkis
- Urology Department, Hôtel Dieu de France, Université Saint Joseph, Beirut, Lebanon
| | - Raymond Mansour
- Urology Department, Hôtel Dieu de France, Université Saint Joseph, Beirut, Lebanon
| | - Georges Mjaess
- Urology Department, Hôtel Dieu de France, Université Saint Joseph, Beirut, Lebanon.,Urology Department, Cliniques Universitaires de Bruxelles, Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium
| | - Simone Albisinni
- Urology Department, Cliniques Universitaires de Bruxelles, Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium
| | - Fabienne Absil
- Urology department, Centre Hospitalier EpiCURA, Site de Ath, Ath, Belgium
| | - Renaud Bollens
- Urology department, Centre Hospitalier de Wallonie Picarde, Tournai, Belgium
| | - Thierry Roumeguère
- Urology Department, Institut Jules Bordet, Université Libre de Bruxelles, Brussels, Belgium.,Urology Department, Cliniques Universitaires de Bruxelles, Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium
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7
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The synthetic peptide PnPP-19 potentiates erectile function via nNOS and iNOS. Nitric Oxide 2021; 113-114:23-30. [PMID: 33915274 DOI: 10.1016/j.niox.2021.04.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 04/19/2021] [Accepted: 04/21/2021] [Indexed: 01/27/2023]
Abstract
PnPP-19 peptide has a primary sequence design based on molecular modeling studies of PnTx2-6 toxin. It comprises the amino acid residues that are potentially significant for the pharmacological action of PnTx2-6. Ex vivo and in vivo experiments in normotensive, hypertensive, or diabetic murine models have shown a significant improvement in penile erection after administration of PnPP-19. Given the potential use of PnPP-19 in pharmaceutical formulations to treat erectile dysfunction and the lack of information concerning its mode of action, the present work investigates its activities on the nitrergic system. PnPP-19 induced a significant increase in nitric oxide (NO) and cGMP levels in corpus cavernosum (cc). These effects were inhibited by l-NAME, a non-selective inhibitor of nitric oxide synthase (NOS); were partially inhibited by 7- Nitroindazole, a selective inhibitor of neuronal NOS (nNOS); and were abolished by L-NIL, a selective inhibitor of inducible NOS (iNOS). This potentiating effect was not affected by atropine. PnPP-19 also led to changes in mRNA levels, protein expression and phosphorylation at specific sites of NOS, in cc. Assays using cavernous tissue from knockout mice to endothelial NOS (eNOS), nNOS or iNOS showed that PnPP-19 potentiates relaxation only in eNOS-knockout mice, which suggests an essential role for nNOS. Surprisingly, iNOS enhanced the potentiation of erectile function evoked by PnPP-19. Our results demonstrate that this new synthetic peptide potentiates erectile function via nitric oxide activation and reinforce its role as a new pharmacological tool for the treatment of erectile dysfunction.
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8
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Seppan P, Muhammed I, Mohanraj KG, Lakshmanan G, Premavathy D, Muthu SJ, Wungmarong Shimray K, Sathyanathan SB. Therapeutic potential of Mucuna pruriens (Linn.) on ageing induced damage in dorsal nerve of the penis and its implication on erectile function: an experimental study using albino rats. Aging Male 2020; 23:313-326. [PMID: 29447059 DOI: 10.1080/13685538.2018.1439005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
OBJECTIVE To study the effect of ethanolic seed extract of Mucuna pruriens on damaged dorsal nerve of the penis (DNP) in aged rat in relation to penile erection. METHODS The rats were divided into four groups Young (3 months), Aged (24 - 28 months), Aged + M. pruriens, and Young + M. pruriens (200 mg/kg b.w/60 days) and were subjected to the hypophysial - gonadal axis, nerve conduction velocity (NCV), and penile reflex. DNP sections were stained with nitric oxide synthase (nNOS), nicotinamide adenine dinucleotide phosphate (NaDPH) diaphorase, androgen receptor (AR), and osmium tetroxide. Terminal deoxynucleotidyl transferase (TdT) dUTP Nick-End Labeling (TUNEL) staining, electron microscopy(EM) and histometric analyses were done. RESULTS Significant disturbance in hypophysial - gonadal axis was noted in aged rat. With reduced number of myelinated fibers, diameter, vacuolization, indentation of the myelin sheath, and degeneration. nNOS and its cofactor (NaDPH diaphorase) were reduced in aged rat DNP. NCV was slow in aged rats and concomitant poor penile reflex was also noted. AR showed reduced expression in aged rat DNP when compared to young and control groups. TUNEL positive cells were increased in aged rat DNP. These pathological changes were remarkably reduced or recovered in M. pruriens treated aged rats. CONCLUSIONS The results indicate a multi-factorial therapeutic activity in penile innervations towards sustaining the penile erection in the presence of the extract in aged rats and justifying the claim of traditional usage.
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Affiliation(s)
- Prakash Seppan
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Ibrahim Muhammed
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Karthik Ganesh Mohanraj
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
- Department of Anatomy, Saveetha Dental College and Hospital, Chennai, India
| | - Ganesh Lakshmanan
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Dinesh Premavathy
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Sakthi Jothi Muthu
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Khayinmi Wungmarong Shimray
- Department of Anatomy, Dr. Arcot Lakshmanasamy Mudaliar Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai, India
| | - Sathya Bharathy Sathyanathan
- Department of Electrical and Electronics Engineering, Loyola-ICAM College of Engineering and Technology, Chennai, India
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9
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Xavier FE. Nitrergic perivascular innervation in health and diseases: Focus on vascular tone regulation. Acta Physiol (Oxf) 2020; 230:e13484. [PMID: 32336027 DOI: 10.1111/apha.13484] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 04/14/2020] [Accepted: 04/16/2020] [Indexed: 12/12/2022]
Abstract
For a long time, the vascular tone was considered to be regulated exclusively by tonic innervation of vasoconstrictor adrenergic nerves. However, accumulating experimental evidence has revealed the existence of nerves mediating vasodilatation, including perivascular nitrergic nerves (PNN), in a wide variety of mammalian species. Functioning of nitrergic vasodilator nerves is evidenced in several territories, including cerebral, mesenteric, pulmonary, renal, penile, uterine and cutaneous arteries. Nitric oxide (NO) is the main neurogenic vasodilator in cerebral arteries and acts as a counter-regulatory mechanism for adrenergic vasoconstriction in other vascular territories. In the penis, NO relaxes the vascular and cavernous smooth muscles leading to penile erection. Furthermore, when interacting with other perivascular nerves, NO can act as a neuromodulator. PNN dysfunction is involved in the genesis and maintenance of vascular disorders associated with arterial and portal hypertension, diabetes, ageing, obesity, cirrhosis and hormonal changes. For example defective nitrergic function contributes to enhanced sympathetic neurotransmission, vasoconstriction and blood pressure in some animal models of hypertension. In diabetic animals and humans, dysfunctional nitrergic neurotransmission in the corpus cavernosum is associated with erectile dysfunction. However, in some vascular beds of hypertensive and diabetic animals, an increased PNN function has been described as a compensatory mechanism to the increased vascular resistance. The present review summarizes current understanding on the role of PNN in control of vascular tone, its alterations under different conditions and the associated mechanisms. The knowledge of these changes can serve to better understand the mechanisms involved in these disorders and help in planning new treatments.
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Affiliation(s)
- Fabiano E. Xavier
- Departamento de Fisiologia e Farmacologia Centro de Biociências Universidade Federal de Pernambuco Recife Brazil
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10
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Pharmacology and perspectives in erectile dysfunction in man. Pharmacol Ther 2020; 208:107493. [PMID: 31991196 DOI: 10.1016/j.pharmthera.2020.107493] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 11/05/2019] [Indexed: 12/15/2022]
Abstract
Penile erection is a perfect example of microcirculation modulated by psychological factors and hormonal status. It is the result of a complex neurovascular process that involves the integrative synchronized action of vascular endothelium; smooth muscle; and psychological, neuronal, and hormonal systems. Therefore, the fine coordination of these events is essential to maintain penile flaccidity or allow erection; an alteration of these events leads to erectile dysfunction (ED). ED is defined as the consistent or recurrent inability of a man to attain and/or maintain a penile erection sufficient for sexual activity. A great boost to this research field was given by commercialization of phosphodiesterase-5 (PDE5) inhibitors. Indeed, following the discovery of sildenafil, research on the mechanisms underlying penile erection has had an enormous boost, and many preclinical and clinical papers have been published in the last 10 years. This review is structured to provide an overview of the mediators and peripheral mechanism(s) involved in penile function in men, the drugs used in therapy, and the future prospective in the management of ED. Indeed, 30% of patients affected by ED are classified as "nonresponders," and there is still an unmet need for therapeutic alternatives. A flowchart suggesting the guidelines for ED evaluation and the ED pharmacological treatment is also provided.
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11
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Steadman CJ, Vangoor SS, Hubscher CH. Telemetric monitoring of penile pressure during mating in rats after chronic spinal cord injury. Am J Physiol Regul Integr Comp Physiol 2019; 317:R673-R683. [PMID: 31483153 DOI: 10.1152/ajpregu.00171.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
In men with a spinal cord injury (SCI), erectile function, ejaculation, and fertility are severely impaired. The present study utilized a telemetric pressure transducer implanted into the corpus cavernosum of the penis to examine sexual function during awake mating behavior in a rat contusion model with a range of Infinite Horizon Impactor forces distributed between 150 and 215 kdyn. The mating behavior paradigm included examination of the counts, average pressure, and average duration for mounts, intromissions, and ejaculations. Male Wistar rats were mated with receptive females in 30-min sessions preinjury (sexual acclimation) and once per week for 6 wk beginning after a 2-wk recovery period post-SCI. All SCI animals had significant deficits in sexual function in the parameters measured. These deficiencies were more prevalent in a subset having less than 20% white matter sparing, likely a reflection of the extent of bilateral spino-bulbo-spinal sexual circuitry disruption at the lesion epicenter. The resulting discoordination of the autonomic and somatic reflex control of erection and ejaculation recorded using telemetry devices in an awake, behaving animal model provides an effective means of gauging sexual function deficits after SCI and could have utility for quantifying recovery after a therapeutic intervention.
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Affiliation(s)
- Casey J Steadman
- Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky
| | - Sai S Vangoor
- Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky
| | - Charles H Hubscher
- Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky.,Kentucky Spinal Cord Injury Research Center, Louisville, Kentucky
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12
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Cunha JPD, Lizarte FS, Novais PC, Gattas D, Carvalho CAMD, Tirapelli DPDC, Molina CAF, Tirapelli LF, Tucci S. Expression profiles of eNOS, iNOS and microRNA-27b in the corpus cavernosum of rats submitted to chronic alcoholism and Diabetes mellitus. Acta Cir Bras 2017; 32:38-45. [PMID: 28225916 DOI: 10.1590/s0102-865020170105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 12/18/2016] [Indexed: 01/23/2023] Open
Abstract
Purpose: To evaluate the expression of endothelial and inducible NOS in addition to the miRNA-27b in the corpus cavernosum and peripheral blood of healthy rats, diabetic rats, alcoholic rats and rats with both pathologies. Methods: Forty eight Wistar rats were divided into four groups: control (C), alcoholic (A), diabetic (D) and alcoholic-diabetic (AD). Samples of the corpus cavernosum were prepared to study protein expressions of eNOS and iNOS by immunohistochemistry and expression of miRNA-27b in the corpus cavernosum and peripheral blood. Results: Immunohistochemistry for eNOS and iNOS showed an increase in cavernosal smooth muscle cells in the alcoholic, diabetic and alcoholic-diabetic groups when compared with the control group. Similarly, the mRNA levels for eNOS were increased in cavernosal smooth muscle (CSM) in the alcoholic, diabetic and alcoholic-diabetic groups and miRNA-27b were decreased in CSM in the alcoholic, diabetic and alcoholic-diabetic groups. Conclusion: The major new finding of our study was an impairment of relaxation of cavernosal smooth muscle in alcoholic, diabetic, and alcoholic-diabetic rats that involved a decrease in the nitric oxide pathway by endothelium-dependent mechanisms accompanied by a change in the corpus cavernosum contractile sensitivity.
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Affiliation(s)
- Joao Paulo da Cunha
- Master, Postgraduate Program in Clinical Surgery, Department of Surgery and Anatomy, School of Medicine of Ribeirao Preto, Universidade de São Paulo (USP), Ribeirao Preto-SP, Brazil. Acquisition and interpretation of data, manuscript writing
| | - Fermino Sanches Lizarte
- Pos-doctoral Fellow student, Postgraduate Program in Clinical Surgery, Department of Surgery and Anatomy, School of Medicine of Ribeirao Preto, USP, Ribeirao Preto-SP, Brazil. Technical procedures, manuscript writing
| | - Paulo Cezar Novais
- Assistant Professor, Department of Health Sciences, Universidade de Marília, Brazil. Technical procedures, manuscript writing
| | - Daniela Gattas
- Fellow Master degree, Postgraduate Program in Clinical Surgery, Department of Surgery and Anatomy, School of Medicine of Ribeirao Preto, USP, Ribeirao Preto-SP, Brazil. Manuscript writing
| | - Camila Albuquerque Mello de Carvalho
- Assistant Professor, Institute of Biological and Health Sciences, Federal University of Alagoas, Alagoas, Brazil and PhD Student, Clinical Surgery Postgraduate Program, Department of Surgery and Anatomy, School of Medicine of Ribeirao Preto, USP, Ribeirao Preto-SP, Brazil. Manuscript writing
| | - Daniela Pretti da Cunha Tirapelli
- Assistant Professor, Department of Surgery and Anatomy, Surgical Clinic Program, School of Medicine of Ribeirao Preto, USP, Ribeirao Preto-SP, Brazil, Scientific and intellectual content of the study
| | - Carlos Augusto Fernandes Molina
- Assistant Professor, Division of Urology, Department of Surgery and Anatomy, School of Medicine of Ribeirao Preto, USP, Ribeirao Preto-SP, Brazil. Scientific and intellectual content of the study
| | - Luis Fernando Tirapelli
- Associate Professor, Department of Surgery and Anatomy, School of Medicine of Ribeirao Preto, USP, Ribeirao Preto-SP, Brazil. Scientific and intellectual content of the study
| | - Silvio Tucci
- Associate Professor, Division of Urology, Department of Surgery and Anatomy, School of Medicine of Ribeirao Preto, USP, Ribeirao Preto-SP, Brazil. Concept, design, intellectual and scientific content of the study; critical revision; supervised all phases of the study
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Shridharani AN, Brant WO. The treatment of erectile dysfunction in patients with neurogenic disease. Transl Androl Urol 2016; 5:88-101. [PMID: 26904415 PMCID: PMC4739980 DOI: 10.3978/j.issn.2223-4683.2016.01.07] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Erectile dysfunction (ED) related to compromise of the nervous system is an increasingly common occurrence. This may be due to the multifactorial nature of ED, the myriad of disorders affecting the neurotransmission of erectogenic signals, and improved awareness and diagnosis of ED. Nevertheless, neurogenic ED remains poorly understood and characterized. Disease related factors such as depression, decreased physical and mental function, the burden of chronic illness, and loss of independence may preclude sexual intimacy and lead to ED as well. The amount of data regarding treatment options in subpopulations of differing neurologic disorders remains scarce except for men with spinal cord injury. The treatment options including phosphodiesterase inhibitors, intracavernosal or intraurethral vasoactive agents, vacuum erection devices (VED) and penile prosthetic implantation remain constant. This review discusses the options in specific neurologic conditions, and briefly provides insight into new and future developments that may reshape the management of neurogenic ED.
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Affiliation(s)
- Anand N Shridharani
- 1 Department of Urology, University of Tennessee College of Medicine, Chattanooga, TN, USA ; 2 Division of Urology, University of Utah, Salt Lake City, Utah, USA
| | - William O Brant
- 1 Department of Urology, University of Tennessee College of Medicine, Chattanooga, TN, USA ; 2 Division of Urology, University of Utah, Salt Lake City, Utah, USA
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14
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Muraoka K, Hinata N, Morizane S, Honda M, Sejima T, Murakami G, Tewari AK, Takenaka A. Site-dependent and interindividual variations in Denonvilliers' fascia: a histological study using donated elderly male cadavers. BMC Urol 2015; 15:42. [PMID: 25962380 PMCID: PMC4433060 DOI: 10.1186/s12894-015-0034-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2014] [Accepted: 04/22/2015] [Indexed: 11/14/2022] Open
Abstract
Background Site-dependent and interindividual histological differences in Denonvilliers’ fascia (DF) are not well understood. This study aimed to examine site-dependent and interindividual differences in DF and to determine whether changes in the current approach to radical prostatectomy are warranted in light of these histological findings. Methods Twenty-five donated male cadavers (age range, 72–95 years) were examined. These cadavers had been donated to Sapporo Medical University for research and education on human anatomy. Their use for research was approved by the university ethics committee. Horizontal sections (15 cadavers) or sagittal sections (10 cadavers) were prepared at intervals of 2–5 mm for hematoxylin and eosin staining. Elastic–Masson staining and immunohistochemical staining were also performed, using mouse monoclonal anti-human alpha-smooth muscle actin to stain connective tissues and mouse monoclonal anti-human S100 protein to stain nerves. Results We observed that DF consisted of disorderly, loose connective tissue and structures resembling “leaves”, which were interlacing and adjacent to each other, actually representing elastic or smooth muscle fibers. Variations in DF were observed in the following: 1) configuration of multiple leaves, including clear, unclear, or fragmented behind the body and tips of the seminal vesicles, depending on the site; 2) connection with the lateral pelvic fascia at the posterolateral angle of the prostate posterior to the neurovascular bundles, being clear, unclear, or absent; 3) all or most leaves of DF fused with the prostatic capsule near the base of the seminal vesicles, and periprostatic nerves were embedded in the leaves at the fusion site; and 4) some DF leaves fused with the prostatic capsule anteriorly and/or the fascia propria of the rectum posteriorly. Conclusions Site-dependent and interindividual variations in DF were observed in donated elderly male cadavers. All or most DF leaves are fused with the prostatic capsule near the base of the seminal vesicles and some DF leaves are fused with the fascia propria of the rectum posterior. Based on our results, surgeons should be aware of variations and search for them to create a suitable dissection plane to avoid iatrogenic positive margins and rectal injury.
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Affiliation(s)
- Kuniyasu Muraoka
- Division of Urology, Department of Surgery, Tottori University Faculty of Medicine, Yonago, 683-8504, Japan.
| | - Nobuyuki Hinata
- Department of Urology, Kobe University Graduate School of Medicine, Kobe, Japan.
| | - Shuichi Morizane
- Division of Urology, Department of Surgery, Tottori University Faculty of Medicine, Yonago, 683-8504, Japan.
| | - Masashi Honda
- Division of Urology, Department of Surgery, Tottori University Faculty of Medicine, Yonago, 683-8504, Japan.
| | - Takehiro Sejima
- Division of Urology, Department of Surgery, Tottori University Faculty of Medicine, Yonago, 683-8504, Japan.
| | - Gen Murakami
- Division of Internal Medicine, Iwamizawa Kojin-kai Hospital, Iwamizawa, Japan.
| | | | - Atsushi Takenaka
- Division of Urology, Department of Surgery, Tottori University Faculty of Medicine, Yonago, 683-8504, Japan.
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Understanding and targeting the Rho kinase pathway in erectile dysfunction. Nat Rev Urol 2014; 11:622-8. [PMID: 25311680 DOI: 10.1038/nrurol.2014.278] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Erectile dysfunction (ED) is a common disorder that affects a quarter of US men, and has many causes, including endothelial impairment, low testosterone levels, prior surgical manipulation, and/or psychogenic components. Penile erection is a complex process requiring neurally mediated relaxation of arteriolar smooth muscle and engorgement of cavernosal tissues, mediated by nitric oxide (NO). Current medical therapies for ED largely seek to maximize endogenous NO signalling. Certain aetiologies, including diabetes, are difficult to treat with current modalities, emphasizing the need for new molecular targets. Research has demonstrated the importance of RhoA-Rho-associated protein kinase (ROCK) signalling in maintaining a flaccid penile state, and inhibition of RhoA-ROCK signalling potentiates smooth-muscle relaxation in an NO-independent manner. The mechanisms and effects of RhoA-ROCK signalling and inhibition suggest that the RhoA-ROCK pathway could prove to be a new therapeutic target for the treatment of ED.
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Abstract
Erectile dysfunction (ED) has an adverse impact on men's quality of life. Penile erection, which is regulated by nerves that are innervated into the erectile tissue, can be affected by functional or anatomical trauma of the perineal region, including specific structures of the penis, causing ED. Penile erection is neurologically controlled by the autonomic nervous system. Therefore, it is of utmost importance to understand the neurogenic structure of the erectile tissue and the types of neurotransmitters involved in the penile erection process. Here, we highlight the basic clinical anatomy and erectile function of the penis. Understanding the clinical connotation of the relationship between penile erectile structure and function may provide fresh insights for identifying the main mechanisms involved in ED and help develop surgical techniques for the treatment of ED.
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Bond C, Cakir OO, McVary KT, Podlasek CA. Nitric Oxide Synthase is Necessary for Normal Urogenital Development. ANDROLOGY : OPEN ACCESS 2013; 2:108. [PMID: 24900949 PMCID: PMC4041737 DOI: 10.4172/2167-0250.1000108] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Introduction Neuronal nitric oxide synthase (NOS-I) is significantly decreased with Cavernous Nerve (CN) injury in Erectile Dysfunction (ED) models. Increased apoptosis and collagen deposition accompany decreased NOS/CN injury, however these changes are typically attributed to the altered signaling of other factors, and a contribution of NOS in maintenance of urogenital structures has not previously been examined. Morphological changes in the corpora cavernosa occur at the same time as decreased NOS, suggesting a potential connection between decreased/inhibited NOS and morphological changes associated with ED. In this study we propose that NOS impacts urogenital morphology during development and will examine this hypothesis by NOS inhibition with L-NAME. Methods Primary outcomes were H&E, western and TUNEL to determine if penis, prostate and bladder morphology were altered with L-NAME treatment of Postnatal day 4 (P4) Sprague Dawley rats for 8 days. Tissue weight and immunohistochemical analysis for NOS were performed. Secondary evaluation of NOS-I regulation by Sonic Hedgehog (SHH) was examined by SHH inhibition in the pelvic ganglia (PG) and NOS-I protein was quantified by western in the PG/CN and penis. Nos abundance was quantified by RT-PCR during urogenital development and after CN injury. Results Apoptosis increased and penis, prostate and bladder morphology were altered with L-NAME. NOS inhibition decreased bladder weight 25%. SHH inhibition decreased NOS-I 35% in the PG/CN and 47% in the penis. Nos-III expression spiked within the first two weeks after birth in the penis but remained abundant in the adult. In the prostate, Nos-III was abundant immediately after birth and declined steadily with age. Nos-I expression in the PG/CN decreased sharply with CN injury and returned to baseline by 7 days. Conclusions NOS is required for normal urogenital development. Since NOS is decreased with ED, it may contribute to the abnormal morphology observed in ED patients and animal models.
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Affiliation(s)
- Christopher Bond
- Department of Urology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Omer Onur Cakir
- Department of Urology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
| | - Kevin T McVary
- Division of Urology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - Carol A Podlasek
- Department of Urology, Northwestern University, Feinberg School of Medicine, Chicago, IL, USA
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Doshi SB, Khullar K, Sharma RK, Agarwal A. Role of reactive nitrogen species in male infertility. Reprod Biol Endocrinol 2012; 10:109. [PMID: 23241221 PMCID: PMC3558381 DOI: 10.1186/1477-7827-10-109] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 12/06/2012] [Indexed: 12/26/2022] Open
Abstract
Reactive nitrogen species (RNS) is a subset of free oxygen radicals called reactive oxygen species (ROS). Physiological levels of ROS are necessary to maintain the reproductive functions such as cell signaling, tight junction regulation, production of hormones, capacitation, acrosomal reaction, sperm motility, and zona pellucida binding. However, an excess of RNS can adversely affect reproductive potential by causing testicular dysfunction, decreased gonadotropin secretion, and abnormal semen parameters. Because such levels of RNS have been demonstrated in males with fertility problems and routine semen analysis has not been able to accurately predict IVF outcomes, it is imperative that novel strategies be developed in order to both assess and treat oxidative stress. This article describes both physiological and pathological roles of this unique subset of ROS.
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Affiliation(s)
- Sejal B Doshi
- Center for Reproductive Medicine, Cleveland Clinic, Euclid Avenue, Cleveland, OH, USA
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Blunt cavernous nerve injury: A new animal model mimicking postradical prostatectomy neurogenic impotence. Urol Oncol 2012; 2:158-62. [PMID: 21224162 DOI: 10.1016/s1078-1439(96)00075-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Our goal was to develop an animal model of cavernous nerve injury similar to that encountered among patients having undergone a successful nerve sparing radical prostatectomy and to compare patterns of nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase staining to quality of erections using the newly developed model. We studied 50 mature Sprague Dawley rats, which were divided into five equal groups. Animals were either observed (sham), underwent an exploratory laparotomy, underwent moderate or severe percussive injury to both cavernous nerves, or underwent ablation of both cavernous nerves. Between 28 and 30 days later, all animals underwent electrostimulation and simultaneous recording of intracavernosal pressure. After sacrifice, penes were harvested and penile tissue NADPH-diaphorase staining pattern was assessed. Severity of cavernous nerve percussive injury and NADPH-diaphorase staining patterns correlated with the quality of recorded erections. This model is a useful experimental tool for research in the field of erectile dysfunction such as is encountered following a successful nerve sparing radical prostatectomy. Penile biopsy assessing NADPH-diaphorase staining may potentially prove to be a useful minimally-invasive diagnostic modality quantifying neurogenic erectile function among patients following radical prostatectomy.
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Cyclic AMP-dependent phosphorylation of neuronal nitric oxide synthase mediates penile erection. Proc Natl Acad Sci U S A 2012; 109:16624-9. [PMID: 23012472 DOI: 10.1073/pnas.1213790109] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Nitric oxide (NO) generated by neuronal NO synthase (nNOS) initiates penile erection, but has not been thought to participate in the sustained erection required for normal sexual performance. We now show that cAMP-dependent phosphorylation of nNOS mediates erectile physiology, including sustained erection. nNOS is phosphorylated by cAMP-dependent protein kinase (PKA) at serine(S)1412. Electrical stimulation of the penile innervation increases S1412 phosphorylation that is blocked by PKA inhibitors but not by PI3-kinase/Akt inhibitors. Stimulation of cAMP formation by forskolin also activates nNOS phosphorylation. Sustained penile erection elicited by either intracavernous forskolin injection, or augmented by forskolin during cavernous nerve electrical stimulation, is prevented by the NOS inhibitor L-NAME or in nNOS-deleted mice. Thus, nNOS mediates both initiation and maintenance of penile erection, implying unique approaches for treating erectile dysfunction.
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d'Emmanuele di Villa Bianca R, Mitidieri E, Fusco F, D'Aiuto E, Grieco P, Novellino E, Imbimbo C, Mirone V, Cirino G, Sorrentino R. Endogenous urotensin II selectively modulates erectile function through eNOS. PLoS One 2012; 7:e31019. [PMID: 22319601 PMCID: PMC3271091 DOI: 10.1371/journal.pone.0031019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 12/30/2011] [Indexed: 11/22/2022] Open
Abstract
Background Urotensin II (U-II) is a cyclic peptide originally isolated from the neurosecretory system of the teleost fish and subsequently found in other species, including man. U-II was identified as the natural ligand of a G-protein coupled receptor, namely UT receptor. U-II and UT receptor are expressed in a variety of peripheral organs and especially in cardiovascular tissue. Recent evidence indicates the involvement of U-II/UT pathway in penile function in human, but the molecular mechanism is still unclear. On these bases the aim of this study is to investigate the mechanism(s) of U-II-induced relaxation in human corpus cavernosum and its relationship with L-arginine/Nitric oxide (NO) pathway. Methodology/Principal Findings Human corpus cavernosum tissue was obtained following in male-to-female transsexuals undergoing surgical procedure for sex reassignment. Quantitative RT-PCR clearly demonstrated the U-II expression in human corpus cavernosum. U-II (0.1 nM–10 µM) challenge in human corpus cavernosum induced a significant increase in NO production as revealed by fluorometric analysis. NO generation was coupled to a marked increase in the ratio eNOS phosphorilated/eNOS as determined by western blot analysis. A functional study in human corpus cavernosum strips was performed to asses eNOS involvement in U-II-induced relaxation by using a pharmacological modulation. Pre-treatment with both wortmannin or geldanamycinin (inhibitors of eNOS phosphorylation and heath shock protein 90 recruitment, respectively) significantly reduced U-II-induced relaxation (0.1 nM–10 µM) in human corpus cavernosum strips. Finally, a co-immunoprecipitation study demonstrated that UT receptor and eNOS co-immunoprecipitate following U-II challenge of human corpus cavernosum tissue. Conclusion/Significance U-II is endogenously synthesized and locally released in human corpus cavernosum. U-II elicited penile erection through eNOS activation. Thus, U-II/UT pathway may represent a novel therapeutical target in erectile dysfunction.
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Affiliation(s)
- Roberta d'Emmanuele di Villa Bianca
- Interdepartmental Research Centre for Sexual Medicine (CIRMS), University of Naples, Federico II, Naples, Italy
- Department of Experimental Pharmacology, University of Naples, Federico II, Naples, Italy
| | - Emma Mitidieri
- Department of Experimental Pharmacology, University of Naples, Federico II, Naples, Italy
| | - Ferdinando Fusco
- Interdepartmental Research Centre for Sexual Medicine (CIRMS), University of Naples, Federico II, Naples, Italy
| | - Elena D'Aiuto
- Section of Clinical Immunology, Department of Clinical and Experimental Medicine, Second University of Naples, Naples, Italy
| | - Paolo Grieco
- Department of Pharmaceutical and Toxicological Chemistry, University of Naples, Federico II, Naples, Italy
| | - Ettore Novellino
- Department of Pharmaceutical and Toxicological Chemistry, University of Naples, Federico II, Naples, Italy
| | - Ciro Imbimbo
- Interdepartmental Research Centre for Sexual Medicine (CIRMS), University of Naples, Federico II, Naples, Italy
| | - Vincenzo Mirone
- Interdepartmental Research Centre for Sexual Medicine (CIRMS), University of Naples, Federico II, Naples, Italy
| | - Giuseppe Cirino
- Interdepartmental Research Centre for Sexual Medicine (CIRMS), University of Naples, Federico II, Naples, Italy
- Department of Experimental Pharmacology, University of Naples, Federico II, Naples, Italy
| | - Raffaella Sorrentino
- Interdepartmental Research Centre for Sexual Medicine (CIRMS), University of Naples, Federico II, Naples, Italy
- Department of Experimental Pharmacology, University of Naples, Federico II, Naples, Italy
- * E-mail:
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Penile erectile activity of dinitrosyl iron complexes with thiol-containing ligands. Nitric Oxide 2011; 24:217-23. [DOI: 10.1016/j.niox.2011.04.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 04/14/2011] [Accepted: 04/20/2011] [Indexed: 11/20/2022]
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Tajkarimi K, Burnett AL. The Role of Genital Nerve Afferents in the Physiology of the Sexual Response and Pelvic Floor Function. J Sex Med 2011; 8:1299-312. [DOI: 10.1111/j.1743-6109.2011.02211.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Abstract
INTRODUCTION A role for cytokines in the pathophysiology of erectile dysfunction (ED) has emerged. Cytokines induce genes that synthesize other peptides in the cytokine family and several mediators, such as prostanoids, leukotrienes, nitric oxide, bradykinin, reactive oxygen species, and platelet-activating factor, all of which can affect vascular function. Consistent with the fact that the cavernosal tissue is a complex extension of the vasculature, risk factors that affect the vasculature have been shown to affect cavernosal function as well. Accordingly, the penile tissue has been recognized as an early sentinel for atherosclerosis that underlies coronary artery disease and cardiovascular diseases (CVD). AIM To review the literature pertaining to the role of tumor necrosis factor-alpha (TNF-α) in ED. METHODS PubMed search for pertinent publications on the role of cytokines, particularly TNF-α, in CVD and ED. MAIN OUTCOME MEASURES Clinical and experimental evidence demonstrates that TNF-α may play a role in ED. RESULTS TNF-α has been shown to play an important role in CVD, mainly due to its direct effects on the vasculature. In addition, high levels of TNF-α were demonstrated in patients with ED. In this review, we present a short description of the physiology of erection and the cytokine network. We focus on vascular actions of TNF-α that support a role for this cytokine as a potential candidate in the pathophysiology of ED, particularly in the context of CVD. A brief overview of its discovery, mechanisms of synthesis, receptors, and its main actions on the systemic and penile vasculature is also presented. CONCLUSIONS Considering that ED results from a systemic arterial defect not only confined to the penile vasculature, implication of TNF-α in the pathophysiology of ED offers a humoral linking between CVD and ED.
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Baseline Erectile Function Alters the Cavernous Nerve Quantity and Distribution Around the Prostate. J Urol 2010; 184:2062-7. [DOI: 10.1016/j.juro.2010.06.108] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2010] [Indexed: 11/20/2022]
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OTANI M, YOSHIDA M, MASUNAGA K, NAGATA T, YONO M, HOMMA Y. Neuronal Nitric Oxide Synthase Gene Transfer into the Rat Prostate Using In Vivo Electroporation. Low Urin Tract Symptoms 2010; 2:83-7. [DOI: 10.1111/j.1757-5672.2010.00068.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Awad A, Alsaid B, Bessede T, Droupy S, Benoît G. Evolution in the concept of erection anatomy. Surg Radiol Anat 2010; 33:301-12. [PMID: 20686767 DOI: 10.1007/s00276-010-0707-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Accepted: 07/17/2010] [Indexed: 12/19/2022]
Abstract
PURPOSE To review and to summarize the literature on anatomy and physiology of erection in the past three decades, especially the work done in our institution. METHODS A search of the PubMed database was performed using keywords erection, anatomy and erectile dysfunction (ED). Relevant articles were reviewed, analyzed and summarized. RESULTS Penile vascularisation and innervation vary substantially. Internal pudendal artery is the major source of penile blood supply, but a supralevator accessory pudendal artery that may originate from inferior vesical or obturator or external iliac arteries is not uncommon. Section of this artery during radical prostatectomy (RP) may adversely affect postoperative potency. Anastomoses between the supra and the infralevator arterial pathways are frequent. The cavernous nerves (CNs) contain parasympathetic and sympathetic nerve fibers and these nerves lie within leaves of the lateral endopelvic fascia. Anastomoses between the CNs and the dorsal nerve of the penis are common. Nitric oxide released from noradrenergic, noncholinergic neurotransmission of the CN and from the endothelium is the principal neurotransmitter-mediating penile erection. Interactions between pro-erectile and anti-erectile neurotransmitters are not completely defined. Finally, medial preoptic area and paraventricular nucleus are the key structures in the central control of sexual function and penile erection. CONCLUSIONS The surgical and functional anatomy of erection is complex. Precise knowledge of penile vascularisation and innervation facilitates treatment of ED especially after RP.
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Affiliation(s)
- Ayman Awad
- Laboratory of Experimental Surgery, UPRES 4122, Faculty of Medicine, University Paris-Sud, Le Kremlin Bicêtre, France.
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Dimitriadis F, Karakitsios K, Tsounapi P, Tsambalas S, Loutradis D, Kanakas N, Watanabe NT, Saito M, Miyagawa I, Sofikitis N. Erectile function and male reproduction in men with spinal cord injury: a review. Andrologia 2010; 42:139-65. [DOI: 10.1111/j.1439-0272.2009.00969.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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Nitric oxide neurons and neurotransmission. Prog Neurobiol 2010; 90:246-55. [DOI: 10.1016/j.pneurobio.2009.10.007] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2008] [Revised: 04/22/2009] [Accepted: 10/09/2009] [Indexed: 11/24/2022]
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30
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Pubertal development of penile nitric oxide synthase (NOS)-containing nerve fibers in the rat. AFRICAN JOURNAL OF UROLOGY 2009. [DOI: 10.1007/s12301-009-0043-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Shafik A, Shafik AA, Shafik I, el-Sibai O. URETHRAL SPHINCTERS RESPONSE TO CAVERNOSUS MUSCLES STIMULATION WITH IDENTIFICATION OF CAVERNOSO-URETHRAL REFLEX. ACTA ACUST UNITED AC 2009; 51:335-43. [PMID: 16087561 DOI: 10.1080/014850190944384] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The functional activity of the urethral sphincters during cavernosus muscles' contraction at coitus has been poorly addressed in the literature. We investigated the hypothesis that cavernosus muscles' contraction affects reflex contraction of the urethral sphincters to guard against semen reflux into the urinary bladder or urine leakage from the bladder during orgasm and ejaculation. The electromyographic (EMG) response of the external (EUS) and internal (IUS) urethral sphincters to ischio- (ICM) and bulbo- (BCM) cavernosus muscle stimulation was studied in 15 healthy volunteers (9 men, 6 women, age 39.3 +/- 8.2 SD years). An electrode was applied to each of ICM and BCM (stimulating electrodes) and the 2 urethral sphincters (recording electrodes). The test was repeated after individual anesthetization of the urethral sphincters and the 2 cavernosus muscles, and after using saline instead of lidocaine. Upon stimulation of each of the 2 cavernosus muscles, the EUS and IUS recorded increased EMG activity. Repeated cavernosus muscles' stimulation evoked the urethral sphincteric response without fatigue. The urethral sphincters did not respond to stimulation of the anesthetized cavernosus muscles nor did the anesthetized urethral sphincters respond to cavernosus muscle stimulation. Saline infiltration instead of lidocaine did not affect the urethral sphincteric response to cavernosal muscle stimulation. Results were reproducible. Cavernosus muscles' contraction is suggested to effect EUS and IUS contraction. This action seems to be reflex and mediated through the 'cavernoso-urethral reflex.' Urethral sphincters contraction upon cavernosus muscles contraction during sexual intercourse presumably prevents urine leak from the urinary bladder to urethra, prevents retrograde ejaculation, and propels ejaculate from the posterior to the penile urethra. The cavernoso-urethral reflex can act a diagnostic tool in the investigations of patients with ejaculatory disorders.
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Affiliation(s)
- A Shafik
- Department of Surgery and Experimental Research, Faculty of Medicine, Cairo University, Cairo, Egypt.
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Martin-Alguacil N, Schober J, Kow LM, Pfaff D. Oestrogen receptor expression and neuronal nitric oxide synthase in the clitoris and preputial gland structures of mice. BJU Int 2008; 102:1719-23. [PMID: 18793302 DOI: 10.1111/j.1464-410x.2008.07989.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To study the presence of oestrogen receptors (ER) and neuronal nitric oxide synthase (nNOS) in the mouse clitoris. MATERIALS AND METHODS A series of sections of the pelvic area, including the preputial glands and clitoris, of 10 mice were assessed by immunocytochemical studies specific for ER-alpha and -beta, and nNOS; selected sections were also stained with Masson's trichrome. RESULTS ER alpha was detected in the epithelium of the gland of the clitoris, and in the glandular tissue, preputial and apocrine gland. ER alpha was detected in the nuclei of stromal cells around the cavernous tissue and near the epithelium of the clitoris. Cytoplasm ER alpha was detected in a few cells in an area ventral to the clitoral gland. There was also nuclear staining in the connective tissue cells surrounding the clitoris. Very light ER beta immunostaining was detected in the clitoris and in the tissue related to it. There were some cells with nuclear staining in the vessels of the cavernous tissue of the clitoris. nNOS immunostaining was detected in the clitoris, the preputial gland and the connective tissue. CONCLUSION ER alpha and beta isoforms, and nNOS, are present in the clitoris and preputial glands of female mice in different cellular locations and with differing levels of receptivity. Functional studies would further elucidate the role of receptor functions and their relationship to the neuronal expression of NO.
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Tostes RC, Carneiro FS, Lee AJ, Giachini FRC, Leite R, Osawa Y, Webb RC. Cigarette smoking and erectile dysfunction: focus on NO bioavailability and ROS generation. J Sex Med 2008; 5:1284-95. [PMID: 18331273 DOI: 10.1111/j.1743-6109.2008.00804.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Thirty million men in the United States suffer from erectile dysfunction (ED) and this number is expected to double by 2025. Considered a major public health problem, which seriously affects the quality of life of patients and their partners, ED becomes increasingly prevalent with age and chronic smoking is a major risk factor in the development of ED. AIM To review available evidence concerning the effects of cigarette smoking on vascular changes associated with decreased nitric oxide (NO) bioavailability and increased reactive oxygen species (ROS) generation. METHODS We examined epidemiological and clinical data linking cigarette smoking and ED, and the effects of smoking on vascular NO bioavailability and ROS generation. MAIN OUTCOME MEASURES There are strong parallels between smoking and ED and considerable evidence supporting the concept that smoking-related ED is associated with reduced bioavailability of NO because of increased ROS. RESULTS Cigarette smoking-induced ED in human and animal models is associated with impaired arterial flow to the penis or acute vasospasm of the penile arteries. Long-term smoking produces detrimental effects on the vascular endothelium and peripheral nerves and also causes ultrastructural damage to the corporal tissue, all considered to play a role in chronic smoking-induced ED. Clinical and basic science studies provide strong indirect evidence that smoking may affect penile erection by the impairment of endothelium-dependent smooth muscle relaxation or more specifically by affecting NO production via increased ROS generation. Whether nicotine or other products of cigarette smoke mediate all effects related to vascular damage is still unknown. CONCLUSIONS Smoking prevention represents an important approach for reducing the risk of ED. The characterization of the components of cigarette smoke leading to ED and the mechanisms by which these components alter signaling pathways activated in erectile responses are necessary for a complete comprehension of cigarette smoking-associated ED.
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Affiliation(s)
- Rita C Tostes
- University of Sao Paulo, Department of Pharmacology, Sao Paulo, SP, Brazil.
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Abstract
Penile erection involves a complex interaction between the central nervous system and local factors. It is a neurovascular event modulated by psychological and hormonal factors. The discovery of nitric oxide (NO) as an intercellular messenger or neurotransmitter paved the way for identifying important mechanisms underlying physiological and pathophysiological events in the penis, in addition to providing the knowledge for the development of new therapeutics based on a novel concept of molecule and cell interaction. Despite the fact that sinusoidal endothelial cells also produce and release NO in response to chemical and possibly physical stimuli, roles of neurogenic NO in penile erection appear to be more attractive and convincing, since the pharmacological neuromodulation represents an essential step to attaining penile erection. Erectile dysfunction (ED) is caused by a variety of pathogenic factors, particularly impaired formation and action of NO. Hence, a thorough knowledge of the physiology of erection is essential for future pharmacological innovations in the field of male ED, particularly targeting NO or intracellular cyclic GMP, which represent the most promising therapeutic approach to treat patients with ED.
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Affiliation(s)
- Fernanda B M Priviero
- Department of Physiology, Medical College of Georgia, 1120 15th Street, CA 3101 Augusta, GA 30912-3000, USA.
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Shafik A, Shafik IA, Sibai OE, Shafik AA. The effect of external urethral sphincter contraction on the cavernosus muscles and its role in the sexual act. Int Urol Nephrol 2007; 39:541-6. [PMID: 17310309 DOI: 10.1007/s11255-006-9081-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Accepted: 06/27/2006] [Indexed: 11/26/2022]
Abstract
OBJECTIVES/AIM A study of the effect of external urethral sphincter contraction on ischio-/bulbo-cavernosus muscles could not be traced in the literature. We investigated the hypothesis that external urethral sphincter contraction induces cavernosus muscles' contraction. METHODS Twenty-one healthy volunteers (age 37.6 +/- 9.7 SD years, 12 men, nine women) were studied. The electromyographic response of the ischio- and bulbo-cavernosus muscles to external urethral sphincter stimulation was recorded before and after anesthetization of the external urethral sphincter, and the ischio- and bulbo-cavernosus muscles; the response was also recorded using normal saline instead of lidocaine. RESULTS Upon external urethral sphincter stimulation (five square pulses, 1 ms duration, 53.8 +/- 10.2 mA threshold), both cavernosus muscles exhibited increased electromyographic activity with a mean amplitude of 386.2 +/- 44.9 microV for the ischio-cavernosus and 318.4 +/- 36.6 microV for the bulbo-cavernosus muscle. The mean latency read 16.8 +/- 1.3 ms for the ischio-cavernosus muscle and 15.7 +/- 1.2 ms for the bulbo-cavernosus muscle. Neither the ischio- nor the bulbo-cavernosus muscle responded to stimulation of the anesthetized external urethral sphincter, but both responded after saline administration. Likewise, the anesthetized ischio- and bulbo-cavernosus muscles showed no response to external urethral sphincter stimulation but responded after saline had been injected. CONCLUSIONS Increased electromyographic activity of the two cavernosus muscles on external urethral sphincter stimulation presumably denotes contraction of these two muscles and that this action is probably reflex, mediated through the 'sphinctero-cavernosus-reflex'. Cavernosus muscles' contraction assists in the erectile and ejaculatory mechanisms. It is suggested that this reflex be included as an investigative tool in the diagnosis of erectile and ejaculatory disorders, provided further studies are performed.
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Affiliation(s)
- Ahmed Shafik
- Department of Surgery and Experimental Research, Faculty of Medicine, Cairo University, Cairo, Egypt.
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Kendirci M, Teloken PE, Champion HC, Hellstrom WJG, Bivalacqua TJ. Gene Therapy for Erectile Dysfunction: Fact or Fiction? Eur Urol 2006; 50:1208-22. [PMID: 16950560 DOI: 10.1016/j.eururo.2006.08.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2006] [Accepted: 08/02/2006] [Indexed: 01/12/2023]
Abstract
OBJECTIVES Erectile dysfunction (ED) is a major health problem that seriously affects the quality of life of patients and their partners. Although all three selective phosphodiesterase type 5 inhibitors (PDE5-Is) are effective in the majority of ED cases, PDE5-I therapy is less efficacious in some hard-to-treat populations (diabetics, men after radical prostatectomy), prompting the development of new approaches, including gene therapy strategies for ED. METHODS Gene therapy approaches are discussed in terms of the possible role of gene therapy for the treatment of ED, potential targets for gene transfer, vectors to carry targeted genes, and gene strategies for ED in certain disease states, such as diabetes, ageing, arterial and venogenic insufficiency, and cavernous nerve injury. RESULTS The penis is a convenient tissue target for gene therapy because of its external location and accessibility, the ubiquity of endothelial-lined spaces, and low level of blood flow, especially in the flaccid state. Gene therapy approaches have focused on a number of signaling pathways that are crucial for penile erection, such as nitric oxide/cyclic guanosine monophosphate, RhoA/Rho-kinase, growth factors, ion channels, peptides, and control of oxidative stress. CONCLUSIONS The need for effective ED therapies in difficult-to-treat patients has encouraged investigators to seek novel modalities for the treatment of ED. Recent preclinical and clinical trials have demonstrated that gene therapy strategies may be feasible for these purposes.
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Affiliation(s)
- Muammer Kendirci
- Department of Urology, Sisli Etfal Training and Research Hospital, Istanbul, Turkey
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Burnett AL. Nitric oxide in the penis--science and therapeutic implications from erectile dysfunction to priapism. J Sex Med 2006; 3:578-582. [PMID: 16839312 DOI: 10.1111/j.1743-6109.2006.00270.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Arthur L Burnett
- Department of Urology, The James Buchanan Brady Urological Institute, The Johns Hopkins Hospital and The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Morelli A, Filippi S, Vignozzi L, Mancina R, Maggi M. Physiology of Erectile Function: An Update on Intracellular Molecular Processes. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.eeus.2006.03.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Sáenz de Tejada I, Angulo J, Cellek S, González-Cadavid N, Heaton J, Pickard R, Simonsen U. Physiology of erectile function. J Sex Med 2006; 1:254-65. [PMID: 16422955 DOI: 10.1111/j.1743-6109.04038.x] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
INTRODUCTION There are numerous investigations concerning the balance and interactions between relaxant and contractile factors regulating penile smooth muscle (arterial and trabecular) tone, the determinant of penile flaccidity or erection. Enhanced knowledge of erectile physiology may improve management of men with erectile dysfunction. Aim. To provide state-of-the-art knowledge on the physiology of erectile function. METHODS An international consultation in collaboration with the major urology and sexual medicine associations assembled over 200 multidisciplinary experts from 60 countries into 17 committees. Committee members established specific objectives and scopes for various male and female sexual medicine topics. The recommendations concerning state-of-the-art knowledge in the respective sexual medicine topic represent the opinion of experts from five continents developed in a process over a two-year period. Concerning the physiology of erectile function and pathophysiology of erectile dysfunction committee, there were seven experts from five countries. MAIN OUTCOME MEASURE Expert opinion was based on the grading of evidence-based medical literature, widespread internal committee discussion, public presentation, and debate. RESULTS Key roles in the mechanism determining the tone of penile smooth muscle are played by the rise of the intracellular concentration of free calcium and the sensitivity of the contractile machinery to calcium, endothelial health, endothelium-derived nitric oxide, endothelium-derived hyperpolarizing factor (EDHF), neuronal nitric oxide, cyclic guanosine monophosphate-dependent protein kinase and phosphodiesterase type 5. CONCLUSIONS A number of new mechanisms have been identified for the local regulation of penile smooth muscle contractility and therefore penile erection. Molecules participating in these pathways can be considered targets for the development of new treatments to treat erectile dysfunction.
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Hurt KJ, Sezen SF, Champion HC, Crone JK, Palese MA, Huang PL, Sawa A, Luo X, Musicki B, Snyder SH, Burnett AL. Alternatively spliced neuronal nitric oxide synthase mediates penile erection. Proc Natl Acad Sci U S A 2006; 103:3440-3. [PMID: 16488973 PMCID: PMC1413936 DOI: 10.1073/pnas.0511326103] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A key role for nitric oxide (NO) in penile erection is well established, but the relative roles of the neuronal NO synthase (nNOS) versus endothelial forms of NOS are not clear. nNOS- and endothelial NOS-deficient mice maintain erectile function and reproductive capacity, questioning the importance of NO. Alternatively, residual NO produced by shorter transcripts in the nNOS(-/-) animals might suffice for normal physiologic function. We show that the beta splice variant of nNOS elicits normal erection despite a decrease in stimulus-response characteristics and a 5-fold increased sensitivity to the NOS inhibitor, l-NAME. Residual nNOSbeta generates only 10% of the normal NO level in vitro but produces citrulline and diaphorase staining reflecting in vivo NOS activity in pelvic ganglion nerves that is comparable to WT animals. Thus, alternatively spliced forms of nNOS are major mediators of penile erection and so may be targets for therapeutic intervention.
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Affiliation(s)
| | | | | | | | | | - Paul L. Huang
- Cardiovascular Research Center and Cardiology Division, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129
| | - Akira Sawa
- Cellular and Molecular Medicine
- *Neuroscience
- Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205; and
| | | | | | - Solomon H. Snyder
- *Neuroscience
- **Pharmacology and Molecular Sciences, and
- Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205; and
- To whom correspondence may be addressed.
E-mail: or
| | - Arthur L. Burnett
- Departments of Urology and
- To whom correspondence may be addressed.
E-mail: or
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Abstract
This article reviews the physiology of penile erection, the components of erectile function, and the pathophysiology of erectile dysfunction. The molecular and clinical under-standing of erectile function continues to gain ground at a particularly fast rate. Advances in gene discovery have aided greatly in working knowledge of smooth muscle relaxation/contraction pathways. The understanding of the nitric oxide pathway has aided not only in the molecular understanding of the tumescence but also greatly in the therapy of erectile dysfunction.
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Affiliation(s)
- Robert C. Dean
- Clinical Fellow, Department of Urology, University of California, San Francisco Medical Center, San Francisco, California; and
| | - Tom F. Lue
- Professor and Vice-Chair, Department of Urology, University of California, San Francisco Medical Center, San Francisco, California
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McLaughlin PW, Troyer S, Berri S, Narayana V, Meirowitz A, Roberson PL, Montie J. Functional anatomy of the prostate: implications for treatment planning. Int J Radiat Oncol Biol Phys 2005; 63:479-91. [PMID: 16168840 DOI: 10.1016/j.ijrobp.2005.02.036] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2005] [Revised: 02/09/2005] [Accepted: 02/15/2005] [Indexed: 11/28/2022]
Abstract
PURPOSE To summarize the functional anatomy relevant to prostate cancer treatment planning. METHODS AND MATERIALS Coronal, axial, and sagittal T2 magnetic resonance imaging (MRI) and MRI angiography were fused by mutual information and registered with computed tomography (CT) scan data sets to improve definition of zonal anatomy of the prostate and critical adjacent structures. RESULTS The three major prostate zones (inner, outer, and anterior fibromuscular) are visible by T2 MRI imaging. The bladder, bladder neck, and internal (preprostatic) sphincter are a continuous muscular structure and clear definition of the preprostatic sphincter is difficult by MRI. Transition zone hypertrophy may efface the bladder neck and internal sphincter. The external "lower" sphincter is clearly visible by T2 MRI with wide variations in length. The critical erectile structures are the internal pudendal artery (defined by MRI angiogram or T2 MRI), corpus cavernosum, and neurovascular bundle. The neurovascular bundle is visible along the posterior lateral surface of the prostate on CT and MRI, but its terminal branches (cavernosal nerves) are not visible and must be defined by their relationship to the urethra within the genitourinary diaphragm. Visualization of the ejaculatory ducts within the prostate is possible on sagittal MRI. The anatomy of the prostate-rectum interface is clarified by MRI, as is the potentially important distinction of rectal muscle and rectal mucosa. CONCLUSION Improved understanding of functional anatomy and imaging of the prostate and critical adjacent structures will improve prostate radiation therapy by improvement of dose and toxicity correlation, limitation of dose to critical structures, and potential improvement in post therapy quality of life.
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Ozakman S, Uma S. The effects of superoxide anion generators on responses to exogenous nitric oxide and non-adrenergic, non-cholinergic nerve stimulation in rat isolated penile bulb. Basic Clin Pharmacol Toxicol 2005; 97:179-84. [PMID: 16128913 DOI: 10.1111/j.1742-7843.2005.pto_973112.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The effects of the superoxide anion generators, pyrogallol and hydroquinone on relaxations induced by electrical field stimulation (70 V, 0.7 msec., 0.5-8 Hz for 5 sec.) and exogenous nitric oxide donor sodium nitroprusside, were investigated in rat penile bulb precontracted with phenylephrine (10(-4) M). Pyrogallol (10(-4) M, 3 x 10(-4) M) and hydroquinone (3 x 10(-4) M) reduced the relaxations induced by sodium nitroprusside, but had no effect on relaxations elicited by nitrergic nerve stimulation. After treatment with diethyldithiocarbamate (3 x 10(-3) M), an inhibitor of Cu/Zn superoxide dismutase, both agents reduced the relaxations induced by electrical field stimulation. Superoxide dismutase, at 300 U/ml, significantly reversed the inhibitory action of pyrogallol and hydroquinone on responses to sodium nitroprusside. This concentration of superoxide dismutase failed to reverse the inhibitory action of pyrogallol on responses to electrical field stimulation observed in the presence of diethyldithiocarbamate, while at 600 U/ml it significantly prevented the reduction in relaxations. However, even at 600 U/ml, superoxide dismutase did not alter the decrease in responses to electrical field stimulation evoked by hydroquinone in tissues pretreated with diethyldithiocarbamate. These results suggest that the nitrergic transmitter in rat penile bulb is protected against superoxide anions by endogenous Cu/Zn superoxide dismutase in a manner similar to gastric fundus and anococcygeus muscles.
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Affiliation(s)
- Selda Ozakman
- Department of Pharmacology, Faculty of Pharmacy, Hacettepe University, 06100, Sihhiye, Ankara, Turkey
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Hallén K, Gustafsson LE, Wiklund NP. Nerve-induced release of nitric oxide from the rabbit corpus cavernosum is modulated by cyclic guanosine 3',5'-monophosphate. Neuroscience 2005; 133:169-74. [PMID: 15893640 DOI: 10.1016/j.neuroscience.2005.02.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2004] [Revised: 01/30/2005] [Accepted: 02/06/2005] [Indexed: 11/16/2022]
Abstract
Nitric oxide (NO) is a neurotransmitter of the autonomic nerves in the urogenital tract, in particular the release of NO in the cavernous tissue is of importance for maintaining erection. However, the regulation of NO formation in neurons of the corpus cavernosum is poorly understood. Here, we report, that upon electrical stimulation of isolated rabbit corpus cavernosum, NO/NO(2-) was formed and released in a reproducible fashion. The NO synthase inhibitor N(omega)-nitro-L-arginine methyl ester decreased the amount of NO/NO(2-) released to 50+/-18% (P<0.05). The neurotoxin tetrodotoxin diminished the nerve-induced release of NO/NO(2-), to 35+/-10% (P<0.001). Blockage of the cholinergic and noradrenergic pathways by application of scopolamine and guanethidin (both 10(-5) M) did not alter the basal or nerve-evoked formation of NO/NO(2-). We also applied modulators of the soluble guanylate cyclase (sGC)/cyclic guanosine 3',5'-monophosphate (cGMP) pathway to study if and to what extent cGMP might affect the release of NO from the erectile tissue. In the presence of the cGMP analog 8-Br-cGMP (10(-4) M), and, the sGC stimulator 3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole (10(-4) M), the release of NO/NO(2-) was increased to 385+/-120% (P<0.05) and 282+/-78% (P<0.05), respectively. The effect of the phosphodiesterase inhibitor zaprinast (10(-4) M), was not significant (209+/-53%, n.s). In contrast, inhibition of sGC by 1-H-[1,2,4]oxadiazole[4,3-a]quinoxalin-1-one (10(-5) M) decreased the release of NO/NO(2-) to 64+/-14% (P<0.05). Our results suggest that NO/NO(2-) is released by nitrergic neurons within the rabbit corpus cavernosum and that the release is subject to modulation by the sGC/cGMP pathway, but not to modulation by acetylcholine or noradrenaline.
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Affiliation(s)
- K Hallén
- Department of Surgical Science, Section of Urology, Karolinska Institutet, 171 76 Stockholm, Sweden.
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Aziz MTA, El-Asmar MF, Mostafa T, Atta H, Wassef MAA, Fouad HH, Roshdy NK, Rashed LA, Sabry D. Effects of Nitric Oxide Synthase and Heme Oxygenase Inducers and Inhibitors on Molecular Signaling of Erectile Function. J Clin Biochem Nutr 2005. [DOI: 10.3164/jcbn.37.103] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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Bochinski D, Hsieh PS, Nunes L, Lin GT, Lin CS, Spencer EM, Lue TF. Effect of insulin-like growth factor-1 and insulin-like growth factor binding protein-3 complex in cavernous nerve cryoablation. Int J Impot Res 2004; 16:418-23. [PMID: 14973525 DOI: 10.1038/sj.ijir.3901190] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The purpose of this work was to study the effect of insulin-like growth factor 1 (IGF-1) and its binding protein (IGFBP-3) on the recovery of erectile function in a rat model for neurogenic impotence. In all, 28 male Sprague-Dawley rats were divided into four groups: seven underwent a sham operation; seven underwent bilateral cavernous nerve freezing (control group); seven underwent bilateral cavernous nerve freezing followed by intraperitoneal injection of IGF-1; and seven underwent bilateral cavernous nerve freezing followed by intraperitoneal injection of IGFBP-3. Erectile response was assessed by cavernous nerve electrostimulation at 3 months, and samples of penile tissue were evaluated histochemically for nitric oxide synthase (NOS)-containing fibers. In the sham and IGF-1 group, there were significantly higher maximal intracavernous pressures compared to the IGFBP-3 complex and the control group. Correspondingly in the cavernosum, there were significantly more NOS-containing nerve fibers in the sham and IGF-1 groups. In conclusion, administration of IGF-1 can facilitate the regeneration of NOS-containing nerve fibers in penile tissue and enhance the recovery of erectile function after bilateral cavernous nerve cryoablation. The reverse effect was noted with the IGFBP-3 complex injection.
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Affiliation(s)
- D Bochinski
- Department of Urology, School of Medicine, University of California, San Francisco, California 94143-0738, USA
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Fernandes de Oliveira J, Teixeira CE, Arantes EC, de Nucci G, Antunes E. Relaxation of rabbit corpus cavernosum by selective activators of voltage-gated sodium channels: role of nitric oxide-cyclic guanosine monophosphate pathway. Urology 2003; 62:581-8. [PMID: 12946781 DOI: 10.1016/s0090-4295(03)00462-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES To investigate the capacity of voltage-gated Na(+) channel activators such as batrachotoxin, aconitine, veratridine, Ts1 (formerly Tityus gamma-toxin), and brevetoxin-3 to induce relaxation of rabbit isolated corpus cavernosum (RbCC) and the pharmacologic mechanisms underlying this phenomenon. The voltage-gated Na(+) channels of the corpus cavernosum are essential for erectile function. A number of biologic toxins exert their effects by modifying the properties of these channels. METHODS Male New Zealand white rabbits were anesthetized with pentobarbital sodium. Strips of RbCC were transferred to 10-mL organ baths containing oxygenated and warmed Krebs solution. The RbCC strips were connected to force-displacement transducers, and changes in isometric force were recorded using a PowerLab 400 data acquisition system. Corporeal smooth muscle was precontracted submaximally with phenylephrine (10 micromol/L). RESULTS The binding site-2 (batrachotoxin, aconitine, and veratridine) and binding site-5 (brevetoxin-3) voltage-gated Na(+) channel activators caused slow-onset RbCC relaxations, and the binding site-4 activator Ts1 produced transitory relaxations followed by a return to baseline. The Na(+)channel blockers tetrodotoxin and saxitoxin (0.1 micromol/L each) abolished the relaxations induced by these agonists. Similarly, the nitric oxide synthase inhibitor N(omega)-nitro-l-arginine methyl ester (100 micromol/L) markedly reduced the relaxations and l-arginine (1 mmol/L) restored the relaxations. The soluble guanylyl cyclase inhibitor 1H-[1,2,4] oxidiazolo[4,3-alpha] quinoxalin-1-one (10 micromol/L) reduced the relaxations, and the phosphodiesterase type 5 inhibitor sildenafil (100 nmol/L) significantly potentiated the relaxations by all activators. CONCLUSIONS Our results indicate that the relaxations evoked by selective activators of voltage-gated Na(+) channels are mediated by the release of nitric oxide from nitrergic nerves and the activation of the nitric oxide-cyclic guanosine monophosphate pathway in the smooth muscle cells of erectile tissue.
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Toda N, Okamura T. The pharmacology of nitric oxide in the peripheral nervous system of blood vessels. Pharmacol Rev 2003; 55:271-324. [PMID: 12773630 DOI: 10.1124/pr.55.2.3] [Citation(s) in RCA: 221] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Unanticipated, novel hypothesis on nitric oxide (NO) radical, an inorganic, labile, gaseous molecule, as a neurotransmitter first appeared in late 1989 and into the early 1990s, and solid evidences supporting this idea have been accumulated during the last decade of the 20th century. The discovery of nitrergic innervation of vascular smooth muscle has led to a new understanding of the neurogenic control of vascular function. Physiological roles of the nitrergic nerve in vascular smooth muscle include the dominant vasodilator control of cerebral and ocular arteries, the reciprocal regulation with the adrenergic vasoconstrictor nerve in other arteries and veins, and in the initiation and maintenance of penile erection in association with smooth muscle relaxation of the corpus cavernosum. The discovery of autonomic efferent nerves in which NO plays key roles as a neurotransmitter in blood vessels, the physiological roles of this nerve in the control of smooth muscle tone of the artery, vein, and corpus cavernosum, and pharmacological and pathological implications of neurogenic NO have been reviewed. This nerve is a postganglionic parasympathetic nerve. Mechanical responses to stimulation of the nerve, mainly mediated by NO, clearly differ from those to cholinergic nerve stimulation. The naming "nitrergic or nitroxidergic" is therefore proposed to avoid confusion of the term "cholinergic nerve", from which acetylcholine is released as a major neurotransmitter. By establishing functional roles of nitrergic, cholinergic, adrenergic, and other autonomic efferent nerves in the regulation of vascular tone and the interactions of these nerves in vivo, especially in humans, progress in the understanding of cardiovascular dysfunctions and the development of pharmacotherapeutic strategies would be expected in the future.
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Affiliation(s)
- Noboru Toda
- Toyama Institute for Cardiovascular Pharmacology Research, Toyama Bldg., 7-13, 1-Chome, Azuchi-machi, Chuo-ku, Osaka 541-0052, Japan.
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Filippi S, Crescioli C, Vannelli GB, Fazzini A, Natali A, Riffaud JP, Maggi M, Ledda F. Effects of NCX 4050, a new NO donor, in rabbit and human corpus cavernosum. INTERNATIONAL JOURNAL OF ANDROLOGY 2003; 26:101-8. [PMID: 12641828 DOI: 10.1046/j.1365-2605.2003.00403.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The effects of NCX 4050, a drug belonging to a new class of NO donors, was investigated in isolated preparations of human and rabbit corpus cavernosum (CC) and in human foetal corpora cavernosa (hfCC) smooth muscle cells. In strips of rabbit CC, NCX 4050 (0.001-100 microM) induced a concentration-dependent relaxation which was influenced neither by Nw-nitro-l-arginine-methyl-ester (l-NAME; 100 microm) nor by endothelium deprivation. The NCX 4050-induced relaxation was significantly reduced by the guanylate cyclase inhibitor 1H-[1,2,4]-oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 1 microm) and enhanced by a specific phosphodiesterase 5 inhibitor, sildenafil (300 nm). Moreover, NCX 4050 (0.01-1 microm), induced a concentration-dependent potentiation of the relaxant response induced by electrical field stimulation (EFS) in rabbit preparations pre-treated with guanethidine and indomethacin. The relaxant effect of NCX 4050 was similar to that obtained by increasing concentrations (0.001-100 microm) of sodium nitroprusside (SNP) in either rabbit or human preparations. To further investigate the activity of NCX 4050 on human corpora cavernosa, we exposed cultured hfCC smooth muscle cells to increasing concentrations of NCX 4050 and SNP. We found that both compounds dose-dependently reduced cell proliferation. The antiproliferative effect of all the concentration tested of NCX 4050 was completely blocked by ODQ (1 microm). These results suggest that in rabbit and human corpora cavernosa NCX 4050 acts by activating guanylate cyclase activity, induces smooth muscle relaxation and quiescence. Our results provide a rationale for a possible future use of NCX 4050 in the pharmacotherapy of erectile dysfunction linked to an impaired release of NO from the endothelium.
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Affiliation(s)
- S Filippi
- Department of Preclinical and Clinical Pharmacology, University of Florence, Florence, Italy
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Abstract
The therapeutic modulation of the nitric oxide (NO) system has generated considerable interest as a new way for managing many disease processes. In stroke, a useful strategy is to increase NO availability and thereby exploit its beneficial antiplatelet, antiatherosclerotic, haemodynamic and neuroprotective properties. Pharmacologically, this can be achieved by providing NO substrate, using NO donors or by upregulating nitric oxide synthase. Alternatively, one can reduce NO availability by inhibiting NO synthase and thereby limiting its pro-inflammatory and neurotoxic properties. This article reviews developments in NO-related therapeutics for treatment of stroke, with a particular emphasis on compounds that are in the clinical research and development pipeline. Although the routine use of NO therapeutics for the prevention or treatment of stroke cannot currently be recommended, we are evidently at an exciting stage in their pharmacological development. Definitive randomised controlled trials in stroke patients are required as a matter of urgency.
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Affiliation(s)
- M R Willmot
- Division of Stroke Medicine, Clinical Sciences Building, University of Nottingham, Nottingham NG5 1PB, UK
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