Butea superba (Roxb.) improves penile erection in diabetic rats

The objective of the present study was to investigate the effect of ethanolic extract of Butea superba (Roxb.) on erectile dysfunction in diabetic rats by the measurement of intracavernous pressure (ICP) and on cavernosal smooth muscle relaxation. Male Sprague-Dawley rats were induced to become diabetic by a single intravenous injection of Streptozotocin (55 mg kg(-1) body weight). The ethanolic extract at the concentration of 1, 10 and 100 mg kg(-1) BW was administered orally once a day to diabetic rats in each group for 4 weeks. Diabetic rats showed a significant decrease in both ICP and the relaxation of the cavernosal smooth muscle compared with the normal rats. The extract of B. superba significantly increased the ICP with the effective dose of 10 mg kg(-1) BW (61.00 ± 11.11 mmHg versus 39.61 ± 11.01 mmHg in the diabetic control group). Moreover, the B. superba-treated group also showed enhanced relaxation of the cavernosal smooth muscle with EC(50) of 1.17 mg ml(-1). These results suggest that the extract of B. superba enhanced penile erection in diabetic rats by increasing the ICP. This might be explained by the increased blood flow as a result of the relaxation of the cavernous smooth muscle.     

Potentiation of apomorphine effect on sildenafil-induced penile erection in conscious rabbits

Aim: To investigate a possible potentiation effect of apomorphine (APO) on sildenafil-induced penile erection in the conscious rabbit. Methods: Erection of male New Zealand White rabbits (3.5 - 4.0 kg, n=12) was assessed by measuring the length of the uncovered penile mucosa and the duration of erection before and after intravenous administration of agents. After injection of APO (0, 0.05, 0.1 and 0.4 mg/kg), sildenafil was administered intravenously in a dose-response manner (0.5, 1 and 5 mg/kg). In additional experiments, the effect of increasing doses of sildenafil in combination with APO on systemic blood pressure was evaluated. Results: Systemic administration of sildenafil induced a dose-dependent increase in the penile length. Intravenous injection of APO alone did not produce any change in the penile length, while significantly enhanced the penile erection induced by sildenafil. The co-administration of 0.1 mg/kg of APO and 1 mg/kg of sildenafil was found to be the most effective combination in producing penile erection. Intravenous administration of sildenafil caused a concentration-dependent decrease in systemic blood pressure, but no additional decrease was observed with co-administration of APO. Conclusion: APO enhances the penile erection induced by sildenafil in the conscious rabbit without causing an additional decrease in blood pressure. (Asian J Androl 2004 Sep; 6: 205-209)     

Effect of intraurethral papaverine on penile erection in rats

OBJECTIVES: The aim of this study is to investigate erectile response to intraurethral administration of papaverine in rats. MATERIAL AND METHODS: Male Sprague-Dawley rats were used in this study. Under urethane anesthesia, penis was exposed and intracavernous pressure (ICP) was recorded through a 23-gauge needle, which was inserted into right corpus cavernosum. Effects of intraurethral application of incremental doses of 0.2 ml papaverine gel (4-17.5 mg) on intracavernosal pressure were observed and compared with those of 0.4 mg papaverine applied into corpus cavernosum. Mean arterial blood pressure (MABP) and heart rate were also monitored. RESULTS: The mean basal ICP was 8.9 +/- 1.8 mm Hg. Intraurethral administration of papaverine did not increase ICP at any doses used in this study. After intracavernous injection of papaverine (0.4 mg), a significant increase in the ICP occurred from resting (8.9 +/- 1.8 mm Hg) to a peak at 57.5 +/- 9.9 mm Hg and persisted for 22.3 +/- 6.7 minutes (p < 0.05). The latter application significantly decreased MABP (22.3 +/- 3.1 mm Hg; p < 0.05). CONCLUSIONS: Intraurethral administration of papaverine does not seem to be an alternative to other erectile dysfunction treatment modalities. However, further studies on animals are necessary at higher concentrations or in combination with other mucosal enhancers to increase the effect of intraurethral administration of papaverine.     

Artificial erection by perfusion of penile arteries

The dorsal and cavernous arteries of the penis in 14 cadavers and 4 surgical specimens were studied, and the role of these vessels in producing erection was evaluated. For the first time, erection was produced in a cadaver by the perfusion of the cavernous artery. Perfusing the dorsal artery resulted in distention but not erection, and the dorsal artery showed extensive anastomoses between all six arteries of the penis. The cavernous artery appears to be very important for erection, with the dorsal artery playing a relatively smaller role. Surgically, however, both vessels may lend themselves to vascular shunts in the treatment of vasculogenic impotence.     

Topical application of a Rho-kinase inhibitor in rats causes penile erection

Studies from this laboratory have demonstrated that RhoA/Rho-kinase signaling mediates vasoconstriction in the penile circulation of the rat and that erection results from inhibition of this activity with Y-27632. In prior animal studies, Y-27632 was administered to the rats by intracavernous injection. To determine if topical application of the Rho-kinase inhibitor is an effective mode of delivery, Y-27632 was applied to the surface of the tunica albuginea or to the glans penis and surrounding skin in intact or castrated rats. Both sites of drug administration resulted in a marked increase in the erectile response both with and without stimulation of the autonomic innervation of the penile vasculature. Although high doses of the drug were found to reduce systemic blood pressure, topical administration of the Rho-kinase inhibitor, in appropriate doses, may have clinical value for the treatment erectile dysfunction.     

Functional evaluation of penile veins by cavernosography in papaverine-induced erection

Of 49 patients in whom cavernosography was performed after papaverine-induced erection 38 had abnormal venous leakage to various drainage systems (corpus spongiosum, cavernous vein or superficial and deep dorsal veins). Because the effect of papaverine on penile arteries, sinusoids and veins is similar to that caused by electrostimulation, we believe that this technique is better than other reported means of evaluating the functional status of the penile veins. However, we recommend that only patients with a normal arterial response but poor erection after papaverine injection be considered candidates for erection cavernosography, since they most likely will benefit.     

Blood gas analysis in drug-induced penile erection

To elucidate the hemodynamic changes during erection, we measured corporeal blood gases in 6 monkeys before, during, and after erection induced by either papaverine or phentolamine or a combination of the two. Papaverine alone caused a strong erection (maximal tumescence and rigidity) by means of a rapid, large increase in pO2 and pCO2 with a pH drop to the acidic range. Phentolamine alone caused 'delayed' tumescence with less rigidity; the intracorporeal pO2 level increased, but pCO2 and pH values did not change significantly. The combination of both drugs offered no advantage over papaverine alone. We conclude that papaverine is a potent erection-inducing drug that acts in a bimodal manner, namely, it increases the arterial inflow and, at the same time, decreases the venous outflow. Phentolamine affects the arterial component of erectile function only.     

Reduction of sympathetic influences on penile erection by phentolamine

The lumbosacral sympathetic trunks seem to play a major role in penile detumescence. In animal experiments an erection induced by cavernous nerve stimulation can be abolished by neurostimulation of the canine sympathetic trunks. This canine experiment was designed to study the possible reduction of the sympathetic effect by intravenous injection of phentolamine. The aborted erection by sympathetic trunks stimulation was partially antagonized by phentolamine. The arterial flow to the penis as well as the intracavernous pressure were elevated by this drug. As an expected side effect the systemic arterial blood pressure decreased by 4-14 cm H2O after phentolamine injection.     

Hemodynamic study of penile erection in dogs

Full erection by the optimal electrical stimulation of the cavernous nerves was induced in dogs anesthetized with pentobarbital and the hemodynamics of the corpus cavernosum investigated. In 7 dogs, the divided internal pudendal arteries were cannulated and perfused with constant and adjustable arterial inflow. Before nerve stimulation, this increase in flow raised the intracorporeal pressure (ICP). The same change in flow during nerve stimulation resulted in an elevation of ICP. Furthermore, nerve stimulation at zero flow condition elicited a significant increase in ICP. The results suggest that full penile erection requires nerve stimulation during high flow state (constant flow above 25 ml/min). The ICP cannot reach a maximum by passive increase in flow alone. The increase in ICP by nerve stimulation at zero flow condition indicates the existence of a contractile element around the corpus cavernosum or the venous compartment. This mechanism may not be essential for penile erection, but it may serve to change the flow-pressure relationship in the corpus cavernosum.     

降钙素基因相关肽在阴茎勃起机制中的作用

通过实验动物（成年雄性狗）研究肽能神经介质──降钙素基因相关肽（ＣＧＲＰ）在勃起机制中的作用。取动物海绵体平滑肌、阴部内动脉、静脉等组织离体灌注并活体海绵体内注射ＣＧＲＰ，证实对离体组织具有舒张作用，以海绵体平滑肌最强。活体海绵体内注射观察动脉血流量增加，海绵体内压升高，阴茎明显胀大。刺激海绵体神经诱导阴茎勃起检测ＣＧＲＰ水平变化，发现在勃起高峰时，海绵体组织内ＣＧＲＰ增高，面消退期血浆内ＣＧＲＰ升高。从而证实ＣＧＲＰ可导致海绵体平滑肌松弛、减少阻力，增快动脉血流，是促使阴茎勃起的主要神经介质之一。在消退期也可能参与使阻闭静脉的开放，加快回流的作用。     

Intracellular mechanism of penile erection in monkeys

To elucidate the sequence of events between the release of neurotransmitters and cavernous smooth muscle relaxation in erection, we studied the role of the cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) systems. In a well-established simian model, the effects of specific agonists and antagonists of the intracellular sequence for smooth muscle relaxation and potassium channel openers on the intracavernous pressure were examined. Sodium nitroprusside (10^?3 M), a nitric oxide releaser and thus a stimulant of the cGMP system, caused an increase in the intracavernous pressure from 82 to 115 cm H₂O for 7 to 19 min and penile diameter from 24.8 ± 2.28 to 43 ± 4.87 mm. When nitroprusside was injected after methylene blue (10^?3 M), a specific antagonist of the enzyme guanylate cyclase, intracavernous pressure rise decreased significantly, but cromakalin, a potassium channel opener, provoked excellent increases after the block. A smaller dose of sodium nitroprusside (10^?4 M) caused an increase in intracavernous pressure from 35 to 85 cm H₂O for 7 to 11.5 min. When nitroprusside was injected after zaprinast, a phosphodiesterase inhibitor, the increase in pressure ranged from 80 to 116 cm H₂O for 15 to 30 min. Prostaglandin E₁, an activator of the cAMP system, caused an increase in the intracavernous pressure of 20–80 cm H₂O for 5 to 10 min, and an increase in penile diameter from 25 ± 2.22 to 35 ± 3.48 mm. The erectile response to PGE₁, but not to cromakalin, was nearly abolished by ethylmaleimide, an adenylate cyclase blocker. The response to nitroprusside was significantly greater (P < 0.05) than to PGE₁. Both systems. cAMP and cGMP, may be involved in cavernous smooth muscle relaxation, and cGMP is probably the predominant intracellular second messenger in penile erection in monkeys. Stimulants of the cGMP system, such as nitric oxide releasers, could represent a more physiological and effective approach in the treatment of erectile dysfunction. © 1994 Wiley-Liss, Inc.     

Influence of dihydroergotoxine, bromocriptine, and ergotamine on penile erection in wistar rats

The pilot study presented was conducted to determine as to whether ergot alkaloids (alpha-adrenergic blockers) have a potential effect on penile erectile function. The influence of dihydroergotoxine, bromocriptine, and ergotamine was studied on the erection ability in intact, two-grade outbred male Wistar albino rats that were out of their estrous phase. The experimental animals were injected intrapenially with the substances under examination: dihydroergotoxine mesylate (0.1 mg/0.1 mL, 0.3 mg/0.1 mL, and 1 mg/0.1 mL), bromocriptine mesylate (0.3 mg/0.1 mL, 1 mg/0.1 mL, and 3 mg/0.1 mL), and ergotamine tartrate (0.1 mg/0.1 mL, 0.3 mg/0.1 mL, and 1mg/0.1 mL). Every dose was tested on a pattern of 30 rats. These mentioned substances were injected in the amount of 1 mm to the left of the proximal part of the superficial dorsal vein of the penis, in the region of the penis root. After injection, the animals were then observed within the next 90 minutes. In the trial, the following was observed: the number of rats with an erection achieved, the period of time from intrapenial application to the appearance of the first erection, and the duration of the erection. Ultimately, the research results confirm the efficiency of dihydroergotoxine and bromocriptine as erectogenic agents, as well as ergotamine as a detumescent compared with saline solutions.     

Acetylcholine as a possible neurotransmitter in penile erection

We investigated the erectile response to intracavernous injection of increasing doses of acetylcholine (0.5 to 500 micrograms.) in 10 monkeys. To differentiate between nicotinic (ganglionic) and muscarinic (parasympathetic postganglionic) effects, acetylcholine was likewise administered after 1.6 mg. trimethaphan camsylate and 0.1 mg. atropine, alone or sequentially. Erections were induced by cavernous nerve stimulation before and after atropine. Acetylcholine induced a dose-dependent, triphasic erectile response: a first tumescence phase followed by contraction and a subsequent second phase of tumescence. Atropine reduced but did not abolish the erectile response to acetylcholine: attainment of maximal intracavernous pressure after neurostimulation was both delayed and reduced (mean 25 cm. H2O). Only after combined nicotinic and muscarinic blockade was the erectile response to acetylcholine completely abolished. Histologic staining for acetylcholinesterase in five additional monkeys that had not received acetylcholine showed dense staining within the cavernous erectile tissue and around the cavernous arteries. Our data suggest that acetylcholine is a possible neurotransmitter for penile erection in monkeys.     

The surgical treatment of erection disorders caused by penile curvature

The authors report their experience of the surgical management of penis curvature in 26 patients. Eight patients had a congenital curvature due to an asymmetry of the corpus cavernosa and 18 patients had a secondary curvature (La Peyronie's disease : 17, traumatism : 1). The Nesbit procedure alone produces usual excellent results (84.6%). In Peyronie's disease with distal non-erection, a cavernous body prosthesis is recommended.     

Feline penile erection induced by transurethral administration of sodium nitroprusside

Nitric oxide (NO) is an important mediator in the relaxation of cavernosal smooth muscle. The aim of this study was to investigate the in vivo feline erectile response after transurethral administration of sodium nitroprusside (SNP), a NO donor drug. Erectile responses after administration of transurethral SNP were compared with those elicited by an intracavernosal control triple-drug combination (1.65 mg papaverine, 25 μg phentolamine, and 0.5 μg prostaglandin E₁). SNP was administered via a 20-gauge Jelco intravenous catheter in a volume of 200 μl and changes in intracavernosal pressure, penile length, and systemic blood pressure were monitored. The control triple-drug combination was administered via a 30-gauge needle at the end of each experiment to serve as a control reference. Transurethral administration of SNP (1–4 mg) induced penile erection in a dose-dependent manner with minimal changes in systemic blood pressure. The maximum increase in intracavernosal pressure and penile length after transurethral administration of SNP (4 mg) was significantly less than after the intracavernosal injection of the control triple-drug combination (P < 0.01). These data suggest that transurethral administration of SNP can induce an erectile response in cats with minimal side effects. Received: 17 December 1998 / Accepted: 14 April 1999     

会阴肌在阴茎勃起中的作用

以犬为模型对会阴肌在阴茎勃起中的作用进行研究。结果显示阴茎基础海绵体压为：１．１５±０．３５ｋＰａ，单独刺激盆神经时，会阴肌不收缩时阴茎海绵体压为１０．３６±２．３７ｋＰａ。单独刺激阴部神经时，阴茎海绵体压为：３．８±１．１４ｋＰａ。联合刺激二神经，会阴肌收缩最强时阴茎海绵体压可达４６．３３±１６．５２ｋＰａ，阴茎达到硬勃起期，可见会阴肌及阴部神经是增加阴茎勃起硬度的重要因素，盆神经是阴茎勃起的基础。     

法舒地尔对高血压大鼠勃起功能的影响

目的:探讨Rho激酶抑制剂法舒地尔对高血压大鼠勃起功能的影响及其机制。方法:12周龄雄性SD大鼠随机分成对照组(A组)、高血压组(B组)、法舒地尔治疗组(C组),建立高血压大鼠模型后,C组给予法舒地尔[30 mg/(kg.d)]腹腔注射,A组、B组给予等量生理盐水腹腔注射,术后10周测量大鼠阴茎海绵体内压/平均颈动脉压(ICPmax/MAP),Western印迹法测定ROCK1、ROCK2蛋白在阴茎海绵体的表达水平。结果:B组收缩压(mmHg)、ROCK1、ROCK2蛋白表达(190.39±5.07、0.048±0.002、0.143±0.011)较A组(124.81±4.01、0.036±0.001、0.101±0.011)显著增加(P<0.05),C组收缩压(mmHg)、ROCK1、ROCK2蛋白表达(182.03±4.32、0.044±0.001、0.126±0.007)较B组显著降低(P<0.05),B组ICPmax/MAP(36.82±5.47)较A组(59.99±5.69)显著降低(P<0.05),C组(51.1±5.63)较B组显著提高(P<0.05)。结论:法舒地尔可通过抑制RhoA/Rho激酶信号高表达及可能的降血压作用而改善高血压大鼠勃起功能。     

非性交勃起在勃起功能障碍患者阴茎康复中的应用

勃起功能障碍(ED)是临床上常见的一种男科疾病,有研究显示40~70岁的男性ED患病率约52%,且日益趋向年轻化。目前认为,缺氧是ED的独立危险因素,其导致ED的机制复杂多样。近年来,阴茎康复理念备受重视,这一理念的引导实施是通过增加海绵体组织氧供,降低组织纤维化和凋亡以促进勃起功能恢复正常。而针对增加海绵体组织氧供的一些非性交勃起手段,如行为治疗、药物治疗、真空负压吸引装置治疗、海绵体内注射治疗等,可在一定程度上模拟男性正常自然性交勃起,帮助患者进行有效的阴茎康复锻炼。本文就目前非性交勃起治疗在阴茎康复中的应用作一论述。