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Irwin Goldstein

Publications and source records attributed to Irwin Goldstein.

At least 55 records · Page 3Linked to original sources
PubMed2004

An in vivo rat model to investigate female vaginal arousal response.

PURPOSE: We established a rat model to investigate the female vaginal arousal response and the role of the nitric oxide (NO) pathway on vaginal blood flow in vivo. MATERIALS AND METHODS: Vaginal blood flow changes induced by pelvic nerve stimulation (PNS) in female Sprague-Dawley rats were determined by laser Doppler flowmetry. Frequency response data were determined in each animal. In addition, changes in vaginal blood flow were measured after intravenous administration of the NO synthase inhibitor L-NAME (NG-nitro-L-arginine methyl ester) or the phosphodiesterase type 5 inhibitor sildenafil in response to PNS at submaximal frequency. Changes in blood flow were evaluated by comparing the area under the curve of each response. RESULTS: Reproducible frequency dependent increases in vaginal blood flow were observed in response to PNS. Administration of L-NAME (a NO synthase inhibitor) resulted in significant attenuation (25.6% to 18.2% vs control at 30 minutes, p <0.00001) of the PNS induced increase in vaginal blood flow. In contrast, sildenafil administration significantly increased PNS induced vaginal blood flow (166.9% +/- 25.8% vs control at 30 minutes, p <0.00001). CONCLUSIONS: Our data suggest that the rat is a useful and reliable animal model for investigating the vaginal arousal response. In addition, we used this model to demonstrate the important role of the NO-cyclic guanosine monophosphate pathway in vaginal arousal.

Animals↗
PubMed2004

Modulation of rat vaginal blood flow and estrogen receptor by estradiol.

PURPOSE: The effects of subphysiological and physiological levels of estradiol on vaginal blood flow and estrogen receptor were investigated. MATERIALS AND METHODS: Intact or ovariectomized female Sprague-Dawley rats were used. Two weeks after surgery rats were infused with vehicle (polyethyleneglycol), or estradiol at subphysiological (5 microg daily) or physiological (15 microg daily) concentrations for 14 days using osmotic pumps. Changes in vaginal blood flow elicited by pelvic nerve stimulation were assessed by laser Doppler flowmetry. Total levels of functional estrogen receptor were determined by radioligand binding and Western blot analyses were used to assess estrogen receptor (ER) alpha protein. RESULTS: Mean plasma estradiol concentration +/- SEM decreased by 63% in the vehicle group (intact 36.5 +/- 10.3 pg/ml). The subphysiological and physiological estradiol groups had plasma levels that were 55% and 83% of the intact group, respectively. Uterine and vaginal wet weight, and vaginal blood flow were significantly decreased in the vehicle group and normalized by physiological levels of estradiol. However, vaginal blood flow was significantly greater in the subphysiological estradiol group compared to intact animals. Specific binding of [H]estradiol in vaginal tissue extracts from intact rats was 0.51 fmol/mg protein and it was increased 30-fold in the vehicle group. ER binding in vaginal tissue in the physiological estradiol group decreased to levels that were comparable to those in intact animals, whereas estrogen receptor binding remained elevated in the subphysiological estradiol group. These changes were paralleled by ERalpha protein levels. CONCLUSIONS: Estradiol is crucial for maintaining optimal vaginal blood flow in the rat. Lower levels of plasma estradiol trigger compensatory ERalpha up-regulation.

Animals↗
PubMed2004

Physiology of female sexual function: animal models.

INTRODUCTION: Data concerning the physiology of desire, arousal, and orgasm in women are limited because of ethical constraints. Aim. To gain knowledge of physiology of female sexual function through animal models. METHODS: To provide state-of-the-art knowledge concerning female sexual function in animal models, representing the opinions of seven experts from five countries developed in a consensus process over a 2-year period. MAIN OUTCOME MEASURE: Expert opinion was based on the grading of evidence-based medical literature, widespread internal committee discussion, public presentation, and debate. RESULTS: Sexual desire may be considered as the presence of desire for, and fantasy about, sexual activity. Desire in animals can be inferred from certain appetitive behaviors that occur during copulation and from certain unconditioned copulatory measures. Proceptive behaviors are dependent in part on estrogen, progesterone, and drugs that bind to D1 dopamine receptors, adrenergic receptors, oxytocin receptors, opioid receptors, or gamma-amino butyric acid receptors. Peripheral arousal states are dependent on regulation of genital smooth muscle tone. Multiple neurotransmitters/mediators are involved including adrenergic, and nonadrenergic, noncholinergic agents such as vasoactive intestinal polypeptide, nitric oxide, neuropeptide Y, calcitonin gene-related peptide, and substance P. Sex steroid hormones, estrogens and androgens, are critical for structure and function of genital tissues including modulation of genital blood flow, lubrication, neurotransmitter function, smooth muscle contractility, mucification, and sex steroid receptor expression in genital tissues. Orgasm may be investigated by urethrogenital (UG) reflex, in which genital stimulation results in rhythmic contractions of striated perineal muscles and contractions of vagina, anus, and uterine smooth muscle. The UG reflex is generated by a multisegmental spinal pattern generator involving the coordination of sympathetic, parasympathetic, and somatic efferents innervating the genital organs. Serotonin and dopamine may modulate UG reflex activity. CONCLUSIONS: More research is needed in animal models in the physiology of female sexual function.

Anal Canal↗
PubMed2004

Summary of the recommendations on sexual dysfunctions in women.

INTRODUCTION: Women's sexual dysfunctions include persistent or recurrent disorders of sexual interest/desire, disorders of subjective and genital arousal, orgasm disorder, pain and difficulty with attempted or completed intercourse. There are limited recommendation/guideline documents pertaining to the diagnosis and treatment of women's sexual dysfunctions. AIM: To provide recommendations/guidelines concerning state-of-the-art knowledge for the clinical management of women's sexual dysfunctions. METHODS: An International Consultation in collaboration with the major sexual medicine associations assembled over 200 multidisciplinary experts from 60 countries into 17 committees. Committee members established specific objectives and scopes for various sexual medicine topics. The recommendations concerning state-of-the-art knowledge in the respective sexual medicine topic represent the opinion of experts from five continents developed in a process over a 2-year period. Ten experts from four countries compiled the Recommendations on Sexual Dysfunctions in Women. MAIN OUTCOME MEASURE: Expert opinion was based on grading of evidence-based medical literature, widespread internal committee discussion, public presentation and debate. RESULTS: Recommendations and guidelines concerning the various sexual dysfunctions were updated. A comprehensive assessment of medical, sexual and psychosocial history is recommended for diagnosis and management planning. Indications for general and focused pelvic genital examination and laboratory testing are included. Recently revised definitions for sexual desire/interest disorder, arousal disorders (genital, subjective, combined and persistent), orgasm disorder, dyspareunia and vaginismus are presented. An evidence-based approach to management is provided. CONCLUSIONS: There is a need for more research and scientific reporting, re-assessment, and management of women's sexual dysfunction including long-term outcome studies.

Algorithms↗
PubMed2003

Selective P2Y2 receptor agonists stimulate vaginal moisture in ovariectomized rabbits.

OBJECTIVE: To determine the expression of P2Y(2) receptors in vaginal and cervical tissues and the effects of P2Y(2) receptor agonists INS45973 and INS365 on vaginal moisture. DESIGN: Pilot in vivo and histological study using animal subjects. SETTING: Experimental laboratory research. ANIMAL(S): Female New Zealand White rabbits were used for in vivo studies and female cynomolgus monkey (Macaca fascicularis) was used for in situ hybridization. INTERVENTION(S): Rabbits were kept intact or ovariectomized. Two weeks after ovariectomy, animals received daily vaginal instillation of vehicle or drugs for 16 days. MAIN OUTCOME MEASURE(S): Vaginal moisture was assessed in rabbits on 4 separate days during the treatment period. The P2Y(2) receptor mRNA distribution was assessed by in situ hybridization of monkey vagina and cervix. RESULT(S): Compared to control, vaginal moisture was significantly diminished in ovariectomized animals treated with vehicle. INS365 (8.1%) and INS45973 (0.9%) increased vaginal moisture in ovariectomized animals to levels that were comparable to or significantly higher than control animals, respectively. In situ hybridization studies indicated that P2Y(2) receptor mRNA was localized to endocervical and cervical gland, epithelium, and stratified squamous epithelium of the vagina. CONCLUSION(S): INS45973 and INS365 may interact with P2Y(2) receptors in the cervix and vagina to stimulate vaginal moisture in the estrogen (E)-deprived state. The P2Y(2) receptor agonists provide a potential nonhormonal alternative for treating vaginal dryness in postmenopausal women.

Animals↗
PubMed2003

Cocaine and ephedrine-induced priapism: case reports and investigation of potential adrenergic mechanisms.

OBJECTIVES: To investigate the direct effect of ephedrine and cocaine on neurogenic contraction of penile trabecular smooth muscle. We also provide three case reports of patients who developed priapism secondary to using either cocaine or nonprescription weight loss formulations containing ephedrine. The use/abuse of cocaine has been associated with priapism. In addition, anecdotal evidence suggests that priapism may result from ephedrine use. However, the effects of cocaine and ephedrine on adrenergic regulation of cavernosal tissue and the potential role of sympathetic dysregulation in the development of priapism have not been studied. METHODS: Isolated rabbit penile cavernosal tissue strips in organ bath preparations were subjected to electrical field stimulation (EFS) at varying frequencies (5 to 40 Hz) in the absence or presence of ephedrine (60 microg/mL) or cocaine (10 microM). Tissues were then subjected to EFS every 30 minutes for up to 20 hours. RESULTS: Ephedrine and cocaine initially caused contractions in cavernosal tissue strips that persisted for several hours. EFS-induced contractions became attenuated over time in tissues treated with ephedrine or cocaine. Eventually, the contractile responses to EFS were not distinguishable from the basal tone, although the tissues remained responsive to exogenous phenylephrine. CONCLUSIONS: Functional activation of alpha-adrenergic receptors on trabecular smooth muscle does not appear to be impaired with prolonged cocaine or ephedrine exposure. However, chronic use of cocaine or ephedrine may deplete norepinephrine from sympathetic nerve terminals, leading to priapism.

Adrenergic alpha-Agonists↗
PubMed2003

Reperfusion of ischemic corporal tissue: physiologic and biochemical changes in an animal model of ischemic priapism.

OBJECTIVES: To assess the physiologic and biochemical changes resulting from ischemia and reperfusion. Effective therapy for ischemic priapism reestablishes corporal venous outflow and arterial inflow and results in increased corporal partial pressure of oxygen. Data are limited concerning reperfusion injury of ischemic erectile tissue associated with reactive oxygen species (ROS) and the potential role of ROS scavengers in the clinical therapy of ischemic priapism. METHODS: Anesthetized adult New Zealand white male rabbits (n = 7) were exposed to a low oxygen tension breathing gas to achieve hypoxia within the corpora cavernosa. This resulted in a mean systemic oxygen saturation of 60%. The pelvic nerve was electrically stimulated to induce penile erection, and the base of the erect penis was clamped. After varying durations of ischemia, the clamp was removed to allow reperfusion. We determined the intracavernosal oxygen tension, histologic changes, myeloperoxidase activity, and lipid peroxidation. RESULTS: Corporal partial pressure of oxygen progressively decreased as the duration of priapism increased. A statistically significant increase was noted in myeloperoxidase activity and lipid peroxidation with corporal reperfusion. Polymorphonuclear leukocyte infiltration was documented in the ischemic reperfused tissue. CONCLUSIONS: In the management of ischemic priapism, reperfusion causes erectile tissue injury owing to the presence of ROS. There is a need to investigate the utility of ROS scavengers and antioxidants in the management of ischemic priapism.

Animals↗
PubMed2003

Effects of ovariectomy and estrogen replacement on basal and pelvic nerve stimulated vaginal lubrication in an animal model.

The goal of this study was to investigate the effects of ovariectomy and estrogen replacement on vaginal tissue integrity and vaginal lubrication in basal conditions and in response to pelvic nerve stimulation (PNS). Two weeks after ovariectomy, female New Zealand White rabbits were administered vehicle or estradiol (200 micrograms/day) for an additional 2 weeks. Ovariectomy caused significant vaginal atrophy and diminished vaginal lubrication in the basal state and after PNS, compared to intact controls. Estrogen replacement normalized lubrication values and tissue wet weight to control levels. In conclusion, vaginal tissue integrity and lubrication are diminished by ovariectomy and are normalized by estrogen replacement.

Animals↗
PubMed2003

A prospective duplex Doppler ultrasonographic study in women with sexual arousal disorder to objectively assess genital engorgement induced by EROS therapy.

The EROS therapy device is FDA-approved for the treatment of women with sexual dysfunction and has been shown to improve sexual function and satisfaction. The aim of this study was to obtain objective information regarding the ability of the EROS Therapy device to induce clitoral and corpus spongiosum volumetric and hemodynamic changes following therapeutic use in women with sexual arousal disorder. Seven patients with sexual arousal disorder formed the study population. All seven subjects met inclusion and exclusion criteria, including having normal hormonal values at the time of the study. All seven subjects were able to comfortably operate the device. All seven reported either slight-to-moderate pleasure or orgasm at home with the device. We observed no adverse events. This study shows that EROS therapy is associated with significant increases in clitoral and corpus spongiosum diameter as well as with clitoral and corpus spongiosum peak systolic and end-diastolic velocity values.

Adult↗
PubMed2003

A review of the physiology and pharmacology of peripheral (vaginal and clitoral) female genital arousal in the animal model.

PURPOSE: We review contemporary scientific data concerning the physiology and pharmacology of peripheral female genital arousal responses in the animal (rabbit and rat) model. MATERIALS AND METHODS: We reviewed the contemporary literature and our research studies concerning physiology and pharmacology of peripheral genital arousal from 3 experimental animal models, including genital smooth muscle cell culture, genital strip organ bath and in vivo animal model studies. RESULTS: Nitric oxide (NO) appears to be a key pathway mediating clitoral smooth muscle relaxation. In the vagina NO appeared to have a more controversial role in mediating vaginal muscularis smooth muscle relaxation. Vasoactive intestinal polypeptide induced vaginal smooth muscle relaxation. Functional alpha-adrenergic receptors were expressed in the clitoris and vagina, and mediated norepinephrine induced genital smooth muscle contraction. Androgens and estrogens modulated distinct physiological responses in vagina, and androgens facilitated vaginal smooth muscle relaxation. Papaverine hydrochloride, a smooth muscle relaxant, and phentolamine mesylate, an alpha-blocker, administered into the vaginal spongy muscularis layer increased vaginal wall pressure and vaginal blood flow. Sildenafil caused significant increases in genital (clitoral and vaginal) blood flow and vaginal lubrication in intact and ovariectomized animals. This response was more pronounced in animals treated with estradiol, suggesting that the NO cyclic guanosine monophosphate pathway is involved in the physiological mechanism of female genital arousal and that sildenafil facilitates this response in an in vivo animal model. CONCLUSIONS: To achieve improved understanding of the biological aspects of female sexual function, further research is needed in the physiology and pharmacology of peripheral (clitoral and vaginal) genital arousal in the animal model.

Animals↗
PubMed2003

Vardenafil, a new phosphodiesterase type 5 inhibitor, in the treatment of erectile dysfunction in men with diabetes: a multicenter double-blind placebo-controlled fixed-dose study.

OBJECTIVE: This study evaluated the efficacy and safety of vardenafil treatment for erectile dysfunction (ED) in men with diabetes. RESEARCH DESIGN AND METHODS: In this prospective multicenter double-blind placebo-controlled fixed-dose parallel-group phase III trial, 452 patients with diabetes (type 1 or type 2) and ED were randomized to take 10 or 20 mg vardenafil or placebo as needed for 12 weeks. Efficacy responses were assessed by International Index of Erectile Function domain scores, rates of vaginal penetration and successful intercourse, and a global assessment question (GAQ) about erection improvement during the previous 4 weeks. RESULTS: After 12 weeks of treatment, a dose-dependent (P = 0.02) improvement in erections was noted for the GAQ, with 57 and 72% of men taking 10 mg or 20 mg vardenafil, respectively, reporting improved erections, in contrast to 13% after taking placebo (P < 0.0001). For the erectile function domain, dose-dependent (P = 0.03) final scores for the 10- and 20-mg dose were 17.1 and 19.0 compared with 12.6 for placebo (P < 0.0001). Both vardenafil doses significantly enhanced the rates of successful penetration (P < 0.0001) and successful intercourse (P < 0.0001) compared with placebo. Vardenafil treatment was effective in increasing intercourse success rates at all levels of baseline ED severity, at each level of plasma HbA(1c), and for type 1 and 2 diabetes. Treatment-emergent adverse events were primarily mild to moderate headache (<or=13%), flushing (<or=10%), and rhinitis (<or=10%). CONCLUSIONS: Vardenafil statistically improved erectile function and was generally well tolerated in these diabetic patients with ED.

Administration, Oral↗