Penile anthropometry in systemic lupus erythematosus patients

The aim of this study was to evaluate penile anthropometry in systemic lupus erythematosus (SLE) patients compared with healthy controls and the possible relevant pubertal, clinical, hormonal and treatment factors that could influence penile dimensions. Twenty-five consecutive SLE patients were assessed by urological examination, sexual function, testicular ultrasound, hormones, sperm analysis, genetic analysis, clinical features and treatment. The control group included 25 age-matched healthy males. SLE patients had a lower median penis length and circumference [8 (7.5-10) vs. 10 (8-13) cm, p = 0.0001; 8 (7-10) vs. 10 (7-11) cm, p = 0.001; respectively], lower median testicular volume by right and left Prader [15 (10-25) vs. 20 (12-25) ml, p = 0.003; 15 (10-25) vs. 20 (12-25) ml, p = 0.006; respectively], higher median of follicle-stimulating hormone [5.8 (2.1-25) vs. 3.3 (1.9-9) IU/l, p = 0.002] and lower morning total testosterone levels (28% vs. 0%, p = 0.009) compared with controls. In spite of that, erectile dysfunction was not observed in patients or controls. Analyses of lupus patients revealed that the median penis circumference was lower in patients with disease onset before first ejaculation compared with those with disease onset after first ejaculation [7.8 (7-10) vs. 9.0 (7.5-10) cm, p = 0.026]. No differences were observed in the median penile anthropometry regarding sexual dysfunction (p = 0.610), lower morning total testosterone levels (p = 0.662), oligo/azoospermia (p = 0.705), SLE Disease Activity Index >= 4 (p = 0.562), Systemic Lupus International Collaborating Clinics/ACR Damage Index >= 1 (p = 0.478), prednisone cumulative dose (p = 0.789) and intravenous cyclophosphamide therapy (p = 0.754). Klinefelters syndrome (46XY/47XXY) was diagnosed in one (4%) SLE patient with decreased penile size whereas Y-chromosomal microdeletions was absent in all of them. In conclusion, we have identified reduced penile dimensions in SLE patients with no deleterious effect in erectile function. Disease onset before first ejaculation seems to affect penis development in pre-pubertal lupus. Lupus (2011) 20, 512-518.

Hypoactive sexual desire disorder in a population-based study of Brazilian women: associated factors classified according to their importance

Objective: The etiology of hypoactive sexual desire disorder (HSDD) is known to be multifactorial, involving biological, psychosexual, and context-related factors. The objective of the present study was to analyze the factors associated with female HSDD and to stratify these factors according to their importance. Methods: This was a population-based, hierarchical study conducted in Brazil, based on data from previous research on the Brazilian Sexual Life Study, conducted between November 2002 and February 2003 in various Brazilian cities. The primary study consisted of a self-administered and anonymous questionnaire, addressing sociodemographic parameters, general health, life habits, behavior, and complaints related to sexual function. The association between HSDD and various other factors was assessed. The data were evaluated by hierarchical multiple regression analysis. Results: The prevalence of HSDD in this sample was 9.5%. Associations were found with cardiovascular disease, breast cancer, posttraumatic stress, poorer education level, being older, being married, a lack of information on sexuality in childhood/adolescence, and a limited sexual repertoire. Women who consumed moderate amounts of alcohol were found to be less likely to have HSDD. Conclusions: Analysis of the associated factors classified in order of importance and analysis of the characteristics of the sexual relationships provide additional information to currently available data on the traditional concepts of HSDD.

International Society for Sexual Medicine`s Guidelines for the Diagnosis and Treatment of Premature Ejaculation

Introduction. Over the past 20 years our knowledge of premature ejaculation (PE) has significantly advanced. Specifically, we have witnessed substantial progress in understanding the physiology of ejaculation, clarifying the real prevalence of PE in population-based studies, reconceptualizing the definition and diagnostic criterion of the disorder, assessing the psychosocial impact on patients and partners, designing validated diagnostic and outcome measures, proposing new pharmacologic strategies and examining the efficacy, safety and satisfaction of these new and established therapies. Given the abundance of high level research it seemed like an opportune time for the International Society for Sexual Medicine (ISSM) to promulgate an evidenced-based, comprehensive and practical set of clinical guidelines for the diagnosis and treatment of PE. Aim. Develop clearly worded, practical, evidenced-based recommendations for the diagnosis and treatment of PE for family practice clinicians as well as sexual medicine experts. Method. Review of the literature. Results. This article contains the report of the ISSM PE Guidelines Committee. It affirms the ISSM definition of PE and suggests that the prevalence is considerably lower than previously thought. Evidence-based data regarding biological and psychological etiology of PE are presented, as is population-based statistics on normal ejaculatory latency. Brief assessment procedures are delineated and validated diagnostic and treatment questionnaires are reviewed. Finally, the best practices treatment recommendations are presented to guide clinicians, both familiar and unfamiliar with PE, in facilitating treatment of their patients. Conclusion. Development of guidelines is an evolutionary process that continually reviews data and incorporates the best new research. We expect that ongoing research will lead to a more complete understanding of the pathophysiology as well as new efficacious and safe treatments for this sexual dysfunction. Therefore, it is strongly recommended that these guidelines be re-evaluated and updated by the ISSM every 4 years. Althof SE, Abdo CHN, Dean J, Hackett G, McCabe M, McMahon CG, Rosen RC, Sadovsky R, Waldinger M, Becher E, Broderick GA, Buvat J, Goldstein I, El-Meliegy AI, Giuliano F, Hellstrom WJG, Incrocci L, Jannini EA, Park K, Parish S, Porst H, Rowland D, Segraves R, Sharlip I, Simonelli C, and Tan HM. International Society for Sexual Medicine`s guidelines for the diagnosis and treatment of premature ejaculation. J Sex Med 2010;7:2947-2969.

Timing of Dose Relative to Sexual Intercourse Attempt in Previous Sildenafil Citrate Users Treated with Tadalafil: A Geographical Comparison from a Single Arm, Open-Label Study

Introduction. Previous research has demonstrated that sildenafil citrate users alter dosing-sexual attempt behavior when switched to tadalafil. The impact of geography and culture on sexual behavior with phosphodiesterase type 5 (PDE5) inhibitor treatment has not been fully investigated. Aim. To describe and compare the changes in dosing-sexual attempt behavior with sildenafil citrate vs. tadalafil treatment across four distinct geographies: Asia, Australia/New Zealand (ANZ), Central Eastern Europe/Middle East (CEE/ME), and Latin America (LA). Methods. Data from a single-arm, open-label clinical trial conducted in 21 countries from November 2002 to May 2004 were used in this analysis. Men with erectile dysfunction and a history of >= 6-week prior sildenafil citrate use continued sildenafil citrate treatment for 4 weeks then switched to tadalafil for 8 weeks. Dosing instructions were provided. Main Outcomes Measures. Timing of dose and sexual intercourse was assessed through patient diaries for the final 4 weeks of each treatment period. Results. A total of 2,760 men were enrolled: Asia 15.8%; ANZ 29.4%; CEE/ME 19.7%; LA 35.1%. The median time from dosing to intercourse was significantly increased during tadalafil treatment across all geographical regions; however, the magnitude of increase differed significantly by geography (P < 0.0001). The Asian cohort demonstrated the shortest duration between dosing and sexual intercourse attempts (irrespective of drug), and altered sexual behavior the least upon switching to tadalafil. The ANZ cohort demonstrated the longest duration between dosing and sexual intercourse attempts (irrespective of drug), and altered sexual behavior the most upon switching to tadalafil. Conclusion. Men with a history of established sildenafil citrate use alter their dose-attempt behavior when treated with tadalafil irrespective of geography. However, the extent to which sexual behavior alters is not uniform across geographical regions, suggesting that dosing instructions and duration of drug effectiveness, in combination with personal and cultural preferences, may determine sexual behavior with PDE5 inhibitor use. Rubio-Aurioles E, Glina S, Abdo CHN, Hernandez-Serrano R, Rampazzo C, Sotomayor M, West TM, Gallagher GL, and Lenero E. Timing of dose relative to sexual intercourse attempt in previous sildenafil citrate users treated with tadalafil: A geographical comparison from a single arm, open-label study. J Sex Med 2009;6:2836-2850.

Sildenafil inhibits duodenal contractility via activation of the NO-K+ channel pathway

Phosphodiesterase type-5 (PDE5) specifically cleaves cyclic guanosine monophosphate (cGMP), a key intracellular secondary messenger. The PDE5 inhibitor sildenafil is a well-known vasodilator that also has gastrointestinal myorelaxant properties. In the present study, we further investigated sildenafil-induced myorelaxation in rat isolated duodenum, assessing its interaction with nitric oxide (NO) synthase and K+ channel opening. The spontaneous contractions of duodenal strips were reversibly inhibited by sildenafil (0.1-300 mu M) in a concentration-dependent manner [mean (95% confidence interval); EC50 = 6.8 (2.7-17.3) mu M]. The sildenafil-induced myorelaxation was significantly decreased by the NO synthase inhibitor N-nitro-L-arginine methyl ester [increasing the EC50 value to 41.9 (26.1-67.3) mu M]. Sodium nitroprusside or forskolin pretreatments enhanced the sildenafil-induced myorelaxation. In isolated strips pretreated with BaCl2 (0.2 mM), 4-aminopyridine (4-AP, 3 mM), or glybenclamide (1 mu M), the sildenafil-induced EC50 value was significantly increased to 32.8 (19.1-56.4), 27.1 (15.2-48.3) and 20.1 (16.4-24.7) mu M, respectively. Minoxidil (50 mu M) or diazoxide (100 mu M) also significantly attenuated the sildenafil-induced potency. In conclusion, the NO synthase/cyclic nucleotide pathway activation is involved in sildenafil-induced inhibition of spontaneous duodenal contractions. Its pharmacological action seems to be influenced by K+ channel opening, especially the voltage-sensitive ones, being inhibited by 4-AP and K-ATP channels, sensitive to glybenclamide.

TNF-alpha Infusion Impairs Corpora Cavernosa Reactivity

Introduction. Erectile dysfunction (ED), as well as cardiovascular diseases (CVDs), is associated with endothelial dysfunction and increased levels of proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha). Aim. We hypothesized that increased TNF-alpha levels impair cavernosal function. Methods. In vitro organ bath studies were used to measure cavernosal reactivity in mice infused with vehicle or TNF-alpha-(220 ng/kg/min) for 14 days. Gene expression of nitric oxide synthase isoforms was evaluated by real-time polymerase chain reaction. Results. Cavernosal strips from the TNF-alpha-infused mice displayed decreased nonadrenergic-noncholinergic (NANC)-induced relaxation (59.4 +/- 6.2 vs. control: 76.2 +/- 4.7; 16 Hz) compared with the control animals. These responses were associated with decreased gene expression of eNOS and nNOS (P < 0.05). Sympathetic-mediated, as well as phenylephrine (PE)-induced, contractile responses (PE-induced contraction; 1.32 +/- 0.06 vs. control: 0.9 +/- 0.09, mN) were increased in cavernosal strips from TNF-alpha-infused mice. Additionally, infusion of TNF-alpha increased cavernosal responses to endothelin-1 and endothelin receptor A subtype (ET(A)) receptor expression (P < 0.05) and slightly decreased tumor necrosis factor-alpha receptor 1 (TNFRI) expression (P=0.063). Conclusion. Corpora cavernosa from TNF-alpha-infused mice display increased contractile responses and decreased NANC nerve-mediated relaxation associated with decreased eNOS and nNOS gene expression. There changes may trigger ED and indicate that TNF-alpha plays a detrimental role in erectile function. Blockade of TNF-alpha actions may represent an alternative therapeutic approach for ED, especially in pathologic conditions associated with increased levels of this cytokine. Carneiro FS, Zemse S, Giachini FRC, Carneiro ZN, Lima W, Clinton Webb R, and Tostes RC. TNF-alpha infusion impairs corpora cavernosa reactivity. J Sex Med 2009;6(suppl 3):311-319.

TNF-alpha Knockout Mice Have Increased Corpora Cavernosa Relaxation

Erectile dysfunction is considered an early clinical manifestation of vascular disease and an independent risk factor for cardiovascular events associated with endothelial dysfunction and increased levels of pro-inflammatory cytokines. Tumor necrosis factor-alpha (TNF-alpha), a pro-inflammatory cytokine, suppresses endothelial nitric oxide synthase (eNOS) expression. Considering that nitric oxide (NO) is of critical importance in penile erection, we hypothesized that blockade of TNF-alpha actions would increase cavernosal smooth muscle relaxation. In vitro organ bath studies were used to measure cavernosal reactivity in wild type and TNF-alpha knockout (TNF-alpha KO) mice and NOS expression was evaluated by western blot. In addition, spontaneous erections (in vivo) were evaluated by videomonitoring the animals (30 minutes). Collagen and elastin expression were evaluated by Masson trichrome and Verhoff-van Gieson stain reaction, respectively. Corpora cavernosa from TNF-alpha KO mice exhibited increased NO-dependent relaxation, which was associated with increased eNOS and neuronal NOS (nNOS) cavernosal expression. Cavernosal strips from TNF-alpha KO mice displayed increased endothelium-dependent (97.4 +/- 5.3 vs. Control: 76.3 +/- 6.3, %) and nonadrenergic-noncholinergic (93.3 +/- 3.0 vs. Control: 67.5 +/- 16.0; 16 Hz) relaxation compared to control animals. These responses were associated with increased protein expression of eNOS and nNOS (P < 0.05). Sympathetic-mediated (0.69 +/- 0.16 vs. Control: 1.22 +/- 0.22; 16 Hz) as well as phenylephrine-induced contractile responses (1.6 +/- 0.1 vs. Control: 2.5 +/- 0.1, mN) were attenuated in cavernosal strips from TNF-alpha KO mice. Additionally, corpora cavernosa from TNF-alpha KO mice displayed increased collagen and elastin expression. In vivo experiments demonstrated that TNF-alpha KO mice display increased number of spontaneous erections. Corpora cavernosa from TNF-alpha KO mice display alterations that favor penile tumescence, indicating that TNF-alpha plays a detrimental role in erectile function. A key role for TNF-alpha in mediating endothelial dysfunction in ED is markedly relevant since we now have access to anti-TNF-alpha therapies. Carneiro FS, Sturgis LC, Giachini FRC, Carneiro ZN, Lima VV, Wynne BM, Martin SS, Brands MW, Tostes RC, and Webb RC. TNF-alpha knockout mice have increased corpora cavernosa relaxation. J Sex Med 2009;6:115-125.

Murine and rat cavernosal responses to endothelin-1 and urotensin-II Vasoactive Peptide Symposium

Endothelin-1 (ET-1) and urotensin-II (U-II) are the most potent constrictors of human vessels. Although the cavernosal tissue is highly responsive to ET-1, no information exists on the effects of U-II on cavernosal function. The aim of this study was to characterize ET-1 and U-II responses in corpora cavernosa from rats and mice. Male Wistar rats and C57/BL6 mice were used at 13 weeks. Cumulative concentration-response curves to ET-1, U-II, and IRL-1620, an ET(B) agonist, were performed. ET-1 increased force generation in cavernosal strips from mice and rats, but no response to U-II was observed in the presence or absence of N(omega)-nitro-L-arginine methyl ester (L-NAME), or in strips prestimulated with 20 mM KCI. IRL-1620 did not induce cavernosal contraction even in presence of L-NAME, but induced a cavernosal relaxation that was greater in rats than mice. No relaxation responses to U-II were observed in cavernosal strips precontracted with phenylephrine. mRNA expression of ET-1, ET(A), ET(B), and U-II receptors, but not U-II was observed in cavernosal strips. ET-1, via ET(A) receptors activation, causes contractile responses in cavernosal strips from rats and mice, whereas ET(B) receptor activation produces relaxation. Although the cavernosal tissue expresses U-II receptors, U-II does not induce contractile responses in corpora cavernosa from mice or rats. J Am Soc Hypertens 2008;2(6): 439-447. Published by Elsevier Inc. on behalf of the American Society of Hypertension.

DOCA-salt treatment enhances responses to endothelin-1 in murine corpus cavernosurn

The penis is kept in the flaccid state mainly via a tonic activity of norepinephrine and endothelins (ETs). ET-1 is important in salt-sensitive forms of hypertension. We hypothesized that cavernosal responses to ET-1 are enhanced in deoxycorticosterone acetate (DOCA)-salt mice and that blockade of ETA receptors prevents abnormal responses of the corpus cavernosum in DOCA-salt hypertension. Male C57BL/6 mice were unilaterally nephrectomized and treated for 5 weeks with both DOCA and water containing 1% NaCl and 0.2% KCl. Control mice were uninephrectomized and received tap water with no added salt. Animals received either the ETA antagonist atrasentan (5 mg.day(-1).kg(-1) body weight) or vehicle. DOCA-salt mice displayed increased systolic blood pressure (SBP), and treatment with atrasentan decreased SBP in DOCA-salt mice. Contractile responses in cavernosal strips from DOCA-salt mice were enhanced by ET-1, phenylephrine, and electrical field stimulation (EFS) of adrenergic nerves, whereas relaxations were not altered by IRL-1620 (an ETB agonist), acetylcholine, sodium nitroprusside, and EFS of nonadrenergic noncholinergic nerves. PD59089 (an ERK1/2 inhibitor), but not Y-27632 (a Rho-kinase inhibitor), abolished enhanced contractions to ET-1 in cavernosum from DOCA-salt mice. Treatment of DOCA-salt mice with atrasentan did not normalize cavernosal responses. In summary, DOCA-salt treatment in mice enhances cavernosal reactivity to contractile, but not to relaxant, stimuli, via ET-1/ETA receptor-independent mechanisms.

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

Introduction. Erectile dysfunction (ED) in diabetes is associated with autonomic neuropathy and endothelial dysfunction. Whereas the nonadrenergic-noncholinergic (NANC)/neurogenic nitric oxide pathway has received great attention in diabetes-associated ED, few studies have addressed sympathetic overactivity. Aim. To test the hypothesis that adenosine-induced inhibition of adrenergic-mediated contractile responses in mouse corpus cavernosum is impaired in the presence of diabetes. Methods. The db/db (obesity and type II diabetes caused by a leptin receptor mutation) mouse strain was used as a model of obesity and type II diabetes, and standard procedures were performed to evaluate functional cavernosal responses. Main Outcome Measures. Increased cavernosal responses to sympathetic stimulation in db/db mice are not associated with impaired prejunctional actions of adenosine. Results. Electrical field stimulation (EFS)-, but not phenylephrine (PE)-, induced contractions are enhanced in cavernosal strips from db/db mice in comparison with those from lean littermates. Direct effects of adenosine, 2-chloro-adenosine, A(1) receptor agonist C-8031 (N6 cyclopentyladenosine), and sodium nitroprusside are similar between the strips from lean and db/db mice, whereas relaxant responses to acetylcholine and NANC stimulation are significantly impaired in the cavernosal strips from db/db mice. 5`-Iodotubercidin (adenosine kinase inhibitor) and dipyridamole (inhibitor of adenosine transport), as well as the A(1) agonist C-8031, significantly and similarly inhibit contractions induced by stimulation of adrenergic nerves in the cavernosal strips from lean and db/db mice. Conclusions. Results from this study suggest that corpora cavernosa from obese and diabetic db/db mice display altered neural-mediated responses that would favor penile detumescence, i.e., increased contractile response to adrenergic nerve stimulation and decreased relaxant responses upon activation of NANC nerves. However, increased cavernosal responses to adrenergic nerve stimulation are not due to impaired negative modulation of sympathetic neurotransmission by adenosine in this diabetic model.

Internal Pudendal Artery from Type 2 Diabetic Female Rats Demonstrate Elevated Endothelin-1-Mediated Constriction

Introduction. Diabetes is a risk factor for female sexual dysfunction (FSD). FSD has several etiologies, including a vasculogenic component that could be exacerbated in diabetes. The internal pudendal artery supplies blood to the vagina and clitoris and diabetes-associated functional abnormalities in this vascular bed may contribute to FSD. Aim. The Goto-Kakizaki (GK) rat is a non-obese model of type 2 diabetes with elevated endothelin-1 (ET-1) activity. We hypothesize that female GK rats have diminished sexual responses and that the internal pudendal arteries demonstrate increased ET-1 constrictor sensitivity. Methods. Female Wistar and GK rats were used. Apomorphine (APO)-mediated genital vasocongestive arousal (GVA) was measured. Functional contraction (ET-1 and phenylephrine) and relaxation (acetylcholine, ACh) in the presence or absence of the ETA receptor antagonist (ET(A)R; atrasentan) or Rho-kinase inhibitor (Y-27632) were assessed in the internal pudendal and mesenteric arteries. Protein expression of ET-1 and RhoA/Rho-kinase signaling pathway was determined in the internal pudendal and mesenteric arteries. Main Outcome Measure. APO-mediated GVAs; contraction and relaxation of internal pudendal and mesenteric arteries; ET-1/RhoA/Rho-kinase protein expression. Results. GK rats demonstrated no APO-induced GVAs. Internal pudendal arteries, but not mesenteric arteries, from GK rats exhibited greater contractile sensitivity to ET-1 compared with Wistar arteries. ETAR blockade reduced ET-1-mediated constriction in GK internal pudendal and mesenteric arteries. Rho-kinase inhibition reduced ET-1-mediated constriction of GK internal pudendal but not mesenteric arteries; however, it had no effect on arteries from Wistar rats. RhoA protein expression was elevated in GK internal pudendal arteries. At the highest concentrations, ACh-mediated relaxation was greater in the GK internal pudendal artery; however, no difference was observed in the mesenteric artery. Conclusions. Female GK rats demonstrate decreased sexual responses that may be because of increased constrictor sensitivity to the ET-1/RhoA/Rho-kinase signaling in the internal pudendal artery. Allahdadi KJ, Hannan JL, Ergul A, Tostes RC, and Webb RC. Internal pudendal artery from type 2 diabetic female rats demonstrate elevated endothelin-1-mediated constriction. J Sex Med 2011;8:2472-2483.

Nitric Oxide-Induced Vasorelaxation in Response to PnTx2-6 Toxin from Phoneutria nigriventer Spider in Rat Cavernosal Tissue

Introduction. Priapism is one of several symptoms observed in accidental bites by the spider Phoneutria nigriventer. The venom of this spider is comprised of many toxins, and the majority has been shown to affect excitable ion channels, mainly sodium (Na+) channels. It has been demonstrated that PnTx2-6, a peptide extracted from the venom of P. nigriventer, causes erection in anesthetized rats and mice. Aim. We investigated the mechanism by which PnTx2-6 evokes relaxation in rat corpus cavernosum. Main Outcome Measures. PnTx2-6 toxin potentiates nitric oxide (NO)-dependent cavernosal relaxation. Methods. Rat cavernosal strips were incubated with bretylium (3 x 10-5 M) and contracted with phenylephrine (PE; 10-5 M). Relaxation responses were evoked by electrical field stimulation (EFS) or sodium nitroprusside (SNP) before and after 4 minutes of incubation with PnTx2-6 (10-8 M). The effect of PnTx2-6 on relaxation induced by EFS was also tested in the presence of atropine (10-6 M), a muscarinic receptor antagonist, N-type Ca2+ channel blockers (omega-conotoxin GVIA, 10-6 M) and sildenafil (3 x 10-8 M). Technetium99m radiolabeled PnTx2-6 subcutaneous injection was administrated in the penis. Results. Whereas relaxation induced by SNP was not affected by PnTx2-6, EFS-induced relaxation was significantly potentiated by this toxin as well as PnTx2-6 plus SNP. This potentiating effect was further increased by sildenafil, not altered by atropine, however was completely blocked by the N-type Ca2+ channels. High concentrated levels of radiolabeled PnTx2-6 was specifically found in the cavernosum tissue, suggesting PnTx2-6 is an important toxin responsible for P. nigriventer spider accident-induced priapism. Conclusion. We show that PnTx2-6 slows Na+ channels inactivation in nitrergic neurons, allowing Ca2+ influx to facilitate NO/cGMP signalling, which promotes increased NO production. In addition, this relaxation effect is independent of phosphodiesterase enzyme type 5 inhibition. Our data displays PnTx2-6 as possible pharmacological tool to study alternative treatments for erectile dysfunction. Nunes KP, Cordeiro MN, Richardson M, Borges MN, Diniz SOF, Cardoso VN, Tostes R, De Lima ME, Webb RC, and Leite R. Nitric oxide-induced vasorelaxation in response to PnTx2-6 toxin from Phoneutria nigriventer spider in rat cavernosal tissue. J Sex Med 2010;7:3879-3888.

Endothelin-1 Induces Contraction of Female Rat Internal Pudendal and Clitoral Arteries through ET(A) Receptor and Rho-Kinase Activation

Introduction. Endothelin-1 (ET-1), a potent vasoconstrictor peptide, acts mainly through the Gprotein-coupled ET(A) receptor (ET(A)R). Increased vascular ET-1 production and constrictor sensitivity have been observed in various cardiovascular diseases, including hypertension, as well as erectile dysfunction. The internal pudendal artery (IPA) supplies blood to the vagina and clitoris. Inadequate blood flow through the IPA may lead to insufficient vaginal engorgement and clitoral tumescence. Aim. Characterize the effects of ET-1 on the IPA and clitoral artery (CA). Methods. IPA and CA from female Sprague Dawley rats (225-250 g) were mounted in myograph chambers. Arterial segments were submitted to increasing concentrations of ET-1 (10-10-10-6 M). Segments were incubated with the ET(A)R antagonist, atrasentan (10-8 M) or the Rho-kinase inhibitor, Y-27632 (10-6 M) 30 minutes prior to agonist exposure. All E(max) values are expressed as % KCl-induced maximal contraction. ET(A)R, RhoA, and Rho-kinase expression from IPA was evaluated by Western blot. mRNA of preproET-1, ET(A)R, ET(B)R, RhoA, and Rho-kinase were measured by real time PCR. Main Outcome Measures. ET-1 constrictor sensitivity in IPA and CA, protein expression and messenger RNA levels of ET-1-mediated constriction components. Results. ET-1 concentration-dependently contracted IPA (% Contraction and pD2, respectively: 156 +/- 18, 8.2 +/- 0.1) and CA (163 +/- 12, 8.8 +/- 0.08), while ET(A)R antagonism reduced ET-1-mediated contraction (IPA: 104 +/- 23, 6.4 +/- 0.2; CA: 112 +/- 17, 6.6 +/- 0.08). Pretreatment with Y-27632 significantly shifted ET-1 pD2 in IPA (108 +/- 24, 7.9 +/- 0.1) and CA (147 +/- 58 and 8.0 +/- 0.25). Protein expression of ET(A)R, ET(B)R, RhoA, and Rho-kinase were detected in IPA. IPA and CA contained preproET-1, ET(A)R, ET(B)R, RhoA, and Rho-kinase message. Conclusion. We observed that the IPA and CA are sensitive to ET-1, signaling through the ET(A)R and Rho-kinase pathway. These data indicate that ET-1 may play a role in vaginal and clitoral blood flow and may be important in pathologies where ET-1 levels are elevated. Allahdadi KJ, Hannan JL, Tostes RC, and Webb RC. Endothelin-1 induces contraction of female rat internal pudendal and clitoral arteries through ETA receptor and Rho-kinase activation. J Sex Med 2010;7:2096-2103.

O-GlcNAcylation Contributes to Augmented Vascular Reactivity Induced by Endothelin 1

O-GlcNAcylation augments vascular contractile responses, and O-GlcNAc-proteins are increased in the vasculature of deoxycorticosterone-acetate salt rats. Because endothelin 1 (ET-1) plays a major role in vascular dysfunction associated with salt-sensitive forms of hypertension, we hypothesized that ET-1-induced changes in vascular contractile responses are mediated by O-GlcNAc modification of proteins. Incubation of rat aortas with ET-1 (0.1 mu mol/L) produced a time-dependent increase in O-GlcNAc levels and decreased expression of O-GlcNAc transferase and beta-N-acetylglucosaminidase, key enzymes in the O-GlcNAcylation process. Overnight treatment of aortas with ET-1 increased phenylephrine vasoconstriction (maximal effect [in moles]: 19 +/- 5 versus 11 +/- 2 vehicle). ET-1 effects were not observed when vessels were previously instilled with anti-O-GlcNAc transferase antibody or after incubation with an O-GlcNAc transferase inhibitor (3-[2-adamantanylethyl]-2-[{4-chlorophenyl}azamethylene]-4-oxo-1,3-thiazaperhyd roine-6-carboxylic acid; 100 mu mol/L). Aortas from deoxycorticosterone-acetate salt rats, which exhibit increased prepro-ET-1, displayed increased contractions to phenylephrine and augmented levels of O-GlcNAc proteins. Treatment of deoxycorticosterone-acetate salt rats with an endothelin A antagonist abrogated augmented vascular levels of O-GlcNAc and prevented increased phenylephrine vasoconstriction. Aortas from rats chronically infused with low doses of ET-1 (2 pmol/kg per minute) exhibited increased O-GlcNAc proteins and enhanced phenylephrine responses (maximal effect [in moles]: 18 +/- 2 versus 10 +/- 3 control). These changes are similar to those induced by O-(2-acetamido-2-deoxy-D-glucopyranosylidene) amino-N-phenylcarbamate, an inhibitor of beta-N-acetylglucosaminidase. Systolic blood pressure (in millimeters of mercury) was similar between control and ET-1-infused rats (117 +/- 3 versus 123 +/- 4 mm Hg; respectively). We conclude that ET-1 indeed augments O-GlcNAc levels and that this modification contributes to the vascular changes induced by this peptide. Increased vascular O-GlcNAcylation by ET-1 may represent a mechanism for hypertension-associated vascular dysfunction or other pathological conditions associated with increased levels of ET-1. (Hypertension. 2010; 55: 180-188.)

Impaired Vasodilator Activity in Deoxycorticosterone Acetate-Salt Hypertension Is Associated With Increased Protein O-GlcNAcylation

Hyperglycemia, which increases O-linked beta-N-acetylglucosamine (O-GlcNAc) proteins, leads to changes in vascular reactivity. Because vascular dysfunction is a key feature of arterial hypertension, we hypothesized that vessels from deoxycorticosterone acetate and salt (DOCA-salt) rats exhibit increased O-GlcNAc proteins, which is associated with increased reactivity to constrictor stimuli. Aortas from DOCA rats exhibited increased contraction to phenylephrine (E(max) [mN] = 17.6 +/- 4 versus 10.7 +/- 2 control; n = 6) and decreased relaxation to acetylcholine (47.6 +/- 6% versus 73.2 +/- 10% control; n = 8) versus arteries from uninephrectomized rats. O- GlcNAc protein content was increased in aortas from DOCA rats (arbitrary units = 3.8 +/- 0.3 versus 2.3 +/- 0.3 control; n = 5). PugNAc (O- GlcNAcase inhibitor; 100 mu mol/L; 24 hours) increased vascular O- GlcNAc proteins, augmented phenylephrine vascular reactivity (18.2 +/- 2 versus 10.7 +/- 3 vehicle; n = 6), and decreased acetylcholine dilation in uninephrectomized (41.4 +/- 6 versus 73.2 +/- 3 vehicle; n = 6) but not in DOCA rats (phenylephrine, 16.5 +/- 3 versus 18.6 +/- 3 vehicle, n = 6; acetylcholine, 44.7 +/- 8 versus 47.6 +/- 7 vehicle, n = 6). PugNAc did not change total vascular endothelial nitric oxide synthase levels, but reduced endothelial nitric oxide synthase(Ser-1177) and Akt(Ser-473) phosphorylation (P < 0.05). Aortas from DOCA rats also exhibited decreased levels of endothelial nitric oxide synthase(Ser-1177) and Akt(Ser-473) (P < 0.05) but no changes in total endothelial nitric oxide synthase or Akt. Vascular O-GlcNAc-modified endothelial nitric oxide synthase was increased in DOCA rats. Blood glucose was similar in DOCA and uninephrectomized rats. Expression of O- GlcNAc transferase, glutamine: fructose-6-phosphate amidotransferase, and O- GlcNAcase, enzymes that directly modulate O-GlcNAcylation, was decreased in arteries from DOCA rats (P < 0.05). This is the first study showing that O-GlcNAcylation modulates vascular reactivity in normoglycemic conditions and that vascular O- GlcNAc proteins are increased in DOCA-salt hypertension. Modulation of increased vascular O-GlcNAcylation may represent a novel therapeutic approach in mineralocorticoid hypertension. (Hypertension. 2009; 53: 166-174.)