The hypoactive corpora cavernosa with degenerative erectile dysfunction: a new syndrome

Background

In a group of 22 patients with erectile dysfunction, vasculogenic, neurogenic, endocrinologic or psychogenic investigations failed to find a cause for their erectile dysfunction. The electro-cavernosograms of these patients recorded a diminished activity. We investigated the hypothesis that diminished corpus cavernosum electromyography activity was the cause of erectile dysfunction in these patients.

Methods

The study comprised the above mentioned 22 patients (study group, 43.8 ± 5.9 SD years) and 15 healthy volunteers (control group, 41.8 ± 5.1 SD years). The electro-cavernosograms were recorded in the flaccid, erectile and detumescent phases by 2 electrodes inserted into the corpus cavernosum.

Results

The electro-cavernosogram of the healthy volunteers registered in the flaccid phase regular slow waves and random action potentials. The wave variables declined significantly in the erectile phase (p < 0.01). In the study group, the slow wave variables in the flaccid phase exhibited a significant decrease (p < 0.05) compared to the healthy volunteers, and the rhythm was irregular. Erection did not occur with sildenafil administration or intracavernosal papaverine injection, and penile implant was performed. Biopsy examination showed degenerated muscle fibers, and fragmented collagen and elastic fibers with areas of fibrosis.

Conclusion

A novel concept of the cause of erectile dysfunction was presented. Corpora cavernosa showed degenerative changes on histopathologic examination and exhibited diminished electromyography activity. They did not respond to sildenafil administration or intracavernosal papaverine injection. Penile implants were the only treatment. The condition is given the name 'hypoactive corpus cavernosum'. The cause of corpus cavernosum degenerative changes needs further study.     

Effects of transanal pelvic plexus stimulation on penile erection: clinical implications

Objective To determine the ability of transanal pelvic plexus stimulation (TPPS) in inducing penile tumescence in patients with non-neurogenic erectile dysfunction (ED) and to compare the erection degree with papaverine-induced erection. Patients and methods The cavernous electrical activity (CEA) in 21 men with non-neurogenic erectile dysfunction was measured during TPPS by electromyography of corpus cavernosum and the erection degree of penis (flaccid, semi-rigid, rigid) was noted. The stimulation amplitude was increased from 20 to 100 mA. All patients also underwent intracavernous papaverine injection and further CEA recordings were obtained. Results Twelve and nine patients were diagnosed with vasculogenic (VED) and non-vasculogenic ED (NVED), respectively. TPSS led to a penile erectile response in 12 patients (57%), whereas papaverine injection caused erection in 16 (76.2%) patients. The mean baseline CEA (16.9 ± 9.1 mV) did not change with TPPS, but papaverine significantly decreased the mean CEA to 12.3 ± 4.9 mV (P < 0.001). CEA recordings of 16 (76.2%) patients revealed a significant decrease after papaverine injection, however seven (33.3%) patients showed significant CEA decrease in response to TPPS. Both TPPS and papaverine were observed to have a higher effect in patients with NVED in terms of inducing penile erection and decreasing CEA compared to their effects in patients with VED. Conclusion TPPS induces penile erection and decreases CEA for some extent, but to a lesser degree compared to papaverine. As further improvements are achieved in the methodology of TPPS, it may be a valuable method in the evaluation patients with erectile dysfunction.     

Standardized evaluation of erectile dysfunction in 95 consecutive patients

We investigated 95 patients referred for erectile dysfunction by penile blood pressure measurement, the intracavernous papaverine test and Doppler investigation of the penile arteries. Furthermore, penile cutaneous perception threshold, bulbocavernosus reflex latency and somatosensory cortical evoked potentials of the pudendal nerve were measured. In selected cases cavernosometry, cavernosography and corpus cavernosum electromyography were performed. Doppler investigation of the cavernous arteries after papaverine injection was more reliable than penile blood pressure measurement in the diagnosis of arteriogenic erectile dysfunction. Decreased sensibility of the penis may be the sole factor responsible for inability to sustain an erection. Erectile dysfunction may be provoked by impaired function of the pudendal nerve. Penile cutaneous perception threshold measurement and corpus cavernosum electromyography are mandatory in the evaluation of neurogenic etiology. Cavernosometry and cavernosography are reliable methods in the determination of abnormal drainage from the corpus cavernosum.     

Corpus cavernosum electromyography: could it be a parameter to predict ageing?

In this study, we investigated whether electromyography of corpus cavernosum (CC-EMG) results vary with age and whether CC-EMG could be a parameter to predict ageing of cavernous smooth muscle. Recordings of electrical activity of corpus cavernosum (EACC) were retrospectively investigated in 134 patients with erectile dysfunction. Penile colour Doppler ultrasonography and cavernosometry were also performed for all of the patients. The total number and duration of EACC and amplitudes between positive and negative peaks were compared between the flask state for 10 min and after intracavernosal papaverine injection. The mean age of the 47 patients in group 1 was 35.2 ± 6.3 years (range, 23-44), the mean age of the 45 patients in group 2 was 51.1 ± 3.1 years (range, 45-56) and the mean age of the 42 patients in group 3 was 61.8 ± 4.6 years (range, 57-77). Total IIEF-5 score was 7.6 ± 2.1 in group 1, 7.9 ± 2.4 in group 2 and 7.9 ± 2.1 in group 3. There were no statistically significant differences among the groups regarding electrical potential frequencies, durations and amplitudes of electromyographic recordings. Conclusion: We do not think that CC-EMG findings could be used efficiently as a predictor of ageing.     

The value of corpus cavernosum electromyography in erectile dysfunction: current status and future prospect

In the last decade, several investigators have tried to develop corpus cavernosum electromyography (CC-EMG) as a direct clinical method to evaluate the state of the penile autonomic innervation and the cavernous smooth muscle. Both basic and clinical studies have shown promising results. However, its application as a diagnostic tool with clinical relevance was hindered by insufficient knowledge of cavernous smooth muscle electrophysiology, lack of standardization, technical and practical difficulties and problems in the interpretation of the results. Recently, the European Commission created the so-called COST Action B18 (corpus cavernosum EMG in erectile dysfunction), aiming to strengthen the coordination of the European research groups and give the development of CC-EMG a new impetus. This review presents an overview of the physiological background, the current status of CC-EMG, and discusses possibilities for further developments.     

Evoked cavernous activity.

PURPOSE: Corpus cavernosum electromyography has been widely done to evaluate autonomic dysfunction in patients with erectile dysfunction. We assessed the value of corpus cavernosum electromyography, evoked cavernous activity and penile sympathetic skin responses for their accuracy in determining autonomic involvement in cases of erectile dysfunction. MATERIALS AND METHOD: We evaluated 75 men with erectile dysfunction by corpus cavernosum electromyography, evoked cavernous activity and penile sympathetic skin response tests at our neurourology laboratory. The etiology of dysfunction was vascular, neurogenic, psychogenic or mixed based on a detailed medical and sexual history, physical examination, electrophysiological and laboratory studies, penile color Doppler ultrasonography, and cavernosography and/or cavernosometry. Autonomic involvement was clinically assessed by systemic findings, such as orthostatic hypotension, impaired gastrointestinal motility, sinus dysrhythmia and secretomotor changes. A concentric electromyography needle placed in the right cavernous body was used to record corpus cavernosum electromyography and evoked cavernous activity. The right median nerve was stimulated electrically with 13 to 16 mA. to determine evoked cavernous activity and the penile sympathetic skin response. The latter response was recorded with silver disc electrodes placed on the left cavernous body. All tests were performed using an electromyography/evoked potential machine. We determined the relationships among corpus cavernosum electromyography, evoked cavernous activity and penile sympathetic skin response tests in respect to etiological factors. RESULTS: The 56 patients with normal corpus cavernosum electromyography activity had also evoked cavernous activity and a penile sympathetic skin response except for 1 with no penile sympathetic skin response but evoked cavernous activity. None of these patients had autonomic neuropathy. Of the 19 patients without corpus cavernosum electromyography activity 11 had evoked cavernous activity, including 10 with no autonomic neuropathy. The remaining 8 patients had no evoked cavernous activity, of whom 7 had autonomic neuropathy. A penile sympathetic skin response was recorded in 18 men with absent corpus cavernosum electromyography. CONCLUSIONS: Due to false-negative results on corpus cavernosum electromyography and penile sympathetic skin response testing evoked cavernous activity seems more reliable for determining autonomic involvement in the pathophysiology of erectile dysfunction.     

电刺激阴茎背神经和海绵体内注射药物诱导大鼠阴茎海绵体内压反应

目的:评价阴茎海绵体内压(ICP)监测在电刺激阴茎背神经和海绵体内注射罂粟碱诱导大鼠阴茎勃起反应中的应用。方法:选取性成熟雄性SD大鼠8只,20%氨基甲酸己酯(1000mg/kg)腹腔注射麻醉下,暴露阴茎并解剖阴茎背神经(DN),将充满肝素盐水并连接于压力传感器的25G针头插入一侧海绵体,取另一30G头皮针插入对侧海绵体,分别用于测定ICP和注射血管活性药物。分别以电刺激海绵体神经(刺激参数:电压4V,波幅0.5ms,频率16Hz,持续20s)和海绵体内注射罂粟碱(0.4mg)诱发阴茎勃起,采用SMUPPC型生物信号处理系统记录ICP变化。结果:麻醉大鼠的ICP基线水平为(12.3±3.1)mmHg(1mmHg=0.133kPa),DN电刺激后约30～60sICP明显升高[(36.4±2.3)mmHg,P<0.05],电刺激结束后缓慢下降至基线水平。海绵体内注射罂粟碱后5～8min可诱发ICP明显升高[(28.4±6.1)mmHg,P<0.05]。结论:监测电刺激大鼠DN及海绵体内药物注射诱发的ICP,为阴茎勃起这一复杂神经血管活动的动物模型在体实验研究提供了一种客观准确的科学工具,对于进一步研究阴茎勃起生理和勃起功能障碍的发病机制,评价治疗勃起功能障碍新疗法的疗效等具有重要意义。     

Corpus cavernosum electromyography (CC-EMG): A new technique in the diagnostic work-up of impotence

We have studied cavernous electrical activity in 42 subjects, healthy volunteer controls and groups of impotent, patients using a nonspecific electromyographic device (PICO-MENFIS) and a specific one, the SPACE-recorder 7500 designed to achieve electric recordings from the corpora cavernosa. In all of the patients, we detected under basal conditions a mean amplitude of 583±323 μV, a mean duration of 4.9±7 s,a mean polyphasicity of 3.5±1.4. It should be emphasized that a significant reduction of potential amplitudes was recorded after pharmacological stimulation in both the controls and the impotent patients. The healthy controls showed amplitudes significantly higher than the impotent patients after radical cystectomy (715±141 μV versus 381±227 μV, p<0.01). The patients after a “nerve-sparing” radical cystectomy with a mean amplitude similar to the controls (500–700 μV) reacted well to the intracavernous drugs in a high percentage of cases. In our experience, CC-EMG seems to be a reliable method which can pinpoint directly lesions to the cavernous smooth muscle and penile autonomic nerves. It has also been able to assess the effects of stress, anxiety and pain on the erectile mechanisms.     

Relaxation degree: A new concept in erectile dysfunction

Purpose: To investigate the clinical application of the new parameter'Relaxation Degree.Patients and methods: Chart reviews of 150 patients were evaluatedretrospectively of whom 96 had been diagnosed as pure cavernoocclusivedysfunction (COD) by using corpus cavernosum electromyography (CC-EMG) and cavernosometry and of whom 54 had been diagnosed as psychogenic erectile dysfunction by normal CC-EMG; cavernosometry and pulsedoppler scanning. Relaxation degree was defined as the percent decreasein the amplitudes of the electrical activity of corpus cavernosum (EACC).Results: Mean relaxation degree measurements were found as 66.5%,66.28% and 16% in minimal, moderate and severe COD groups respectively.This value was 80% in psychogenic erectile dysfunction group. Statisticalcomparisons were found significant between minimal and severe andmoderate and severe COD groups. All three organic erectile dysfunctiongroups were also compared with psychogenic erectile dysfunction groupwhere differences were found significant. If the normal relaxation degreewas accepted as more than 80%, COD could be diagnosed with 93% specifityand 98% sensitivity without performing cavernosometry.Conclusion: Relaxation degree parameter could be used in diagnosisof COD showing the percent relaxation ability of the cavernous smoothmuscle as a non invasive method when compared with cavernosometry.     

Venous surgery in erectile dysfunction: a critical report on 116 patients

From June, 1985, to December, 1987, we operated on 116 impotent patients suffering from venous incompetence of the cavernous bodies. A total of 115 patients underwent ligation of the deep dorsal vein of the penis. After a mean follow-up of 12.9 months, 67 patients (58.3%) were still able to obtain satisfactory erections. In 39 cases (33.9%), however, adjuvant corpus cavernosum autoinjection therapy was necessary. Eleven patients were submitted to spongiosolysis after ligation of the deep dorsal penile vein because of a distal venous leakage, consisting of venous shunts between the corpora cavernosa and the corpus spongiosum. After a mean follow-up of 14.2 months, 9 patients (81.8%) reported excellent penile rigidity; 5 of these patients, however, needed corpus cavernosum autoinjection therapy to maintain erectile function. One patient with ectopic veins emerging from the right crus of the penis was operated on successfully from a perineal approach. Serious complications did not occur in any of the patients. Despite the recurrence rate of 13 percent, venous surgery is an effective treatment for most patients concerned and offers a more physiologic erectile function than can be achieved by implantation of a penile prosthesis.     

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 [4]. 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.     

Evaluation of a no-needle penile injector: a preliminary study evaluating tissue penetration and its hemodynamic consequences in the rat

Objectives

Intracavernous needle injection is an effective delivery method for pharmacotherapy of erectile dysfunction. Needle phobia, pain, and concern about local tissue injury have stimulated the search for new, less invasive means of inducing penile erection. In this preliminary communication, we evaluate a jet injector as an alternative to needle injection for intracavernous delivery of vasoactive drugs.

Methods

Jet injection was evaluated in three groups of rats receiving either India ink, saline, or papaverine into the penis. The ability of the jet injection to penetrate through the tunica albuginea and deliver liquid to the corpora cavernosa smooth muscle was assessed by the degree of staining within the corpus cavernosum (ink group), histologic change (saline group), and rise in intracavernous pressure (papaverine group). Erectile capacity following cavernous nerve electric stimulation was compared before and 1 hour after injection of saline or papaverine.

Results

Ink traversed the skin and tunica albuginea with extensive deposition noted within the cavernous spaces. Varying degrees of subcutaneous hemorrhage were seen with saline jet injection; however, the corpus cavernous smooth muscles showed no evidence of injury. Jet injection of papaverine 3250 gmg significantly increased cavernous pressure (39.4 ± 4.6 cm H₂O) compared with saline injection (2.8 ± 1.3 cm H₂O).

Conclusions

We conclude that acute jet injection is an effective method for intracavernous delivery of drugs. Long-term effects should be evaluated prior to clinical use.     

Multifactorial evaluation of diabetic erectile dysfunction

We determined arterial venous and sinusoidal factors in 20 patients with insulin dependent diabetes mellitus and erectile dysfunction by performing dynamic infusion cavernosometry (DIC), colour flow Doppler ultrasonography, penile biothesiometry and corpus cavernosum electromyography (CCE). DIC, colour flow Doppler ultrasonography and penile biothesiometry were done in standard fashion except for CCE. Paradoxical increase in the electrical activity of corpus cavernosum after intracavernous (IC) papaverine was called a discoordination that was due to cavernous smooth muscle contraction instead of relaxatoon. Arterial and accompanying pathologies were found in 10 (50%) patients. In 3 (15%) of them pure arterial pathology, in 6 (30%) patients arterial and veno-occlusive dysfunction (VOD) and in one patient arterial pathology with abnormal biothesiometry were found. VOD and accompanying pathologies were found in 12 (60%) patients. In 6 (30%) of them VOD and arterial, in 4 (20%) patients VOD and discoordination and in 2 (10%) patients VOD and abnormal biothesiometric values were present. A higher frequency and coexistence of VOD and discoordination pattern were observed. In conclusion, patients with diabetic impotence show a wide range pathophysiology of erection and the evaluation of these patients must include multistep techniques.     

The intracavernous injection of papaverine as a diagnostic procedure in patients with erectile dysfunction

To evaluate the use of papaverine-induced erection as a diagnostic test in men with erectile dysfunction, 24 patients had papaverine injected into the corpus cavernosum. The results of the papaverine test in combination with the tentative diagnosis, based upon patient history, clinical examination and peno-brachial pressure index, gave in most cases sufficient information about the function of the penile vessels to decide in which patients a selective arteriography or a cavernosography was indicated. Two patients developed priapism after the papaverine injection.     

Electrical activity of the corpus cavernosum in denervated rats

BACKGROUND: We evaluated the electrical activity of the corpus cavernosum after intracavernous papaverine injection in rats that had been denervated experimentally. METHODS: Twenty-four male adult Sprague Dawley rats were divided into three groups: (i) controls (n=8) (ii) unilateral cavernous nerve resection on the right side (n=8); and (iii) bilateral cavernous nerve resection (n=8). Through a suprapubic incision, the urinary bladder was retracted laterally to locate the major pelvic plexus on the lateral surface of the prostate. The major branch of the cavernous nerve, running caudally from the pelvic plexus, was isolated and excised using an operating microscope. Three weeks later, recording of the electrical activity of the corpus cavernosum (EACC) was performed by using a Neuropack-2 EMG unit (Nihon Kohden, Tokyo, Japan) and coencentric needle electrode. Changes in amplitude were evaluated before and after intracavernosal papaverine injection. The results in the flaccid state and after papaverine injection were compared by using the Mann Whitney U-test in all three groups and paired t-test between groups. RESULTS: In the flaccid penis, the mean (+/- SD) amplitude of electrical activity of the corpus cavernosum was 17.42+/-2.05, 12.42+/-1.88, 9.71+/-1.59 and 5.85+/-0.96 microV in control rats, in unilaterally denervated rats (in which the cavernous nerve was intact on the left side), in unilaterally denervated rats in which the cavernous nerve was resected on the right side and in bilaterally denervated rats, respectively. In the flaccid state, EACC is lower in the bilaterally denervated group than in the control and unilaterally nerve-resected groups (P < or = 0.05). The recording of electrical activity of the corpus cavernosum was continued for 20 min after papaverine injection. In the control group and in both groups of unilaterally denervated rats, we observed a significant decrease in the electrical activity of the corpus cavernosum in the first 5 min after papaverine injection (P < or = 0.05). However, no difference was observed in bilaterally denervated rats after injection (P > or = 0.05). CONCLUSIONS: We conclude that electrical activity of the corpus cavernosum continues after unilateral nerve injury in rats. Cross-innervation may play a role in penile innervation and corpus cavernosum electromyography shows electrical activity in denervated rats.     

Penile extensibility and erectile function. Preliminary results

Extensibility, one of the main biomechanical functions of the penis, has been studied in 422 subjects. Preliminary results showed that a) the flaccid penis was extensible; b) this extensibility was significantly correlated with both age and erectile function. Thus, the more penile extensibility decreased, the more erectile function became impaired. This loss of extensibility is caused by fibrosis of the penis, that mainly affects the corpus cavernosa and, by reducing distensibility, impairs the vascular events involved in erection. Evaluation of the extensibility of the flaccid penis is a new, simple, no-invasive and reproducible clinical test. It contributes to the etiologic diagnosis of impotence by detecting tissular anomalies of the erectile corpora.     

Intracavernosal pressure monitoring in mice: responses to electrical stimulation of the cavernous nerve and to intracavernosal drug administration

With the development of transgenic mice to evaluate mechanisms of erectile function, it appears particularly advantageous to develop a standardized mouse model of penile erection. The purpose of the study reported here was to evaluate the novel application of intracavernosal pressure (ICP) monitoring in the mouse during electrophysiologic and pharmacologic induction of penile erection. In anesthetized adult male mice, the cavernous nerves (CN) were isolated unilaterally, and the corpora cavernosa were exposed. A 24-gauge angiocath (intravenous catheter) was inserted into the right corpus cavernosum to monitor the ICP, and a 30.5-gauge needle was inserted into the left corpus cavernosum for intracavernosal drug administration. ICP was recorded during CN-stimulated or pharmacostimulated erections. Electrical stimulation of the CN significantly increased the ICP (from 10.09 +/- 2.01 to 34.62 +/- 2.71 mm Hg, P < .05), which then returned to baseline pressure after termination of the electrical stimulation. Pretreatment with intracavernosal administration of the nitric oxide synthase inhibitor, nitro-L-arginine methyl ester (0.1 mg), inhibited the electrical stimulation-induced changes in ICP (7.17 +/- 1.46 vs 10.38 +/- 2.17 mm Hg, not significant [NS]). Also, intracavernosal administration of papaverine (0.4 mg) produced a significant increase in ICP (from 8.51 +/- 0.69 to 26.37 +/- 5.7 mm Hg, P < .05). We concluded that this technique might be applied to perform quantitative erection physiologic experiments with the mouse as an economical and experimentally advantageous animal model, particularly with the development of transgenic mice to evaluate mechanisms of erectile function.     

Another surgical approach for vasculogenic impotence

Until recently, a defect in the capability of blood to be trapped in the corpus cavernosum so that adequate penile turgidity can be maintained for successful intercourse has not been considered a major etiology for impotence. A diagnostic test called dynamic cavernosography was developed that consists of a cine-taped cavernosogram in conjunction with intracavernous pressure measurements at 3 different cavernous infusion rates. The results of 104 of these tests are presented. More recently, 17 of these patients also have undergone papaverine tests. Of the patients 59 per cent had no or only partial erections at all infusion rates and pressure did not increase to greater than 50 mm. Hg. The papaverine test showed only partial or no tumescence when 60 mg. were injected into the corpora. As a result, 25 patients underwent a penile operation to remove some venous outflow channels. Of the patients who underwent an operation for absent tumescence at any flow rate and who had a large number of venous channels draining the corpora cavernosa on the cavernosogram 59 per cent were potent postoperatively.     

可分泌表达人降钙素基因相关肽重组腺相关病毒对糖尿病大鼠阴茎勃起的作用

目的:探讨重组腺相关病毒(rAAV)介导人降钙素基因相关肽(hCGRP)基因转移在糖尿病大鼠阴茎海绵体平滑肌分泌表达及其对阴茎勃起的作用。方法:建立链佐脲菌素(STZ)糖尿病大鼠模型,随机分为3组,分别将VssHGCMV-hCGRP、VssCMV-GFP和rAAV空病毒液注射于阴茎海绵体。在注射后5 d,采用SMUP-PC型生物信号处理系统检测阴茎背神经电刺激诱发的阴茎勃起反应及海绵体内压(ICP)变化。切取海绵体组织,通过免疫组化技术和激光共聚焦显微镜分别检测hCGRP和绿色荧光蛋白(GFP)表达,以放射免疫法检测组织中环磷酸腺苷(cAMP)和环磷酸鸟苷(cGMP)变化。结果:在VssCMV-GFP转染后5 d,显示阴茎海绵体内几乎所有组织均有广泛的GFP表达,而rAAV空病毒转染的海绵体则无GFP表达。VssHGCMV-hCGRP转染STZ诱导的糖尿病大鼠后5d,电刺激阴茎背神经可诱发明显的阴茎勃起,监测ICP明显增高[(60.5±4.5)mm Hg,1 mm Hg=0.133kPa],而对rAAV空病毒转染的对照组STZ糖尿病大鼠以同样的参数电刺激阴茎背神经则无勃起反应,ICP无明显增加[(22.3±1.3)mm Hg],两组差异有显著性(P<0.01)。免疫组化观察显示在VssHGCMV-hCGRP转染的STZ糖尿病大鼠阴茎海绵体组织中hCGRP表达增强,同时当电刺激阴茎背神经诱发勃起反应时,海绵体内cAMP和cGMP水平均升高,分别为(48.4±6.5)nmol/L和(21.2±13.6)nmol/L,较rAAV空病毒组[(16.7±2.5)nmol/L和(0.42±0.12)nmol/L]明显增高(P<0.01)。结论:经阴茎海绵体内注射重组腺相关病毒VssHGCMV-hCGRP在糖尿病大鼠阴茎海绵体内获得了hCGRP转基因高效表达,其可增加阴茎背神经电刺激诱发的阴茎ICP和勃起反应。     

Pathophysiology of Erectile Dysfunction

Physiology of erection and pathophysiology erectile dysfunction is reviewed. Analysis is obtained from basic and clinical research including animals studies, anatomical studies, and molecular and cellular research on corporal tissue obtained during penile prosthesis implantation. Supraspinal influences and spinal influence on penile erection has been learned from spinal cord injury patient. Corporal smooth muscle relaxation of penile arteries and corpus cavernosum leads to penile erection, results from parasympathetic/nonadrenergic noncholinergic neural pathway activation and simultaneous inhibition of sympathetic outflow. Anatomical studies taught understanding of the mechanism for restriction of blood outflow from the corpora cavernosa. The change of smooth muscle tone has emerged as a key factor in erection and detumescence. Many independent factors converge on the modulation of corporal smooth muscle tone. Neuronal and local neurotransmitter effects via gap junction, potassium channels, and calcium channel. A nitric oxide/cyclic guanosine monophosphate mechanism as well as cyclic aminomonophosphate has an important role in mediating the corporal smooth muscle relaxation necessary for erectile function. Erectile dysfunction can be due to vasculogenic, neurogenic, hormonal, veno-occlusive, psychogenic and/or pharmacogenic factors as well as alterations in the nitric oxide/cyclic guanosine monophosphate (cGMP) or cyclic aminophosphate (cAMP) pathway or other regulatory mechanisms including gap junction or ionic channel resulting in an imbalance in corporal smooth muscle contraction and relaxation. Our present knowledge of the hemodynamics, functional anatomy, neurophysiology, and neuropharmacology of penile erection and dysfunction at the cellular and molecular level has led to better understanding of physiology and pathophysiology of erectile dysfunction.