Corpus Cavernosum Smooth Muscle Research Articles

Gaseous signal molecule hydrogen sulfide and penile erection

Endogenous hydrogen sulfide is the third gaseous signal molecule after nitric oxide and carbon monoxide;it is synthesized through cystathionine-β-synthase and cystathionine-γ-cleavage pathway.Hydrogen sulfide can directly react with the KATP channel,reduce extracellular Ca2+ influx,and work together with testosterone,nitric oxide,carbon monoxide,relaxing corpus cavernosum smooth muscle and improving diastolic function of blood vessels.It can also inhibit vascular smooth muscle cell proliferation,promote apoptosis,and improve vascular remodeling.Therefore,in-depth study of H2S in the regulating penile erection can provide a new way for the treatment of erectile dysfunction.

Insulin-like Growth Factor-1 Gene Delivery May Enhance the Proliferation of Human Corpus Cavernosal Smooth Muscle Cells

To investigate the effects of IGF-1 gene transfer in human corpus cavernosal smooth muscle cells (HCCSMCs) ex vivo. Insulin-like growth factor-1 (IGF-1) promotes the proliferation of penile cavernous smooth muscle cells in the rats. A plasmid expressing human IGF-1 was constructed by subcloning hIGF-1 into pcDNA3.1 vector. HCCSMCs were harvested from 3 impotent patients and cultured in vitro. The cultured smooth muscle cells were identified by immunofluorescent staining. RNA was extracted from HCCSMCs, and the gene expression of IGF-1 was determined by reverse transcription-polymerase chain reaction. Cell growth was examined by use of a novel cell proliferation assay based on the bioreduction of the fluorescent dye Alamar blue. The subcloned product was transfected into HCCSMCs. Western blotting and immunoassay were performed 2 days after transfection to evaluate the transfection efficiency. Endogenous IGF-1 mRNA expression was detected by reverse transcription-polymerase chain reaction analysis of total RNA extracted from cultured HCCSMCs. Increased proliferation of HCCSMCs in vitro was observed with exogenous treatment with IGF-1 (100 ng/mL) in a dose-dependent manner. Exogenous IGF-1 gene transfer to cultured HCCSMCs enhanced IGF-1 protein expression compared with the control, and the expression level peaked at 4 days after transfection and decreased slowly thereafter. Secretion of IGF-1 from transfected HCCSMCs induced cellular proliferation. IGF-1 gene transfer into HCCSMCs enhanced cellular proliferation, which was mediated by secretion of IGF-1. Our results suggest that IGF-1 gene therapy may be applied to corpus cavernosum regeneration.

Paroxetine inhibited the relaxations induced by EFS in mice corpus cavernosum: is it a NOS inhibition?

Selective serotonin reuptake inhibitors are used in the treatment of psychiatric disorders but are associated with high incidence of sexual dysfunction such as ejaculation disorders by sertraline and fluoxetine, erection disorders by paroxetine. The aim of this study is to evaluate the effects of paroxetine, sertraline and fluoxetine on relaxation of smooth muscle of corpus cavernosum on the basis of nitric oxide (NO). Male mice were killed by cervical dislocation and their penile tissues were immediately removed. The tissues were incubated in organ baths containing Krebs solution at 37 degrees C and bubbled with 95% O(2) and 5% CO(2). The corpus cavernosum strips were contracted with 10(-5 )m phenylephrine (PHE) and relaxed with either paroxetine, sertraline, fluoxetine (10(-8)-10(-4 )m) or electrical field stimulation (EFS). The effects of paroxetine, sertraline and fluoxetine were examined on EFS-induced relaxations. While paroxetine did not show any effect on the corpus cavernosum strips precontracted with PHE, sertraline and fluoxetine caused a relaxation at concentrations of 3 x 10(-5)-10(-4 )m. The relaxations induced by sertraline and fluoxetine were completely abolished by L-NAME, but not D-NAME. The relaxations induced by EFS could be inhibited by L-NAME but not D-NAME. Paroxetine inhibited the relaxations at high concentrations. L-arginine potentiated the relaxations induced by EFS; however in the presence of paroxetine these relaxations were not observed. In contrast, sertraline (10(-8)-10(-5 )m) and fluoxetine (10(-8)-10(-5)m) increased the relaxations induced by EFS. Sertraline and fluoxetine seem to be releasing some relaxing factor(s) and this factor may be NO. Paroxetine probably has a NOS inhibitory activity either on nNOS or eNOS, in contrast to sertraline and fluoxetine.

Direct Effect of Carbon Monoxide on Relaxation Induced by Electrical Field Stimulation in Rat Corpus Cavernosum

PurposeCarbon monoxide (CO) may mediate smooth muscle relaxation in the rat corpus cavernosum smooth muscle (CCSM). We hypothesized that CO plays a role in neurally derived, frequency-dependent relaxation of rat CCSM.Materials and MethodsTo study the effect of CO on CCSM relaxation induced by electrical field stimulation (EFS), a CCSM bundle was mounted on a force transducer and perfused with Hanks' balanced salt solution at 37℃ with 95% O2 and 5% CO2. After 1 hour equilibration with -500 mg of passive tension, contraction of the CCSM bundle was elicited by 10-5 M phenylephrine, which was continuously added with different concentrations of CO (1%, 2%, and 5%). Frequency-dependent relaxation was induced by EFS trains (0.2 ms at 0.5-32 Hz, for 10 s) repeated at 2 min intervals over 15 min in the presence of adrenergic and muscarinic receptor blocking agents (guanethidine and atropine, respectively). To study the distribution of heme oxygenase-2 (HO-2) in the rat CCSM, we performed immunohistochemical evaluation.ResultsCO produced a dose-dependent enhancement of EFS-induced relaxation. Pretreatment with NG-nitro-L-arginine (a nitric oxide synthase blocker) greatly reduced the EFS-induced relaxation in the presence of CO (-45%). Pretreatment with zinc protoporphyrin-IX (ZnPP-9, a heme oxygenase inhibitor) had no significant effect on EFS-induced relaxation in the absence or the presence of CO. We found immunoreactivity for HO-2 in CCSM and immunoreactivity for protein gene product 9.5 (PGP 9.5) in nerve fibers.ConclusionsWe conclude that CO produced a dose-dependent enhancement of EFS-induced relaxation in rat CCSM bundles, but neurally derived, frequency-dependent relaxation in the rat CCSM depended mostly on nitric oxide in response to nonadrenergic noncholinergic neurotransmission. Immunoreactivity for HO-2 was found in rat CCSM but not nerve fibers.

Changes in the neurogenic and endothelium-dependent relaxant responses of rabbit corpus cavernosum smooth muscle after cavernous nerve neurotomy

The present study was conducted to investigate the reactivity of the corpus cavernosum smooth muscle after unilateral cavernous nerve neurotomy in rabbits. Rabbits (18) were randomly divided into two groups: sham-operated (n = 9) and those subjected to unilateral neurotomy of a 5-mm segment of the cavernous nerve (n = 9). The reactivity of the corpus cavernosum tissue from the neurotomized and sham groups was studied in organ chambers at 4 weeks postoperation. In the neurotomized group, endothelium-dependent relaxation of the corpus cavernosum smooth muscle to carbachol was significantly increased when compared to the sham group. In addition, the sensitivity (i.e., pD(2)) of neurotomized strips to carbachol was also increased when compared to controls. Electrical field stimulation-induced neurogenic relaxation was significantly reduced in the neurotomized group. Relaxation to the nitric oxide (NO) donor sodium nitroprusside and to papaverine was similar in the cavernosal tissue of both groups. There was no change in agonist potency. Furthermore, neurotomy had no effect on KCl-induced contractile responses. When tissue contraction was induced with phenylephrine to study relaxation to various stimuli, the tension induced was similar in the neurotomized and the sham control groups. We conclude that unilateral, chronic cavernous nerve neurotomy causes significant functional changes to the penile erectile tissue of rabbits, which may contribute to the development of impotence.

Chuanxiongzine relaxes isolated corpus cavernosum strips and raises intracavernous pressure in rabbits

It has been shown that there are many Chinese traditional herbals that can enhance sexual activity. Chuanxiongzine is a vasoactive ingredient that has been isolated and purified from Ligusticum chuanxiong Hort. In previous studies, it has been found that chuanxiongzine was effective in relaxing rabbit corpus cavernosum smooth muscle. We determined the effects of chuanxiongzine on relaxation of isolated corpus cavernosum strips in vitro and on increase of intracavernous pressure (ICP) in vivo in rabbits. Chuanxiongzine caused a concentration-dependent relaxation of phenylephrine precontracted isolated corpus cavernosum strips (EC50 1.58 × 10−4 mol l−1), which were endothelium independent and NO independent. However, the guanylyl cyclase inhibitor 1-H-[1,2,4] oxadiazolo [4,3-a] quinoxalin-1-one significantly shifted the chuanxiongzine concentration–response relationship to the right. Although there was no significant difference in the level of cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) in isolated corpus cavernosum strips treated with chuanxiongzine or vehicle, chuanxiongzine caused a significant rise in the level of cGMP and cAMP in isolated corpus cavernosum strips pretreated with the activator of adenylyl cyclase forskolin and the source of NO sodium nitroprusside. In an in vivo study, chuanxiongzine dose-dependently raised ICP after the intracavernous injection of its cumulative doses (0.5, 1, 2 and 5 mg kg−1). The ICP increased from baseline to 19.1±3.7, 24.8±2.1, 30.2±4.8 and 39.7±6.1 mm Hg, respectively, and the duration of tumescence ranged from 8.5±2.8 to 22.9±7.3 min. Our results show that chuanxiongzine can relax isolated corpus cavernosum strips of rabbits in vitro and increase ICP of rabbits in vivo, which is neither endothelium dependent nor NO dependent, but may be partly mediated by the inhibition of cAMP phosphodiesterase or cGMP phosphodiesterase.

NS11021, a novel opener of large‐conductance Ca2+‐activated K+ channels, enhances erectile responses in rats

Large-conductance Ca(2+)-activated K(+) channels (BK(Ca)), located on the arterial and corporal smooth muscle, are potential targets for treatment of erectile dysfunction (ED). This study investigated whether NS11021 (1-(3,5-Bis-trifluoromethyl-phenyl)-3-[4-bromo-2-(1H-tetrazol-5-yl)-phenyl]-thiourea), a novel opener of BK(Ca) channels, relaxes erectile tissue in vitro and enhances erectile responses in intact rats. The effects were compared with sildenafil, an inhibitor of phosphodiesterase type 5. Patch clamp was used to record whole cell current in rat isolated corpus cavernosum smooth muscle cells (SMCs) and human umbilical vein endothelial cells (HUVECs). Isometric tension was measured in intracavernous arterial rings and corpus cavernosum strips isolated from rats and men, and simultaneous measurements of intracellular Ca(2+) concentration ([Ca(2+)](i)) and tension were performed in intracavernous arteries. Erectile response was measured in anaesthetized rats. In patch clamp recordings, NS11021 increased currents sensitive to the selective BK(Ca) channel blocker, iberiotoxin (IbTX) in SMCs, but did not modulate K(+) current in HUVECs. NS11021 reduced [Ca(2+)](i) and tension in penile arteries. IbTX inhibited the vasorelaxation induced by NS11021 and sildenafil in human erectile tissue. NS11021 and sildenafil but not vehicle increased erectile responses in anaesthetized rats, an effect which was abolished after pretreatment with tetraethylammonium. NS11021 leads to relaxation of both intracavernous arteries and corpus cavernosum strips primarily through opening of BK(Ca) channels. It is also effective in facilitating erectile responses in anaesthetized rats. These results suggest a potential for use of BK(Ca) openers in the treatment of ED.

In Vitro and In Vivo Relaxation of Corpus Cavernosum Smooth Muscle by the Selective Myosin II Inhibitor, Blebbistatin

Blebbistatin (BLEB) is a small cell permeable molecule originally reported as a selective inhibitor of myosin II isoforms expressed by striated muscle and non-muscle cells (IC(50) = 0.5-5 microM) with poor inhibition of turkey gizzard smooth muscle (SM) myosin II (IC(50) approximately 80 microM). However, recently it was found that BLEB can potently inhibit mammalian arterial SM (IC(50) approximately 5 microM). To investigate the effect of BLEB on corpus cavernosum SM (CCSM) tone and erectile function (EF). CC tissue obtained from penile implant patients along with CC, aorta and bladder from adult male rats were used for BLEB organ bath studies. Intracavernosal BLEB was administered to rats and EF was assessed via intracavernous pressure (ICP). Effects of BLEB on agonist-induced CCSM, aorta and bladder contraction in vitro and ICP in vivo. BLEB completely relaxed human CCSM pre-contracted with phenylephrine (PE) in a dose-dependent manner decreasing tension by 76.5% at 10 microM. BLEB pre-incubation attenuated PE-induced contraction of human CC by approximately 85%. Human CC strips pre-contracted with endothelin-1 or KCl were almost completely relaxed by BLEB. Rat CCSM pre-contracted with PE showed BLEB relaxation comparable to human CCSM. BLEB inhibition was similar for rat aorta but slower for bladder. Both maximal ICP and ICP/mean arterial pressure were dose-dependently increased by BLEB intracavernous injections with full erection at 1 micromole. Our novel data reveals that BLEB nearly completely relaxes rat and human CCSM pre-contracted with a variety of potent agonists and exhibits tissue selectivity. Coupled with our in vivo data in which nanomole doses of BLEB significantly increase ICP, our data substantiates an important role for the SM contractile apparatus in the molecular mechanism for EF and suggests the possibility of BLEB binding at myosin II as a therapeutic treatment for ED by targeting SM contractile pathways.

Characterization of Erectile Function in Monocrotaline‐Treated Pulmonary Hypertensive Rats

The aim of this study was to evaluate erectile function in monocrotaline (MCT)-treated rats with pulmonary hypertension (PH). Forty rats were divided into control (n = 20) and MCT-treated (n = 20) groups. Rats were treated with MCT (60 mg/kg subcutaneously) for 3 weeks to induce PH. Mean pulmonary arterial pressure (mPAP), medial hypertrophy index (percentage of wall thickness of pulmonary artery), and right ventricular hypertrophy (ratio of right ventricle [RV] to left ventricle + septum weight) were evaluated. In vivo erectile responses were assessed by measurement of intracavernosal pressure (ICP)/mean arterial pressure and total ICP (area under the curve). In vitro organ bath studies with corpus cavernosum smooth muscle strips were performed under both normoxic (95% O(2)/5% CO(2)) and hypoxic (by changing gas mixture to 95% N(2)/5% CO(2)) conditions. Erectile tissue was processed for immunohistochemistry. The MCT-treated group was associated with an increase in mPAP, medial hypertrophy index, and RV hypertrophy. MCT-induced PH rats had significantly reduced erectile responses compared with controls. Nitrergic, endothelium-dependent relaxations, as well as alpha-adrenergic contractile responses were significantly reduced in the corpus cavernosum of MCT rats. The functional responses during prolonged periods of hypoxia were similar to those observed in MCT-treated tissues. PH rats showed enhanced inducible nitric oxide synthase (NOS) protein localization, but endothelial NOS and neuronal NOS were unchanged. These results suggest changes in cavernosal physiology are caused by MCT acting on the penile tissues and the systemic vasculature.

Construction of cavernosum smooth muscle using umbilical artery smooth muscle cells seeded on acellular corporal collagen matrices

The objective of this study was to investigate the feasibility of tissue engineering of corpus cavernosal smooth muscle. Acellular corporal collagen matrices (ACCMs) were obtained from the penis of adult rabbits by a cell removal procedure. ACCMs were implanted into the back muscles of allogenic rabbits to investigate the resulting immunological reaction. Human umbilical artery smooth muscle cells (HUASMCs) were isolated from human umbilical arteries through explant techniques and expanded in vitro. Subsequently, third and fifth passage HUASMCs were seeded to ACCMs at a concentration of 30 x 10(6) cells/mL. Then, seeded ACCMs were implanted subcutaneously in athymic mice. The implants were retrieved at 10, 20 and 40 days after implantation. Histochemistry, immunohistochemistry and scanning electron microscopy were performed to analyse the morphological characteristics of the engineered tissues. Additionally, organ bath studies were performed to address the contractility of the engineered tissues. The decellularization process successfully extracted all cellular components while preserving the original collagen fibers. The immunological reaction to ACCMs consisted of only a transient nonspecific inflammatory response. Light and scanning electron microscopy demonstrated that HUASMCs extended onto the three-dimensional ACCMs scaffolds in vitro. Histological analyses of the explants from all time points demonstrated a progressive regeneration of smooth muscle, with structures very similar to native corpus cavernosum smooth muscle. The maximum contraction force induced by phenylephrine and electrical stimulation were 3.64 +/- 0.18 g/100 mg and 2.50 +/- 0.21 g/100 mg, respectively. Our study demonstrates that HUASMCs can be seeded on three-dimensional ACCM scaffolds and will develop tissues similar to that of the native corpus cavernosum smooth muscle.

Morphometric and molecular study of corpus cavernosum of the rat after longterm high-fat diet intake

AbstractErectile dysfunction (ED) is considered equivalent to endothelial dysfunction and thus an early manifestation of atherosclerosis and cardiovascular disease (CVD). Atherosclerosis that is frequently provoked by regular consumption of high-fat diet (HFD) has been recently recognized as a chronic inflammation condition associated to vessel lipid deposition and vascular smooth cells proliferation that together impair endothelium-dependent relaxation of corpus cavernosum (CC) smooth muscle. It is also well established that HFD regular intake by its own induces endothelial dysfunction. The main objective of this study was to evaluate effects of HFD continuous intake on atherosclerosis progression of CC vessels of the rat. Due to their intervention on atherosclerosisrelated vascular remodelling pathways, angiopoietins (Ang1, Ang2) expression in erectile tissue of this rat experimental model was characterized.

Expression and function of ryanodine receptors in rabbit penile corpus cavernosum smooth muscle cells

This study aimed to investigate the expression and function of ryanodine receptors (RyRs) in rabbit penile corpus cavernosum smooth muscle (CCSM) cells. New Zealand white rabbit CCSM cells were cultured by primary tissue culture and identified by immunofluorescence technique. mRNA of three RyRs subunits in cultured CCSM cells was detected by reverse transcription polymerase chain reaction (RT-PCR). After excitation by noradrenaline, the concentration of Ca(2+) in CCSM cells was detected by laser scanning confocal microscopy. It was found that only the RyRs1 subunit is expressed in CCSM by RT-PCR. The CCSM cells were divided into two groups: Group A, CCSM cells + 10 micromol l(-1) noradrenaline and Group B, CCSM cells + 50 micromol l(-1) procaine 10 micromol l(-1) noradrenaline. Compared with the base level and the level after noradrenaline excitation, fluorescence intensity improved 44.10 +/- 6.01% in the test group A (n = 8) and 32.92 +/- 4.92% (n = 8) in the procaine control group B, respectively. There were statistically significant differences between group A and group B (P < 0.01). It is concluded that RyRs1 subunit is expressed in CCSM cells and may contribute to regulating the cytoplasmic Ca(2+) level.

Contractility of Diabetic Human Corpus Cavernosum Smooth Muscle in Response to Serotonin Mediated via Rho-Kinase

Background/Aims: Serotonin (5-hydroxytryptamine, 5-HT)-induced contraction and the involvement of RhoA/Rho-kinase pathway in the 5-HT-induced contraction was investigated isometrically in vitro in both diabetic and nondiabetic human corpus cavernosum (HCC) tissues. Methods: HCC tissues were obtained from 12 patients. The response to 5-HT (10^–9 to 10^–5 mol/l) was studied in isolated HCC tissues in the absence and in the presence of a Rho-kinase inhibitor (Y-27632). Results: Preincubation with Y-27632 attenuated maximum contractions induced by 5-HT in tissues of both nondiabetics and diabetics. When diabetic and nondiabetic groups were compared, no significant difference was seen in 5-HT-induced contraction alone, but in the presence of Y-27632, 5-HT-induced contraction was significantly higher in the diabetic group. Conclusion: These results suggest that the Rho-kinase-mediated pathway plays an important role for 5-HT-induced contraction in diabetic corpus cavernosum tissues.

The role and structure of a postradical prostatectomy penile rehabilitation program

Erectile dysfunction (ED) is common after radical prostatectomy (RP). ED has a negative impact on health-related quality of life. Penile rehabilitation is defined as the use of any drug or device at or after RP to maximize erectile function recovery. The purpose of penile rehabilitation is the prevention of corpus cavernosal smooth muscle structural alterations not only to maximize the chances of a man having recovery of functional erections but also returning him to his preoperative erectile function level. Appreciating the value of penile rehabilitation requires understanding five concepts: the pathophysiology of ED after RP, cavernosal oxygenation, venous leak, and both the animal and human data supporting this strategy. This paper gives an overview of these factors and attempts to give a common-sense, practical guide to a rehabilitation program.

Spontaneous Ca2+ Waves in Rabbit Corpus Cavernosum: Modulation by Nitric Oxide and cGMP

Detumescent tone and subsequent relaxation by nitric oxide (NO) are essential processes that determine the erectile state of the penis. Despite this, the mechanisms involved are incompletely understood. It is often assumed that the tone is associated with a sustained high cytosolic Ca(2+) level in the corpus cavernosum smooth muscle cells, however, an alternative possibility is that oscillatory Ca(2+) signals regulate tone, and erection occurs as a result of inhibition of Ca(2+) oscillations by NO. The aim of this study is to determine if smooth muscle cells displayed spontaneous Ca(2+) oscillations and, if so, whether these were regulated by NO. Male New Zealand white rabbits were euthanized and smooth muscle cells were isolated by enzymatic dispersal for confocal imaging of intracellular Ca(2+) (using fluo-4AM) and patch clamp recording of spontaneous membrane currents. Thin tissue slices were also loaded with fluo-4AM for live imaging of Ca(2+). Cytosolic Ca(2+) was measured in isolated smooth muscle cells and tissue slices. Results. Isolated rabbit corpus cavernosum smooth muscle cells developed spontaneous Ca(2+) waves that spread at a mean velocity of 65 microm/s. Dual voltage clamp/confocal recordings revealed that each of the Ca(2+) waves was associated with an inward current typical of the Ca(2+)-activated Cl(-) currents developed by these cells. The waves depended on an intact sarcoplasmic reticulum Ca(2+) store, as they were blocked by cyclopiazonic acid (Calbiochem, San Diego, CA, USA) and agents that interfere with ryanodine receptors and IP(3)-mediated Ca(2+) release. The waves were also inhibited by an NO donor (diethylamine NO; Tocris Bioscience, Bristol, Avon, UK), 3-(5-hydroxymethyl-2-furyl)-1-benzyl indazole (YC-1) (Alexis Biochemicals, Bingham, Notts, UK), 8-bromo-cyclic guanosine mono-phosphate (Tocris), and sildenafil (Viagra, Pfizer, Sandwich, Kent, UK). Regular Ca(2+) oscillations were also observed in whole tissue slices where they were clearly seen to precede contraction. This activity was also markedly inhibited by sildenafil, suggesting that it was under NO regulation. These results provide a new basis for understanding detumescent tone in the corpus cavernosum and its inhibition by NO.

Role of MLCP in relaxation of rat cavernosal smooth muscle

Calyculin A, a direct inhibitor of myosin light chain phosphatase (MLCP), was used to investigate the role of MLCP in mediating nitric oxide (NO)‐induced relaxation in rat corpus cavernosal smooth muscle. Isometric tension of rat cavernosal tissue was recorded and analyzed during contraction and relaxation in vitro. Strips of corpus cavernosum were placed in water‐jacketed tissue chambers filled with physiological buffered saline solution at 37oC and attached to force transducers. The buffer was continuously bubbled with 95% O2, 5% CO2 to maintain oxygenation and pH. After a 1 hour equilibration period, tissue samples were contracted by the addition of norepinephrine (10−4M) followed twenty minutes later by Calyculin A (10−6M) or dimethyl sulfoxide (DMSO, 10−5M) to experimental or control groups, respectively. Tissues were relaxed by adding the NO donor, sodium nitroprusside (SNP, 10−3M). Data were collected using the PolyVIEW data acquisition and analysis software system (Astro Med, Inc.). Results demonstrated that Calyculin A significantly inhibited SNP‐induced relaxation in corpus cavernosum (p &lt; 0.001). Furthermore, the data suggest that MLCP plays a critical role in mediating the cellular mechanisms that regulate relaxation of corpus cavernosal tissue.Supported by the Department of Biological Sciences, YSU.

Management of Erectile Function by Penile Purinergic P2 Receptors in the Diabetic Rat

We determined the role of purine and pyrimidine nucleotides in erectile function in diabetic rats. A total of 60 adult male rats were divided into 2 groups, including 30 controls and 30 treated with streptozotocin (60 mg/kg) for 8 weeks to induce hyperglycemia. Changes in intracavernous pressure after intracrural injections of adenosine 5'triphosphate and adenosine 5'triphosphate analogues in control and diabetic rats, and the relaxant response to electrical field stimulation of precontracted corpus cavernosum smooth muscle in organ baths were investigated. The localization of P2X1, P2Y1 and P2Y2 receptors was assessed in penile tissue via an immunohistochemical approach. Corpus cavernosum smooth muscle relaxation in vivo and by electrical field stimulation in vitro was significantly decreased in diabetic rats. Adenosine 5'triphosphate (P2X, P2Y), 2-methylthioadenosine 5'triphosphate (P2Y1) and uridine 5'-triphosphate (P2Y2) agonists but not alpha,beta-methylene adenosine 5'triphosphate (a P2X1 agonist) significantly improved the erectile response to electrical field stimulation in diabetic rat corpus cavernosum smooth muscle. Although intracavernous pressure/mean arterial pressure values in the rats were not restored in the presence of the P2X1 antagonist PPADS, the relaxation response to electrical field stimulation in isolated corpus cavernosum smooth muscle from diabetic rats was improved. Abundant immunoreactivity for PX1 and P2Y2 receptors was observed in penile tissues from diabetic rats compared to that from control rats. These results demonstrate 1) heterogeneous effects of purinergic agonists on corporeal function in diabetic rats, and 2) the activation of P2Y1 and P2Y2 receptor relaxation of corpus cavernosum smooth muscle to induce erection in rats and perhaps improve erectile function in men with diabetes.

TRANSCRIPTION FACTOR NF-κB MEDIATES THE GENE EXPRESSION OF PROTEINS INVOLVED IN THE REGULATION OF CALCIUM SENSITIZATION PATHWAY IN PARTIAL BLADDER OUTLET OBSTRUCTION IN MICE

Growing clinical evidence suggests that benign prostatic hyperplasia induced partial bladder outlet obstruction is associated with an increased incidence of erectile dysfunction. We determined whether corpus cavernosum smooth muscle from rabbits with partial bladder outlet obstruction show any molecular or functional differences versus controls.Force generation and relaxation of corpus cavernosum smooth muscle 2 weeks after partial bladder outlet obstruction by 125 mM. KCl, phenylephrine and field stimulation were determined. Expression of total smooth muscle myosin and alternatively spliced smooth muscle myosin isoforms were determined by reverse transcriptase-polymerase chain reaction (RT-PCR), quantitative competitive RT-PCR, sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot analysis. Corpus cavernosum smooth muscle from sections of the penis were analyzed morphologically by immunofluorescence microscopy using antibodies to smooth muscle myosin and neurofilament protein.Corpus cavernosum smooth muscle from rabbits with partial bladder outlet obstruction generated 40% to 50% more force than that of sham operated rabbits in response to KCl or phenylephrine and was more difficult to relax. Although quantitative competitive RT-PCR and sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that corpus cavernosum smooth muscle from rabbits with partial bladder outlet obstruction expressed only slightly more total smooth muscle myosin at the messenger RNA and protein levels, expression of the high adenosine triphosphatase isoform SM-B increased 2-fold. Morphological examination of corpus cavernosum smooth muscle sections revealed decreased innervation and increased smooth muscle bundle size.We present the novel finding of molecular and functional changes in the corpus cavernosum smooth muscle associated with partial bladder outlet obstruction. Although the inclusion of sham operation ruled out direct injury during surgery, a change in corpus cavernosum smooth muscle innervation induced by nerve compression by the ligature is likely to induce trophic changes in the corpus cavernosum smooth muscle leading to over expression of the SM-B smooth muscle myosin isoform, increased contractility and impaired relaxation.

INCREASED CORPUS CAVERNOSUM SMOOTH MUSCLE TONE ASSOCIATED WITH PARTIAL BLADDER OUTLET OBSTRUCTION IS MEDIATED VIA NEUROFILAMENT 200 AND APOPTOSIS

You have accessJournal of Urology1 Apr 2009INCREASED CORPUS CAVERNOSUM SMOOTH MUSCLE TONE ASSOCIATED WITH PARTIAL BLADDER OUTLET OBSTRUCTION IS MEDIATED VIA NEUROFILAMENT 200 AND APOPTOSIS Ki Ho Kim, Jung Dam Kim, and Young Jin Seo Ki Ho KimKi Ho Kim More articles by this author , Jung Dam KimJung Dam Kim More articles by this author , and Young Jin SeoYoung Jin Seo More articles by this author View All Author Informationhttps://doi.org/10.1016/S0022-5347(09)60695-9AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail "INCREASED CORPUS CAVERNOSUM SMOOTH MUSCLE TONE ASSOCIATED WITH PARTIAL BLADDER OUTLET OBSTRUCTION IS MEDIATED VIA NEUROFILAMENT 200 AND APOPTOSIS." The Journal of Urology, 181(4S), p. 244 © 2009 by American Urological AssociationFiguresReferencesRelatedDetails Volume 181Issue 4SApril 2009Page: 244 Advertisement Copyright & Permissions© 2009 by American Urological AssociationMetricsAuthor Information Ki Ho Kim More articles by this author Jung Dam Kim More articles by this author Young Jin Seo More articles by this author Expand All Advertisement PDF downloadLoading ...

A NOVEL CLINICAL ENTITY OF OBSTRUCTIVE AZOOSPERMIA: PHENOTYPIC ANALYSIS OF TESTICULAR GERM CELL-SPECIFIC GENE MEICHROACDIN-DISRUPTED MICE AND GENOTYPIC ANALYSIS OF HUMAN MEICHROACIDIN IN MALE INFERTILE POPULATION

Phosphodiesterase type 5 (PDE5) inhibitors are very effective agents for erectile dysfunction; however, specific patient populations are hard to treat. The efficacy of PDE5 inhibitors is limited because a minimum amount of nitric oxide (NO) is necessary. Resveratrol, a plant polyphenol, is reported to activate endothelial NO synthase (eNOS) through activation of sirtuin 1. We previously reported that human corpus cavernosal smooth muscle cells (CCSMCs) express eNOS and synthesize cyclic guanosine monophosphate (cGMP) via the NO/cGMP pathway.To investigate the ability of resveratrol and/or vardenafil to increase cGMP in an in vitro model using CCSMCs and to improve erectile function in an in vivo rat model of streptozotocin (STZ)‐induced diabetes.CCSMCs were treated with resveratrol and/or vardenafil. Twenty male Sprague‐Dawley rats were randomly divided into five groups (N = 4 in each group): age‐matched controls, diabetic controls, and diabetic rats treated with resveratrol, vardenafil, or both in combination for the last 4 weeks of an 8‐week period of diabetes induction.Intracellular cGMP measurement, intracovernous pressure (ICP)/mean arterial pressure (MAP) ratio, and smooth muscle/collagen ratio.Intracellular cGMP level was elevated by resveratrol treatment in CCSMCs. The combination treatment of resveratrol and vardenafil had a synergistic effect. Diabetic rats showed impairment of erectile function. Treatment with either resveratrol or vardenafil improved ICP/MAP ratio, and combination therapy with resveratrol and vardenafil had a synergistic effect in improvement of ICP/MAP.Treatment with either resveratrol or vardenafil elevated cGMP level in CCSMCs and improved erectile function in STZ‐induced diabetic rats. Furthermore, a synergistic effect was observed in vitro and in vivo. Resveratrol or combination therapy of resveratrol and vardenafil can improve erectile function in which NO release is impaired, although further study is needed to confirm the results. Fukuhara S, Tsujimura A, Okuda H, Yamamoto K, Takao T, Miyagawa Y, Nonomura N, and Okuyama A. Vardenafil and resveratrol synergistically enhance the nitric oxide/cyclic guanosine monophosphate pathway in corpus cavernosal smooth muscle cells and its therapeutic potential for erectile dysfunction in the streptozotocin‐induced diabetic rat: Preliminary findings.