Application of correlation techniques in the analysis of corpus cavernosum electromyographic signals

Aim： To establish an objective, easy-to-use and comprehensive method to analyze corpus cavernosum electromyo- graphic signals （CC-potentials）. Methods： CC-potentials were recorded during flaccidity in 23 young healthy volunteers, with surface electrodes placed on the penile shaft bilaterally. Based on the correlation function of Matlab software, an application program for the analysis of CC-potentials was developed. Individual CC-potentials and their autocorrelation function were evaluated, yielding parameters amplitude （A）, duration （D）, and dominant frequency （DF）. The crosscorrelation function of both longitudinal and bilateral pairs of adjacent electrodes was calculated to assess the similar- ity and mutual delay of CC-potentials recorded simultaneously from different parts of the CC. The parameters derived were squared maximum cross-correlation coefficient （Rmax） and delay （τ）. Based on the absolute value of τ and the corresponding inter-electrode distance, propagation velocity （PV） was calculated. Results. The values of the parameters were determined automatically. No significant difference related to the locations of the electrodes for parameters A, D, and DF was detected. The cross-correlation showed that both longitudinal and bilateral CC-potential pairs had highly similar waveforms （the absolute values of Rmax were 0.80 ± 0.05 and 0.87 ± 0.06, respectively）. PV of longitudinal pairs was estimated as 6.15 ± 3.98 cm/s. Conclusion： The application program for correlation analysis of CC-potentials is a comprehensive and versatile method to analyze corpus cavernosum electromyographic recordings. Its objectiveness makes multi-center application possible.

Effects of plant extract neferine on cyclic adenosine monophosphate and cyclic guanosine monophosphate levels in rabbit corpus cavernosum in vitro

Aim： To further investigate the relaxation mechanism of neferine （NED, a bis-benzylisoquinoline alkaloid extracted （isolated） from the green seed embryo of Nelumbo nucifera Gaertn in China, on rabbit corpus cavernosum tissue in vitro. Methods： The effects of Nef on the concentrations of cyclic adenosine monophosphate （cAMP） and cyclic guanosine monophosphate （cGMP） in isolated and incubated rabbit corpus cavernosum tissue were recorded using ^125I radioimmunoassay. Results： The basal concentration of cAMP in corpus cavernosum tissue was 5.67 ± 0.97 pmol/mg. Nef increased the cAMP concentration in a dose-dependent manner （P 〈 0.05）, but this effect was not inhibited by an adenylate cyclase inhibitor （cis-N-[2-phenylcyclopentyl]azacyclotridec-1-en-2-amine, MDL-12, 330A） （P 〉 0.05）. The accumulation of cAMP induced by prostaglandin Et （PGEt, a stimulator of cAMP production） was also augmented by Nef in a dose-dependent manner （P 〈 0.05）. The basal concentration of cGMP in corpus cavernosum tissue is 0.44 ± 0.09 pmol/mg. Nef did not affect this concentration of cGMP, either in the presence or in the absence of a guanyl cyclase inhibitor （1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, ODQ） （P 〉 0.05）. Also, sodium nitroprusside （SNP, a stimulator of cGMP production）-induced cGMP production was not enhanced by Nef （P 〉 0.05）. Conclusion： Nef, with its relaxation mechanism, can enhance the concentration of cAMP in rabbit corpus cavernosum tissue, probably by inhibiting phosphodiesterase activity. （Asian JAndro12008 Mar; 10： 307-312）

Ex vivo relaxation effect of Cuscuta chinensis extract on rabbit corpus cavernosum

The effect of Cuscuta chinensis extract on the rabbit penile corpus cavernosum （PCC） was evaluated in the present study. Penises obtained from healthy male New Zealand white rabbits （2.5-3.0 kg） were precontracted with phenylephrine （Phe, 10 pmol I^-1） and then treated with various concentrations of Cuscuta chinensis extract （1, 2, 3, 4 and 5 mg ml^-1）. The change in penile tension was recorded, and cyclic nucleotides in the PCC were measured by radioimmunoassay （RIA）. The interaction between Cuscuta chinensis and sildenafil was also evaluated. The result indicated that the PCC relaxation induced by Cuscuta chinensis extract was concentration-dependent. Pre-treatment with an nitric oxide synthase （NOS） inhibitor （No〉 nitro-L-arginine-methyl ester, L-NAME）, a guanylyl cyclase inhibitor （1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-l-one, ODQ）, or a protein kinase A inhibitor （KT 5720） did not completely inhibit the relaxation. Incubation of penile cavernous tissue with the Cuscuta chinensis extract significantly increased cyclic guanosine monophosphate （cGMP） and cyclic adenosine monophosphate （cAMP） in the PCC. Moreover, the Cuscuta chinensis extract significantly enhanced sildenafil-induced PCC relaxation. In conclusion, the Cuscuta chinensis extract exerts a relaxing effect on penile cavernous tissue in part by activating the NO-cGMP pathway, and it may improve erectile dysfunction （ED）, which does not completely respond to sildenafil citrate.

Effect of sodium nitroprusside on hemodynamics of corpus cavernosum in Chinese

Aim: To study the effect of sodium nitroprusside (SNP) on the hemodynamics of corpus cavemosum in Chinese menwith erectile dysfunction (ED). Methods; In 68 ED patients receiving intracavemous injection (ICI) of SNP, thecavernous hemodynamics were studied by Doppler ultrasonography. Results: The peak flow velocity (PFV), theartery diameter (Ad), the mean velocity of arterial blood (MV) and the vein diameter (Vd) were significantly higherafter ICI of SNP than before ICI, but the end diastolic velocity (EDV) did not change significantly. Conclusion;The increase in Vd after SNP suggests that the venous outflow is not invariably decreased during penile erection.(Asian J Androl 2001 Dec; 3: 311 - 313)

Effects of Ligustrazine on the Contraction of Isolated Rabbit Corpus Cavernosum Strips

Summary： To investigate the role of ligustrazine on relaxation of the isolated rabbit corpus cavernosum tissue in vitro, the effects of ligustrazine on the corpus cavernosum were observed by using experimental method of smooth muscle strips. Concentration-responses to phenylephine （PE） and KCI were recorded. The results showed that ligustrazine concentration-dependently depressed the contraction response of smooth muscle strips induced by PE. The maximum percentage relaxation of cavernosal strips by ligustrazine was 74.1±6.2 % （compared with control： 21.9±5.6%, P〈0.01）. Ligustrazine concentration-dependently reduced the amplitude of the contraction induced by cumulative doses of PE or KCI, shifted the cumulative concentration response curves of PE and KCI to the right and depressed their maximal responses. It was concluded that ligustrazine could significantly relax the cavernosal muscle contraction induced by PE in vitro. The results suggested that ligustrazine inhibited calcium ion influx.

Testosterone replacement maintains smooth muscle content in the corpus cavernosum of orchiectomized rats

Objective:To evaluate the effects of testosterone(T)on the maintenance of corpus cavernosum(CC)structure and apoptosis.Methods:Animals were divided into three groups:sham operation group(n Z 8)underwent sham operation;Orchiectomized(Orchiec)t oily vehicle group(n Z 8)underwent bilateral orchiectomy and received a single dose of oily vehicle by intramuscular injection(i.m.)30 days after orchiectomy;and Orchiec t T group(n Z 8)underwent bilateral orchiectomy and received a single dose of T undecanoate 100 mg/kg i.m.30 days after the surgery.Animals were euthanized 60 days after the beginning of the experiment with an anesthetic overdose of ketamine and xylazine.Blood samples and penile tissue were collected on euthanasia.

Effect of Berberine on the mRNA Expression of Nitric Oxide Synthase(NOS) in Rat Corpus Cavernosum

Summary: In order to further investigate the mechanisms of action of berberine (Ber), we assessed the effects of Ber on the mRNA expression of nitric oxide synthases (NOS) in rat corpus cavernosum. After incubation with Ber for 1 or 3 h respectively, the levels of NOS mRNA were examined by reverse transcription polymerase chain reaction (RT-PCR). Our results showed that there were iNOS and eNOS mRNA expressions in rat corpus cavernosum. Ber enhanced eNOS mRNA expression in rat penis, but exhibited no effect on the expression of iNOS mRNA (P>0.05). The present study indicated that the relaxation of Ber involved the NO-cGMP signal thansduction pathway. The enhancing effect of Ber on eNOS mRNA expression might associated with its relaxation of corpus cavernosum.

Three-dimensional mapping and comparative analysis of the distal human corpus cavernosum and the inflatable penile prosthesis

The intricate anatomy of the corpus cavernosum in both the flaccid and tumescent state has not been fully elucidated. We report our experience using a three-dimensional （3D） scanner to reconstruct cadaveric casts and compare them with 3D images of two prototypes of penile prosthesis. Two different models of the Titan Coloplast inflatable penile prosthesis were analyzed using a 3D scanner. The first was the standard model and the second was a newer model with a rounder silicone tip. Two cadaveric phalluses were harvested using Smooth-Cast 300Q polyurethane molding. The molds were excised and scanned along side the penile prosthesis. 3D scans were completed and analyzed using Leios Mesh software, and GOM Inspect software. The 3D scans demonstrated the mean human corporal radii 2 mm from the distal tip to be 36.51 mm （36.01-37.0 mm）, which is an obtuse angle. The standard Titan penile prosthesis spherical radius at the same level was 202.52 mm, while the new silicone tip prosthesis had a radius of 139.33 mm. 3D mapping further demonstrated the trajectory of the cavernosa appeared curvilinear and the distal ends appeared blunt. The use of cadaveric cavernosal molds in combination with the 3D scanner allowed us to accurately image the corpus cavernosum for the first time. Our findings suggest that anatomically accurate corporal tips appear to be relatively blunt and that the new Titan silicone tip penile prosthesis more closely resembles the human corporal tip.

A Rare Presentation of Partial Segmental Thrombosis of the Corpus Cavernosum Secondary to Sickle Cell Anemia

Background: Partial segmental thrombosis of the corpus cavernosum, known as partial priapism, is an uncommon urological condition which predominantly affects young men in which the proximal part of one corpus cavernosum is thrombosed. Many risk factors have been described in the literature, however, the exact etiology of penile thrombosis and its pathogenesis remains unclear. Several treatment options are available ranging from conservative medical treatment, surgical intervention, or simple follow-up observation without treatment. Aim: In this study, we describe a patient with sickle cell anemia who presented with pain and a perineal swelling that was eventually diagnosed as partial priapism utilizing MRI scan and was treated conservatively with a successful outcome. We then performed a literature search of similar cases highlighting incidence, risk factors and management of this rare presentation. Case Presentation: A 23-year-old male who is known with sickle cell anemia presented to casualty with a 1-day history of perineal pain of a sudden onset associated with perineal swelling and vomiting. Genitourinary exam findings confirmed the absence of classic priapism. Careful examination of his perineal area revealed the presence of a fixed, hard, and tender mass at the proximal part of the penis. It was not attached to the overlying skin and no enlarged pelvic lymph nodes were felt. Once stabilized, MRI of the pelvis was performed showing right intra-tunical corpus cavernosum features suggestive of hematoma in keeping with partial segmental thrombosis of the corpus cavernosum. Conservative treatment was initiated, and the patient was managed expectantly in which he improved gradually with eventual disappearance of the perineal mass. Conclusion: Partial segmental thrombosis of the corpus cavernosum is a rare urological condition. Pathogenesis and etiologies are poorly understood but risk factors have been advocated of which sickle cell anemia is one of them. MRI has a crucial role in the diagnosis under this condition. Conservative treatment appears to be a reliable initial therapeutic option.

Effects of buried penis on the structure and function of corpus cavernosum in a rat model

Background While the abnormal appearance of the concealed penis has been well recognized, the effect of buried penis on the structure and function of corpus cavernosum has not been well studied. To explore this issue, we established a rat model and evaluated the effect of buried penis on cavernosum weight, contents and ultrastructure of tissue, and nitric oxide synthase （NOS） activity. Methods Two hundred and ten rats were randomly divided into 3 equal cohorts for 2, 4 and 6 months study （groups A, B and C）. Each group was randomly divided into buried group （n=40）, control group （n=15）, and normal group （n=15）, respectively. Intra-purse-string suture of the root of the penis was used to establish the model. Macroscopic development was judged by measuring the weight of the corpus cavernosum. Masson＇s trichrome staining was performed for observing microstructure while a transmission electron microscope was used for observing ultrastructure. The NOS activity was detected by a NOS activity assay kit. Results Buried penis had no significant influence on the appearance and weight of the corpus cavernosum. Buried penis resulted in decreased smooth muscle content （P 〉0.05 in group A, and P 〈0.05 in groups B and C） and increased fibrous connective tissue content （P 〉0.05 in groups A and B, and P 〈0.05 in group C） compared with the normal and control groups. Ultrastructural abnormalities of corpus cavernosum were observed in the 6-month buried group. Moreover, there was decrease of NOS activity in groups B and C （P 〈0.05 in group B and P 〈0.01 in group C） when compared with the normal and control groups. Conclusion Buried penis affects the structure and function of corpus cavernosum in rats and the effect is positively correlated with the buried time, but there is no significant effect on the macroscopic development.

Quantitative assessment of the aging corpus cavernosum by shear wave elastography

We wanted to determine whether shear wave elastography(SwE)could be used to evaluate the aging degree of the corpus cavernosum(CC)and to identify the histological basis of changes in SWE measurements during the aging process.We performed a crosssectional study enrolling healthy participants of different ages.We measured the Young's modulus(YM)of the penile CCs by SWE and assessed erectile function using the International Index of Erectile Function-5(IIEF-5).Histological investigation was performed in surgically resected penile specimens from a separate group of patients to examine the smooth muscle and collagen content of the CCs.Furthermore,we measured the YM,erectile function,smooth muscle,and collagen content of the CCs in different age groups of rats.Finally,we enrolled 210 male volunteers in this study.The YM of the CC(CCYM)was positively correlated with age(r=0.949,P<0.01)and negatively correlated with erectile function(r=-0.843,P<0.01).Histological examinations showed that cCs had increased collagen content but decreased smooth muscle content with increased age.The same positive correlation between CcYM and age was also observed in the animal study.In addition,the animal study showed that older rats,with increased CcYM and decreased erectile function,had lower smooth muscle content and higher collagen content.SwE can noninvasively and quantitatively evaluate the aging degree of the Cc.Increased collagen content and decreased smooth muscle content might be the histological basis for the effect of aging on the CC and the increase in its YM.

Relaxation mechanisms of cavernosum tissue in vitro neferine on the rabbit corpus

Aim： To investigate the relaxation mechanisms of neferine （Nef） on the rabbit corpus cavemosum tissue in vitro. Methods： Strips of rabbit corpus cavemosum were mounted in organ chambers. The effects of Nef were examined on isolated muscle strips precontracted with phenylephrine （PE） alone, in the presence of NW-nitro-L-arginine （LNNA, a nitric oxide synthase inhibitor）, 1-H-[ 1,2,4]oxadiazolo[4,3-tx]quinoxalin- 1-one （ODQ, a guanylyl cyclase inhibitor）, indomethacin （cyclooxygenase inhibitor）, tetraethylammonium （Ca^2＋ -activated K^＋ channel blocker）, 4-aminopiridine （4-AP ,voltage dependent K^＋ channel blocker） and glibenclamide （ATP sensitive K^＋channel blocker）. The effects of Nef on KCl-induced contraction of isolated muscle strips were also investigated. The procedure of calcium absencecalcium addition was designed to observe the effect of Nef on two components of the contractile responses to PE based on the source of Ca^2＋ （extracellular vs. intracellular）. Results： Corpus cavemosum strips relaxed in response to Nef （10-9-10-4 mol/L） in a concentration-dependent manner with an IC50 of 4.60 × 10^-6 mol/L. However, they were not affected by LNNA, ODQ, indomethacin or K^＋-channel blockers. Nef （10^-6 mol/L, 10^-5 mol/L） concentration dependently reduced the maximal contraction response of isolated strips induced by KC1 to 79.3% ± 5.5% and 61.5% ±3.2%, respectively （P 〈 0.01）. In the calcium absence-calcium addition procedure, Nef 10.5 mol/L inhibited both intracellular calcium-dependent and extracellular calcium-dependent contraction induced by PE （2 × 10^5 mol/L） （P 〈 0.05）. The inhibition ratios were 26.2% ± 5.4% and 48.3% ±7.6%, respectively. Conclusion： The results of the present study suggest that Nef possesses a relaxant effect on rabbit corpus cavemosum tissues, which is attributable to the inhibition of extracellular Ca^2＋ influx and the inhibition of release of intracellular stored Ca^2＋, but not mediated by the release of nitric oxide, prostaglandins or by the activation of potassium channels.

Effects of aqueous leaf extract of Tridax procumbens on contractile activity of corpus cavernosum in N-nitro-L-arginine methyl ester-induced hypertensive male rats

Objective： This study investigated the effects of aqueous leaf extract of Tridax procumbens （ALETP） on con- tractile activity of corpus cavernosum in N-nitro-L-arginine methyl ester （L-NAME）-induced hypertensive male rats. Methods： Twenty normal, adult male rats （130-150 g） were divided into four groups of five rats each. Group I （control） was given normal saline （0.6 mL/kg） and group II was given L-NAME （40 mg/kg） for 6 weeks. Groups Ill and IV also received L-NAME （40 mg/kg） for 6 weeks but were further co-treated with 100 and 200 mg/kg of ALETP, respectively, from week 4 to week 6. All treatments were given orally. Strips of corpus cavernosum from each of the four groups were exposed to increasing concentrations of acetyl~ choline （ACh） and sodium nitroprusside （SNP） （10^-9-10^-5 tool/L） after contraction with phenylephrine （10^-7 mol/L） to test for a dose-response effect, Response to potassium and calcium was also measured after cumulatively adding potassium and calcium （10-50 mmol/L） to potassium- and calcium-free organ chamber. Isometric contractions were recorded through an Ugo Basile data capsule acquisition system. Results： Mean arterial blood pressure was significantly reduced in the ALETP co-treated group compared to the control and L-NAME-only groups （P 〈 0.05）. Cavernosa strips from ALETP co-treated rats exhibited significant inhibition of contraction in response to phenylephrine, potassium chloride, and calcium chlo- ride （P 〈 0.05）. Relaxation in response to Ach and SNP was also significantly impaired in cavernosa strips from the L-NAME-only treated group （P 〈 0.05）, while ALETP co-treated groups showed enhanced per- centage relaxation. Conclusion： ALETP treatment of L-NAME-induced hypertensive rats promotes a relaxant effect on isolated cavernosa strips. ALETP shows potential in correcting erectile dysfunction in hypertension.

Artificial cavernosa-like tissue based on multibubble Matrigel and a human corpus cavernous fibroblast scaffold

Ex vivo tissue culture of the human corpus cavernosum(cc)can be used to explore the tissue structural changes and complex signaling networks.At present,artificial Cc-like tissues based on acellular or three-dimensional(3D)-printed scaffolds are used to solve the scarcity of primary penis tissue samples.However,inconvenience and high costs limit the wide application of such methods.Here,we describe a simple,fast,and economical method of constructing artificial CC-like tissue.Human Cc fibroblasts(FBs),endothelial cells(ECs),and smooth muscle cells(SMCs)were expanded in vitro and mixed with Matrigel in specific proportions.A large number of bubbles were formed in the mixture by vortexing combined with pipette blowing,creating a porous,spongy,and spatial structure.The Cc FBs produced a variety of signaling factors,showed multidirectional differentiation potential,and grew in a 3D grid in Matrigel,which is necessary for CC-like tissue to maintain a porous structure as a cell scaffold.Within the C-like tissue,ECs covered the surface of the lumen,and SMCs were located inside the trabeculae,similar to the structure of the primary Cc.Various cell components remained stable for 3 days in vitro,but the EC content decreased on the 7th day.Wingless/integrated(WNT)signaling activation led to lumen atrophy and increased tissue fibrosis in CC-like tissue,inducing the same changes in characteristics as in the primary Cc.This study describes a preparation method for human artificial cC-like tissue that may provide an improved experimental platform for exploring the function and structure of the cC and conducting drug screening for erectile dysfunction therapy.

Recent insights into androgen action on the anatomical and physiological substrate of penile erection

Erectile response is centrally and peripherally regulated by androgens. The original insights into the mechanisms of action of androgens were that androgens particularly exert effects on libido and that erections in response to erotic stimuli were relatively androgen-independent. It was shown that sexual functions in men required androgen levels at the low end of reference values of testosterone. So it seemed that testosterone was not useful treatment for men with erectile difficulties, particularly following the advent of the phosphodiesterase type 5 （PDE5） inhibitors. However, approximately 50% of those treated with PDE5 inhibitors discontinue their treatment. A number of recent developments shed new light on testosterone treatment of erectile dysfunction （ED） in aging men. （1） A recent insight is that, in contrast to younger men, elderly men might require higher levels of testosterone for normal sexual functioning. （2） Several studies have indicated that PDE5 inhibitors are not always sufficient to restore erectile potency in men, and that testosterone improves the therapeutical response to PDE5 inhibitors considerably. （3） There is growing insight that testosterone has profound effects on tissues of the penis involved in the mechanism of erection and that testosterone deficiency impairs the anatomical and physiological substrate of erectile capacity, reversible upon androgen replacement. The synthesis of PDE5 is upregulated by androgens, and the arterial inflow into the penis is improved by giving androgen. The above invites a re-examination of the merits of giving testosterone to aging men with ED. The beneficial effects of PDE5 inhibitors may only be optimally expressed in a eugonadal environment. （Asian J Androl 2006 Jan; 8： 3-9）

Apoptosis in rat erectile tissue induced by castration

Aim: To investigate the effect of androgen on the structure of corpus cavernosum. Methods: Thirty mature rats wererandomized into 3 groups, i.e., simple castration, castration with testosterone (T) supplementation and sham-operatedcontrols. One week after operation, the animals were sacrificed and corpora cavenosa harvested. Apoptosis was detect-ed with the in situ end labeling (ISEL) techniques and DNA fragment analysis. Results: The apoptotic rate was4.19 % in the simple castrated rats, 0.2 % in castrated rats supplemented with T and 0.14 % in the controls. Signifi-cant difference was found between the simple castrates and other two groups (P < 0.01). When comparing the T-sup-plementation group with the controls, there was no statistical difference (P > 0.05). Conclusion: Castration inducedapoptosis in rat corpus cavernosum, that could be prevented by T supplementation. It suggests that androgen plays animportant role in maintaining the structure of corpus cavernosum. (Asian J Androl 1999 Dec; 1: 181-185)

Energy restriction and exercise modulate angiopoietins and vascular endothelial growth factor expression in the cavernous tissue of high-fat diet-fed rats

The purpose of the current study was to evaluate the effect of a high-fat （HF） diet, energy restriction and exercise on the expression of vascular endothelial growth factor （VEGF）, angiopoietin （Ang） I and 2, and their receptors in rat corpus cavernosum （CC）. Male Wistar rats were fed adlibitum with an H F diet for 8 or 16 weeks. After 8 weeks of the H F diet, a group of rats was subjected to energy restriction with or without exercise for 8 weeks. Control animals had free access to standard diet for the same period. After euthanasia, blood was collected and the penises removed for immunofluorescence assays （VEGF, VEGF receptor （VEGFR） I and 2, Angl, Ang2 and Tie2） and semiquantification of VEGF, VEGFR 1, VEGFR2, Angl, Ang2, Tie2, endothelial nitric oxide synthase （eNOS） and Aktlphospho-Akt by Western blotting. HF diet-fed rats exhibited lower high-density lipoprotein cholesterol （HDL-c） levels, higher systolic blood pressure and an increased atherogenic index. A significant increase in Ang2 expression in the CC was verified and coupled to a decrease in VEGF and VEGFRs. The Akt pathway was activated by the HF diet. Energy restriction and exercise increased eNOS expression and restored most HF diet-induced modifications except for VEGFR2 expression. These results emphasize the role of diet on vascular function regulation, demonstrating that cavernous imbalance of VEGF/VEGFRs and Angs/Tie2 systems occurs before serum lipid changes and obesity onset, antedating structural atherosclerotic features.

Animal models for studying penile hemodynamics

Animal models for the study of erectile function monitoring the changes in intracavernous pressure (ICP) during penile erection was reviewed. The development of new models using small commercially-available experimental animals, rats and mice, in the last decade facilitated in vivo investigation of erectile physiology. The techniqueenabled to evaluate even subtle erectile responses by analyzing ICP and systemic blood pressure. Moreover, the method has been well improved and studies using conscious animal models without the influence of any drug or anesthesia are more appropriate in exploring the precise physiological and pharmacological mechanisms in erection. Also, more natural and physiological sexual arousal instead of electrical or pharmacological stimulation is desirable in most of the studies.This article reviewed the development of ICP studies in rats and mice.

Effect of sildenafil citrate on penile erection of rhesus macaques

Aim: To examine the effect of sildenafil citrate on penile erection of male rhesus macaque. Methods: Twenty Macaca mulatta were divided into the sildenafil treated and the control groups of 10 animals each. The penile size, the corpus cavernosal electromyogram (EMG) and the intra-corpus cavernosal pressure (ICP) were determined. Results: The diameter of penis and the ICP were significantly increased and the corpus cavernosal EMG significantly reduced in the sildenafil group. Conclusion: Sildenafil citrate increases the penile size and ICP and reduces the corpus cavernosal EMG in male rhesus macaque.

体外及体内实验证明高丽参浆果提取物（GB0710）对阴茎勃起的影响

Several reports have promoted the root-derived Korean red ginseng （KRG; Panax ginseng） as alternative treatment for erectile dysfunction （ED）, and ginsenosides are known to be the principal active ingredients of ginseng. Recent studies showed that ginseng berries produce more ginsenosides than KRG; thus, we investigated the ability of the Korean ginseng berry extract GB0710 to relax the penile corpus cavernosum smooth muscle （CCSM） in this study. As a comparative control, the results were compared to those obtained using KRG. In addition, possible mechanisms of action for GB0710 were investigated. While KRG and GB0710 both displayed dose-dependent relaxation effects on precontracted rabbit CCSM in vitro, GB0710 was shown to be more potent than KRG. The GBO710-induced relaxation could be partially reduced by removing the endothelium. In addition, pre-treatment with several nitric oxide （NO） inhibitors significantly inhibited the relaxation of muscle strips. Furthermore, administration of GB0710 increased intracavernosal pressure （ICP） in a rat in vivo model in both a dose- and duration-dependent manner. Intracellular NO production in human microvascular endothelial cells could be induced by GB0710 and inhibited by NG-monomethyI-L-arginine. In conclusion, GB0710 had a greater relaxation effect on rabbit CCSM than did KRG extract, and increased ICP in a rat model in both a dose- and a duration-dependent manner. This relaxine effect might be mediated bv NO production.