Dysfunctional penile cholinergic nerves in diabetic impotent men

Metabolic Syndrome and Male Fertility

Metabolic syndrome (MetS) represents a cluster of conditions that have a negative impact on human health overall. Its prevalence has been rapidly increasing worldwide and has coincided with a global decrease in birth rates and fertility potential. This review aims to address this observation through studying the relationship between MetS and male reproductive health. The effects of obesity, dyslipidemia, hypertension, and insulin resistance on male fertility were examined and supporting evidence explaining the pathophysiology of sperm dysfunction with each MetS component were described. Adopting a healthy lifestyle appears to be the single most important intervention to prevent the unwanted effects of MetS on men's health and fertility. Further studies addressing the components of MetS and their impact on male reproduction are required to enhance our understanding of the underlying pathophysiology and to propose new methods for therapeutic intervention.

Chronic treatment with a type 5 phosphodiesterase inhibitor suppresses apoptosis of corporal smooth muscle by potentiating Akt signalling in a rat model of diabetic erectile dysfunction

OBJECTIVES

To examine whether chronic treatment with a type 5 phosphodiesterase inhibitor (PDE5I) could suppress corporal apoptosis via potentiation of Akt signalling in diabetic erectile dysfunction.

METHODS

Sprague-Dawley rats (12 wk old) were divided into three groups (n=12 in each): normal control, diabetes (DM), and diabetes treated with PDE5I (DM+PDE5I). The rats in the diabetic groups received a single injection of streptozotocin (50mg/kg), and from 8 wk after establishment of diabetes, DM and DM+PDE5I were treated with vehicle and PDE5I (SK-3530, 10mg/kg), respectively, for 4 wk. After 12 wk of streptozotocin injections, six rats in each group underwent cavernosometry with cavernous nerve electrostimulation (2V, 0.2 ms, 50s, 2.5-20 Hz). The penile tissues from the remaining six rats were used for immunohistochemical evaluation of apoptosis, immunoblotting for the phosphorylation of Akt and its downstream molecule Bad, and a colorimetric assay of caspase activity.

RESULTS

Rats in the DM group showed markedly lower erectile parameters than those in the control group, whereas rats in the DM+PDE5I group showed normalized results. Despite persistent hyperglycaemia, PDE5I treatment significantly reduced the mean apoptotic index (39.6+/-4.6 vs. 21.3+/-1.7, p<0.05). Densitometry revealed significantly higher levels of Akt and Bad phosphorylation, implying inhibition of pro-apoptotic stimuli. PDE5I treatment also significantly inhibited the activities of cavernosal caspase 3 and caspase 9, the main effectors of apoptosis.

CONCLUSIONS

Chronic treatment with PDE5I activated Akt signalling, which suppressed pro-apoptotic stimuli and maintained erectile function in rat model of diabetic erectile dysfunction.

Adenosine actions are preserved in corpus cavernosum from obese and type II diabetic db/db mouse

INTRODUCTION

Erectile dysfunction (ED) in diabetes is associated with autonomic neuropathy and endothelial dysfunction. Whereas the nonadrenergic-noncholinergic (NANC)/neurogenic nitric oxide pathway has received great attention in diabetes-associated ED, few studies have addressed sympathetic overactivity.

AIM

To test the hypothesis that adenosine-induced inhibition of adrenergic-mediated contractile responses in mouse corpus cavernosum is impaired in the presence of diabetes.

METHODS

The db/db (obesity and type II diabetes caused by a leptin receptor mutation) mouse strain was used as a model of obesity and type II diabetes, and standard procedures were performed to evaluate functional cavernosal responses.

MAIN OUTCOME MEASURES

Increased cavernosal responses to sympathetic stimulation in db/db mice are not associated with impaired prejunctional actions of adenosine.

RESULTS

Electrical field stimulation (EFS)-, but not phenylephrine (PE)-, induced contractions are enhanced in cavernosal strips from db/db mice in comparison with those from lean littermates. Direct effects of adenosine, 2-chloro-adenosine, A(1) receptor agonist C-8031 (N6 cyclopentyladenosine), and sodium nitroprusside are similar between the strips from lean and db/db mice, whereas relaxant responses to acetylcholine and NANC stimulation are significantly impaired in the cavernosal strips from db/db mice. 5'-Iodotubercidin (adenosine kinase inhibitor) and dipyridamole (inhibitor of adenosine transport), as well as the A(1) agonist C-8031, significantly and similarly inhibit contractions induced by stimulation of adrenergic nerves in the cavernosal strips from lean and db/db mice.

CONCLUSIONS

Results from this study suggest that corpora cavernosa from obese and diabetic db/db mice display altered neural-mediated responses that would favor penile detumescence, i.e., increased contractile response to adrenergic nerve stimulation and decreased relaxant responses upon activation of NANC nerves. However, increased cavernosal responses to adrenergic nerve stimulation are not due to impaired negative modulation of sympathetic neurotransmission by adenosine in this diabetic model.

Pharmacology of erectile dysfunction in man

Erectile dysfunction (ED) is defined as the consistent or recurrent inability of a man to attain and/or maintain a penile erection sufficient for sexual activity (2nd International Consultation on Sexual Dysfunction-Paris, June 28th-July 1st, 2003). Following the discovery and introduction 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 5 years. This review is structured in order to give the reader an overview of the clinical and preclinical data available on the peripheral regulation of and the mediators involved in human penile erection. The most widely accepted risk factors for ED are discussed. The article is focused on human data, and the safety and effectiveness of the 3 commercially available Phosphodiesterase-5 (PDE5) inhibitors used to treat ED are also discussed.

Linking erectile dysfunction and coronary artery disease

Coronary artery disease (CAD) and erectile dysfunction (ED) are both highly prevalent conditions that frequently coexist. Additionally, they share mutual vascular risk factors, suggesting that they are both manifestations of systemic vascular disease. The role of endothelial dysfunction in CAD is well established. Normal erectile function is primarily a vascular event that relies heavily on endothelially derived, nitric oxide-induced vasodilation. Accordingly, endothelial dysfunction appears to be a common pathological etiology and mechanism of disease progression between CAD and ED. The risk factors of diabetes mellitus, hypertension, hyperlipidemia, obesity and tobacco abuse contribute to endothelial dysfunction. This article reviews the role of vascular endothelium in health, the abnormalities resulting from vascular risk factors, and clinical trials evaluating the role of endothelial dysfunction in ED.

Oxidative stress and antioxidant therapy: their impact in diabetes-associated erectile dysfunction

Oxidative stress is believed to affect the development of diabetic-associated vasculopathy, endothelial dysfunction, and neuropathy within erectile tissue. Our hypothesis is that, given adequate concentrations of the oxygen free radical scavenger vitamin E, enhanced levels of circulating nitric oxide (NO) should improve erectile function with the potential for a synergistic effect with a phosphodiesterase type 5 (PDE5) inhibitor. Twenty adult male Sprague-Dawley streptozotocin-induced (60 mg/kg intraperitoneally) diabetic rats were placed in 4 therapeutic groups (n = 5 per group) as follows: 1) peanut oil only (diabetic control), 2) 20 IU of vitamin E per day, 3) 5 mg/kg of sildenafil per day, and 4) vitamin E plus sildenafil using oral gavage for 3 weeks. In addition, 5 age-matched rats served as normal nondiabetic controls (normal). Erectile function was assessed by measuring the rise in intracavernous pressure (ICP) following cavernous nerve electrostimulation. Penile tissue was evaluated for neuronal NO synthase (nNOS), smooth muscle alpha-actin, nitrotyrosine, and endothelial cell integrity. Urine nitrite and nitrate (NOx) concentration was quantified, and electrolytes were tested by a serum biochemistry panel. A significant decrease in ICP was recorded in the diabetic animals, with improvement measured in the animals receiving PDE5 inhibitors either with or without vitamin E; the controls had a pressure of 54.8 +/- 5.3 cm H2O, the vitamin E group had a pressure of 73.5 +/- 6.6 cm H2O, the sildenafil group had a pressure of 78.4 +/- 10.77 cm H2O, and the vitamin E plus sildenafil group had a pressure of 87.9 +/- 5.5 cm H2O (P <.05), compared with the normal cohorts at 103.0 +/- 4.8 cm H2O. Histoexaminations showed improved nNOS, endothelial cell, and smooth muscle cell staining in the vitamin E plus sildenafil group compared to the control animals. Urine NOx increased significantly in all the diabetic groups but was blunted in the vitamin E and vitamin E plus sildenafil groups. A significant increase in positive staining for nitrotyrosine was observed in the vitamin E plus sildenafil group. Vitamin E enhanced the therapeutic effect of the PDE5 inhibitor in this study, supporting the potential use of oxygen free radical scavengers in salvaging erectile function in diabetic patients.

Insulin regulates neuronal M2 muscarinic receptor function in the ileum of diabetic rats

Acetylcholine release from cholinergic nerves in the gastrointestinal tract is limited by neuronal M(2) muscarinic receptors. In diabetic animals, M(2) muscarinic receptor function in the ileum is increased, leading to decreased acetylcholine release and smooth muscle contraction in response to nerve stimulation. The mechanisms responsible for increased M(2) muscarinic receptor function are unknown but may contribute to the gastrointestinal dysmotility that occurs frequently in diabetics. In this study, we investigated whether insulin modulates M(2) muscarinic receptor function in the gastrointestinal tract of diabetic rats. M(2) muscarinic receptor function was tested by measuring the ability of an agonist, pilocarpine, to inhibit and an antagonist, methoctramine, to potentiate electrical field stimulation (EFS)-induced contraction of ileum in vitro. Insulin administration (0.2, 0.6, and 2 U s.c. daily for 7 days) reversed the diabetes-induced increase in M(2) muscarinic receptor function and restored normal contractions to EFS. Insulin had no effect on the function of postjunctional M(3) muscarinic receptors, determined by measuring contractile responses to acetylcholine. These data suggest that insulin tonically inhibits neuronal M(2) muscarinic receptors. Thus, loss of insulin removes this inhibition and increases M(2) muscarinic receptor function leading to decreased acetylcholine release and contraction to EFS. In nondiabetic rats, there was a trend that higher insulin doses (0.6 and 2 U) increased M(2) muscarinic receptor function, suggesting a bell-shaped concentration-response relationship for insulin. In conclusion, lack of insulin or excess insulin increases M(2) muscarinic receptor function in rat ileum. This mechanism may contribute to decreased acetylcholine release in the gastrointestinal tract of diabetics, resulting in dysmotility.

Brain nitric oxides synthase in major pelvic ganglia of aged (LETO) and diabetic (OLETF) rats

This study was conducted to evaluate the effects of aging and diabetes mellitus (DM) on brain nitric oxide synthase (bNOS) expression in major pelvic ganglia (MPG) of rats. Otsuka Long Evans Tokushima Fatty rats (12, 30, and 70 weeks old), which are genetic models with non-insulin-dependent DM (NIDDM), and age-matched nondiabetic Long Evans Tokushima Otsuka controls were used. The MPG of all rats in this study were subjected to cryo-sectioning and staining with bNOS polyclonal AB and rhodamine-conjugated rabbit IgG. Fluorescence intensities of the stained neurons were assessed in randomly selected fields per each specimen. Animals of both groups revealed significant decline in the staining intensity of their neurons with aging and the progress of DM, but diabetic rats showed more decline than controls. In conclusion, both aging and NIDDM could decrease bNOS expression in rat MPG. However, NIDDM has a more evident effect than aging on that expression. The decrease in bNOS may cause a disturbance in functions of the target pelvic structures of these ganglia under both conditions.

Neurogenic erectile dysfunction

Penile erection is a neurovascular event modulated by psyche and hormones. Erectile dysfunction (ED) has been classified as psychogenic, arteriogenic, neurogenic, endocrinologic, and cavernosal, based on the organs that are involved in penile erection. Among these types, neurogenic ED may be the most common, probably because a deficiency of neurotransmitters is the final common pathway in many diseases and conditions. This review discusses the physiology, pathophysiology, diagnosis, and treatment of erectile function and dysfunction, as well as strategies for future research.

The effect of sildenafil on corpus cavernosal smooth muscle relaxation and cyclic GMP formation in the diabetic rabbit

Sildenafil, a type V phosphodiesterase inhibitor, enhances smooth muscle relaxation in normal human and rabbit corpus cavernosum. We investigated the in vitro effects of sildenafil on non-adrenergic, non-cholinergic and nitric oxide (NO)-mediated cavernosal smooth muscle relaxation in diabetic rabbits, since alterations in this pathway are recognised in diabetic erectile dysfunction. Diabetes mellitus was induced in male New Zealand White rabbits with alloxan. Cavernosal strips from age-matched control, 3- and 6-month diabetic animals were mounted in organ baths. Relaxation responses to electrical field stimulation (1-20 Hz) or sodium nitroprusside (10(-8)-10(-4) M) were assessed in the absence and presence of sildenafil (10(-8) and 10(-7) M). The effect of sildenafil on cGMP formation by the corpus cavernosum was also assessed following stimulation with sodium nitroprusside, A23187 and acetylcholine. Sodium nitroprusside-stimulated relaxations were significantly (P<0.03) impaired in the corpus cavernosum from both diabetic groups, (IC(50)=4.6 x 10(-6) M following 3 months of diabetes mellitus and 4.0 x 10(-6) M following 6 months of diabetes mellitus; compared to 7.5 x 10(-7) M for pooled age-matched controls). Sildenafil (10(-7) M) significantly enhanced sodium nitroprusside-stimulated relaxation in control (P<0.05) and diabetic groups (P<0.03). Electrical field stimulation-mediated relaxations of the corpus cavernosum were significantly impaired after 6-month diabetes mellitus and enhanced by sildenafil (10(-8) M). cGMP formation by the diabetic corpus cavernosum was impaired significantly, but restored towards normal by sildenafil. We suggest that the impairment of NO-mediated relaxation of the corpus cavernosum reflect, at least in part, a defect in guanylyl cyclase activity. These findings support the use of sildenafil as an effective, orally administered, treatment for diabetic erectile dysfunction.

Neurologic erectile dysfunction

Neurologic erectile dysfunction presents a diagnostic and treatment challenge to the internist and urologist. Multiple chronic disease modalities and traumatic etiologies exist. Education regarding these conditions and a detailed and thorough history and office work-up are the best resources for the clinician. Treatment can follow the model of proceeding from the least to most invasive procedure (process of care), taking into account patient and partner satisfaction. Because the psychology of grief and loss may enter into treatment of some neurologic conditions (e.g., erectile dysfunction after radical retropubic prostatectomy, spinal cord injury, or chronic diseases), a whole-patient approach encompassing psychotherapy is warranted.

Acetylcholine release in human heart atrium: influence of muscarinic autoreceptors, diabetes, and age

BACKGROUND

An imbalance of sympathetic and parasympathetic drive to the heart is an important risk factor for cardiac death in patients with coronary heart disease, diabetes, and renal insufficiency. The amount of neurotransmitter released from peripheral autonomic nerves is modulated by presynaptic receptor systems. In analogy to alpha-autoreceptors on sympathetic nerves, muscarinic autoreceptors activated by endogenous acetylcholine may exist on parasympathetic nerves in the human heart.

METHODS AND RESULTS

We developed a technique to study acetylcholine release from human atria and investigated muscarinic autoreceptor function. A pharmacological and molecular approach was used to characterize the subtype involved. Of the 5 muscarinic receptor subtypes cloned, only mRNA encoding for M(2)- and M(3)-receptors were detected. Potencies of several muscarinic antagonists against the release-inhibiting effect of the nonselective muscarinic agonist carbachol at the cardiac autoreceptor were correlated with published data for human cloned M(1)- through M(5)-receptors.

CONCLUSIONS

This analysis clearly indicates that acetylcholine release in human atria is controlled by muscarinic M(2)-receptors. Blockade of these receptors by atropine doubles the amount of acetylcholine released at a stimulation frequency of 5 Hz. In atria of patients >70 years of age and patients with late diabetic complications, acetylcholine release is reduced. Locally impaired cardiac acetylcholine release may therefore represent a pathophysiological link to sudden cardiac death in elderly and diabetic patients.

The effect of superoxide dismutase on nitric oxide-mediated and electrical field-stimulated diabetic rabbit cavernosal smooth muscle relaxation

OBJECTIVE

To investigate the effect of superoxide dismutase (SOD, the enzyme that accelerates the breakdown of the superoxide anion, O2- to H2O) on nitric oxide (NO)-mediated and electrical field stimulated (EFS) relaxation in diabetic rabbit cavernosal smooth muscle. Materials and methods Diabetes was induced with alloxan (65 mg/kg) in six adult New Zealand White rabbits. After 6 months, cavernosal smooth muscle strips from age-matched controls and diabetic animals were mounted in organ baths. After precontraction with phenylephrine (10 micromol/L) in the presence of atropine (1 micromol/L), guanethidine (5 micromol/L) and indomethacin (10 micromol/L), relaxation responses to EFS (1-20 Hz), carbachol (10(-8)-10(-4) mol/L) and sodium nitroprusside (SNP, 10(-9)-10(-4) mol/L) were assessed in the presence and absence of SOD (100 IU/mL).

RESULTS

SNP- and carbachol-mediated (endothelium-independent and -dependent, respectively) relaxations were impaired in the diabetic cavernosal smooth muscle strips compared with controls (concentration required for 50% inhibition, 1.4 micromol/L for diabetic and 0.75 micromol/L for control with SNP, and 44 micromol/L for diabetic and 0.4 micromol/L for control with carbachol). SOD significantly enhanced both SNP- and carbachol-mediated diabetic cavernosal smooth muscle relaxations (both P < 0.05). EFS-mediated relaxations were also significantly (P < 0.05) impaired in the diabetic cavernosal smooth muscle strips; these relaxations were also significantly (P < 0.05) enhanced by SOD.

CONCLUSION

NO- and EFS-mediated cavernosal smooth muscle relaxation is impaired in a rabbit model of diabetes but SOD significantly reversed the impaired relaxation. Therefore, in diabetes, the generation of reactive oxygen species may play an important role in the development of erectile dysfunction.

Pharmacotherapeutic advances in the treatment of erectile dysfunction

An estimated 20 million to 30 million American men have erectile dysfunction (ED). The past 2 decades of research defining erectile physiology and investigating the pathogenesis of ED have led to the recognition of a predominantly vascular basis for organic male sexual dysfunction. These scientific advances have laid the foundation for the advent of pharmacotherapies. The Food and Drug Administration approval of intracavernosal, intraurethral, and oral pharmacotherapeutics for ED has revolutionized non-surgical management of this condition. The primary care physician is faced with the challenges of diagnosis and treatment of ED, as well as referral of patients to urologists. In this article, erectile physiology and pathophysiology are reviewed, and pharmacotherapeutics are classified and discussed by their mechanisms of action and the means of administration. A thorough understanding of these new therapeutic options is key to the accurate diagnosis and successful treatment of ED and maximal patient satisfaction and care.

Autonomic nerve involvement and venous leakage in diabetic men with impotence

OBJECTIVE

To determine the neurophysiological and vascular factors in diabetic impotence, particularly the role of autonomic neuropathy on venous leakage and erectile impotence.

PATIENTS AND METHODS

Thirty-four diabetic men with impotence were investigated using various neurophysiological and radiological methods. The results were compared with those from patients with idiopathic penile venous leakage for autonomic neuropathy, especially for spontaneous cavernosal activity (SCA).

RESULTS

Of the neurophysiological tests, the SCA was most frequently abnormal, with the loss of normal periodic oscillations. Penile venous leakage, either alone or with arterial insufficiency, was the most frequent vascular problem (67%) in patients with diabetic impotence, in whom the SCA was absent in most (83%). Conversely, the SCA was normal in all impotent patients with idiopathic venous leakage.

CONCLUSION

Venous leakage in diabetic patients is probably produced by autonomic dysfunction of the penile vascular innervation or degeneration of penile smooth muscles, because the SCA was absent more often in these patients.

Evaluation of the role of corpus cavernosum electromyography as a noninvasive diagnostic tool in male erectile dysfunction

Corpus cavernosum electromyography (EMG) and its evolution: single potential analysis of cavernous electrical activity (SPACE) seem to be promising diagnostic methods in the evaluation of erectile dysfunction and smooth muscle integrity. Our study concentrates on the role of EMG in the evaluation of corpus cavernosum smooth muscles, using it as a noninvasive technique for demonstrating autonomic erectile dysfunction through their influence on recording SPACE and consequent proper selection of patients for different therapeutic modalities. A total of 80 male patients were examined for the feasibility of transcutaneous registration of cavernous electrical activity with a 2-channel electrophysiological unit (Evamatic 2000, Dantec) with two surface electrodes bilaterally placed on the penile shaft. Ten patients had normal erectile function, but complained of other urological symptoms. They served as the controls for normal electrical activity. Fifty patients with organic impotence of nonvascular (neurogenic) or vascular (venogenic, arteriogenic) aetiologies were subjected to EMG in both the flaccid and the erect state. On the basis of the EMG patterns the patients were divided into the following groups: 34 patients having normal tracing in both the flaccid and the erect state, and 21 patients showing abnormal patterns of waves with evidence of autonomic neurogenic dysfunction and incomplete smooth muscle relaxation. Of the latter 4 had long-standing diabetes mellitus and 4 had spinal injuries.

Diabetic sexual dysfunction

Although the overall incidence of erectile dysfunction in the general population between the ages of 40 and 70 years is 52%, men with diabetes mellitus have impotence at an earlier age and with a significantly higher prevalence, ranging as high as 75%. Numerous advances have been made in understanding the physiologic and biochemical mechanisms controlling penile erection. Improved clinical techniques for the diagnosis and treatment of impotence, including dynamic vascular testing, intracavernosal pharmacotherapy, and microsurgical revascularization, have allowed us to enter a new and exciting era in the quest for a more complete understanding of erectile dysfunction.

New insights into the local regulation of blood flow by perivascular nerves and endothelium

Blood flow, particularly in the skin, is essential for the success of plastic surgical operations. This review describes recent studies of the perivascular nerves and vascular endothelial cells which regulate blood flow. Perivascular nerves, once considered simply adrenergic or cholinergic, release many types of neurotransmitters, including peptides, purines and nitric oxide. Cotransmission (synthesis, storage and release of more than one transmitter by a single nerve) commonly takes place. Some afferent nerves have an efferent (motor) function and axon reflex control of vascular tone by these "sensory-motor" nerves is more widespread than once thought. Endothelial cells mediate both vasodilatation and vasoconstriction. The endothelial cells can store and release vasoactive substances such as acetylcholine (vasodilator) and endothelin (vasoconstrictor). The origins and functions of such vasoactive substances are discussed. Endothelial vasoactive substances may be of greater significance in the response of blood vessels to local changes while perivascular nerves may be concerned with integration of blood flow in the whole organism. The dual regulation of vascular tone by perivascular nerves and endothelial cells is altered by aging and conditions such as hypertension, as well as by trauma and surgery. Studies of vascular tone in disease and after denervation or mechanical injury suggest possible trophic interactions between perivascular nerves and endothelial cells. Such trophic interactions may be important for growth and development of the two control systems, particularly in the microvasculature where neural-endothelial separation is small.

Pathophysiology of erectile dysfunction

During the past decade, our knowledge of the hemodynamics, functional anatomy, neurophysiology, and neuropharmacology of erectile function has evolved substantially. The change of smooth muscle tone has emerged as a key factor in erection and detumescence. However, future studies are needed to elucidate the cellular and molecular basis of erectile physiology. With insight into normal physiology we will understand the pathologic process and be able to treat it.

Evaluation of erectile dysfunction by dynamic infusion cavernosometry and cavernosography (DICC). Multi-institutional study

In a cooperative, private practice, multi-institutional impotence study, dynamic infusion cavernosometry and cavernosography (DICC) was performed on 743 patients to make an accurate diagnosis and/or identify candidates for penile revascularization. Maximum equilibrium intracorporeal pressure achieved following papaverine and phentolamine injection (Phase I) averaged 29.42 +/- 0.76 mm Hg, approximately one third of normal erection pressure. Corporeal pressure fall from 150 mm Hg over thirty seconds (cavernosometry) averaged 82.38 +/- 1.33 mm Hg (Phase II). The gradient between systolic and cavernosal artery pressure averaged 42.84 +/- 1.12 mm Hg on the right and 43.33 +/- 1.13 mm Hg on the left (Phase III). Cavernosography at 90 mm Hg erection pressure was performed in Phase IV. Of the 124 patients from one center who were reviewed in greater detail, pure cavernosal artery insufficiency (CAI) was found in 25 (20.2%), corporeal veno-occlusive dysfunction (CVOD) in 26 (21.0%), and 73 patients (58.9%) demonstrated combined CAI and CVOD. Diabetics (n = 69) achieved lower equilibrium intracorporeal pressures than nondiabetics, had similar CVOD, and worse CAI. Smokers (n = 365) and patients with Peyronie's disease (n = 32) had erectile dysfunction similar to those without these conditions. Patients impotent after trauma (n = 124) were younger, achieved higher intracorporeal pressures, and showed better corporeal veno-occlusive function than those without trauma. Complications of DICC were minimal and infrequent. After DICC, 169 patients underwent internal pudendal arteriography, 105 had arterial bypass surgery with or without penile venous ligation procedures, and 45 had venous surgery alone. Dynamic infusion cavernosometry and cavernosography is a useful erectile function study to evaluate impotence and can be performed easily in a private practice setting.