Genital lubrication: A cue-specific sexual response?

Women's genital responses are sensitive to the presence and intensity of sexual cues, yet some stimulus features (e.g., male vs. female actors, consensual vs. non-consensual interactions) have little influence on the magnitude of response-a phenomenon called low cue-specificity. Genital responses are typically assessed using vaginal photoplethysmography, a measure of vaginal vasocongestion, itself a precursor to lubrication. One explanation for low cue-specificity is the preparation hypothesis: Women genitally respond to almost all sexual cues because lubrication functions to protect genital organs from potential injury should vaginal penetration occur. In order to test the preparation hypothesis, both vaginal vasocongestion and introital lubrication were assessed in a sample of 20 women in response to sexually explicit films. While patterns of vasocongestion were consistent with low cue-specificity for gender cues and type of sexual activity, lubrication was specific to women's most preferred sexual stimulus categories. These results are inconsistent with the preparation hypothesis.

Efficacy of red clover isoflavones in the menopausal rabbit model.

OBJECTIVE: To evaluate the effectiveness of phytoestrogens as alternatives for selective dysfunctional changes in the menopausal rabbit model. DESIGN: Prospective, vehicle-controlled experimental study. SETTING: Reproductive pharmacology laboratory in a university department. ANIMAL(S): Twenty-four rabbits with experimentally induced menopause and six intact controls. INTERVENTION(S): Surgical menopause was induced in 24 rabbits by ovariectomy. After 4 weeks of convalescence, three groups (n = 6) were given 100 microg/kg E(2) valerate, 100 microg/kg daidzein, or 6.68 mg/kg red clover extract daily for 12 weeks. The remaining six rabbits served as the operated control group. MAIN OUTCOME MEASURE(S): Vaginal blood flow using Doppler flowmetry, before, during, and after pelvic nerve stimulation; and measured parameters of uterine weight, femoral bone density, clitoral cavernosal histology, and hormone levels. RESULT(S): After pelvic nerve stimulation, blood flow increased remarkably in the daidzein-treated group. Serum E(2) and uterine weight increased significantly in the estrogen group. Cavernosal structure was well preserved in all three treatment groups, and bone mineral density was lowest in ovariectomized controls (0.3467 g/cm(2)) and highest in the red clover (0.4012 g/cm(2)) groups. CONCLUSION(S): Supplementing isoflavones for menopause leads to significant improvements in bone density, tissue integrity, and vaginal blood flow with minimal effect on uterine weight and may therefore be a viable alternative to conventional regimens using synthetic estrogens.

Short- and long-term effects of Ginkgo biloba extract on sexual dysfunction in women.

Ginkgo biloba extract (GBE) facilitates blood flow, influences nitric oxide systems, and has a relaxant effect on smooth muscle tissue. These processes are important to the sexual response in women and, hence, it is feasible that GBE may have a therapeutic effect. The present study was the first to provide an empirical examination of the effects of both short- and long-term GBE administration on subjective and physiological (vaginal photoplethysmography) measures of sexual function in women with Sexual Arousal Disorder. A single dose of 300 mg GBE had a small but significant facilitatory effect on physiological, but not subjective, sexual arousal compared to placebo in 99 sexually dysfunctional women. The long-term effects of GBE on sexual function were assessed in 68 sexually dysfunctional women who were randomly assigned to 8 weeks treatment of either (1) GBE (300 mg/daily), (2) placebo, (3) sex therapy which focused on training women to attend to genital sensations, or (4) sex therapy plus GBE. When combined with sex therapy, but not alone, long-term GBE treatment significantly increased sexual desire and contentment beyond placebo. Sex therapy alone significantly enhanced orgasm function compared with placebo. Long-term GBE administration did not significantly enhance arousal responses beyond placebo. It was concluded that (1) neither short- or long-term administration of GBE alone substantially impacts sexual function in women, (2) a substantial placebo effect on sexual function exists in women with sexual concerns, and (3) teaching women to focus on genital sensations during sex enhances certain aspects of women's sexual functioning.

The effects of false positive and false negative physiological feedback on sexual arousal: a comparison of women with or without sexual arousal disorder.

The effects of false positive and false negative physiological feedback (vaginal photoplethymograph response print-out) on women's sexual arousal were examined. Participants included women without sexual dysfunction (n=16) and women with Sexual Arousal Disorder (SAD; n=15). Measures of subjective sexual arousal, physiological sexual arousal (vaginal pulse amplitude), expectancies, affect, and anxiety were obtained in response to viewing an erotic film. Results indicated that false positive feedback significantly increased subjective levels of sexual arousal, whereas false negative feedback significantly decreased subjective levels of sexual arousal in both groups. Sexually functional women had overall higher expectancies for sexual arousal than women with SAD. Unexpectedly, false positive feedback did not significantly impact physiological sexual arousal in sexually functional women; however, it resulted in significantly decreased responses in physiological sexual arousal in women with SAD. False negative feedback had no significant effect on physiological sexual response in sexually functional women or women with SAD.

Possible improvement of the clitoral and vaginal blood flow using a somatostatin analog in chronic spinalized Sprague-Dawley rats.

We evaluated the effect of a somatostatin analog (octreotide) on clitoral and vaginal blood flow following suprasacral spinal cord injury (SCI) in rats. Twenty-four spinalized female Sprague-Dawley rats were randomized into 4 equal groups. The first group served as control paraplegics. The other three groups received octreotide (60 micrograms/day/4 weeks) immediately, 2 weeks, and 4 weeks following SCI. At the end of the experiment, a laser Dopper was used to measure blood flow changes following clitoral and pelvic nerve plexus stimulations. Marked decreases in both clitoral and vaginal blood flow in the control paraplegics were recorded. Significant increases (p < 0.05) in both clitoral and vaginal blood flow were recorded in animals that received octreotide; however, the increase was marked in the animals that received the drug immediately following SCI. Improvement in the clitoral and vaginal blood flow of spinalized rats using octreotide indicates that octreotide may be helpful for patients with SCI.

Neurophysiology and pharmacology of female genital sexual response.

Vaginal sexual arousal is a vasocongestive and neuromuscular event controlled by facilitatory parasympathetic and inhibitory sympathetic inputs. Autonomic preganglionic parasympathetic and inhibitory sympathetic fibers to the vagina and clitoris originate in the spinal cord in the sacral parasympathetic nucleus at the sacral level and in the dorsal gray commissure and the intermediolateral cell column at the thoracolumbar level, respectively. Parasympathetic fibers are conveyed by the pelvic nerve, and sympathetic fibers are conveyed by the hypogastric nerve and the paravertebral sympathetic chain. The activity of these spinal nuclei is controlled by descending projections from the brain and sensory afferens (conveyed in the pudendal, hypogastric, pelvic, and vagus nerves) from the genitalia. A key but unresolved issue concerns the neurotransmitters involved in the control of genital sexual arousal. At the peripheral level, acetylcholine plays a minor role in the regulation of vaginal blood flow, however, recent data suggests that it may be involved in the control of vaginal smooth muscle contractions. Vasoactive intestinal peptide and nitric oxide may be responsible for the increase in vaginal blood flow during sexual arousal, whereas noradrenaline is likely inhibitory. Within the central nervous system, serotoninergic projections from the brain to the spinal cord likely inhibit the induction of genital arousal by peripheral informations (spinal reflex). Although some neurotransmitters regulating the display of sexual behavior have been identified (for example, dopamine), their involvement in the control of genital sexual arousal has not been invested. Anatomical and electrophysiological data point to a contribution of the paraventricular nucleus of he hypothalamus and the median preoptic area, respectively, as key elements in the control of genital arousal. The recent development of models allowing the assessment of vaginal sexual arousal in anesthetized female rats should assist in deciphering the neurochemical pathways controlling vaginal sexual arousal and the development of suitable pharmacological treatment for female sexual dysfunctions.

Hemodynamic evaluation of the female sexual arousal response in an animal model.

The goal of this study was to assess the utility of existing and new techniques for characterizing and measuring hemodynamic changes in the vagina and clitoris in response to pelvic nerve stimulation (PNS) in an animal model. Using female New Zealand White rabbits, we measured the following parameters before, during, and after PNS at 4, 16, and 32 hertz (Hz): clitoral hemoglobin (Hb) content by laser oximetry, clitoral blood flow by laser Doppler flowmetry, vaginal luminal pressure of upper and lower segments, and clitoral intracavernosal pressure. Clitoral tissue concentrations of total and oxygenated hemoglobin (oxy-Hb) increased in a frequency-dependent manner while deoxygenated hemoglobin (deoxy-Hb) concentration decreased. The duration of the responses at 16 and 32 Hz were significantly greater than at 4 Hz. Clitoral blood flow increased significantly only at 32 Hz with a prolonged response duration, relative to 4 Hz. PNS caused vaginal luminal pressure changes that were highly variable, but qualitatively different, between the upper and lower regions. Clitoral intracavernosal pressure did not change significantly in response to PNS. Measurement of changes in tissue Hb content by the novel technique of laser oximetry provides a direct assessment of blood flow in a noninvasive manner and may prove to be a powerful tool in evaluating hemodynamic aspects of the female genital sexual response.

CT of abdominal barium intravasation.

We report a case of barium intravasation due to misplacement of the catheter tip during a barium enema examination, leading to vaginal laceration and barium sequestration within the reticuloendothelial system of a 57-year-old woman who survived this potentially fatal event. The radiologic appearance on CT, sonography, MR, and plain radiography is presented. Computed tomography demonstrated barium sequestered by the liver, spleen, and renal cortex. The portal veins were seen as branching radiolucent densities superimposed on a dense parenchymal background.

Hemodynamics of sequential orgasm.

Seventeen women masturbated to orgasm several times in succession while being measured intravaginally by a device that allows continuous oxygen and blood flow readings. Analysis of covariance showed significant differences between fantasy and orgasm and between orgasm and interorgasm relaxation periods. The data do not provide physiological evidence that successive orgasms are either physiologically or subjectively stronger but do provide physiological evidence of a plateau phase of sexual response in women.

Fatal barium embolization due to incorrect vaginal rather than colonic insertion. An ultrastructural and x-ray microanalysis study.

Fatal generalized barium sulfate (BaSO4) embolization followed erroneous vaginal insertion of the enema tip intended for colon examination. Light microscopy revealed the presence of swollen, granular reticuloendothelial cells in most visceral organs such as lung, liver, spleen, bone marrow, kidney, and brain. Transmission electron microscopy showed the reticuloendothelial cells loaded with uniformly electron-dense granules of various sizes. Scanning electron microscopy equipped with an energy-dispersive x-ray analyzer confirmed the BaSO4 composition of these granules when unstained paraffin sections of different organs mounted on glass slides without coverslips were examined. The use of the technique of x-ray microanalysis is recommended when absolute identification of inorganic material in human organs is needed. The technique can be used directly on routine paraffin-embedded material mounted on glass slides as well as with material expressly prepared.

Psychophysiological aspects of sexual dysfunction.

The argument is made that human sexual dysfunction is particularly well suited for investigation within the conceptual framework embraced by psychophysiology, due to the unique participation of both physiological and psychological components in the sexual response cycle. The literature relating psychophysiological research to the investigation of sexual dysfunction is reviewed, indicating promising applications in the diagnosis and treatment of some sexual dysfunctions as well as in the evaluation of sex therapy programs and the testing of medical theories about the etiology and maintenance of sexual dysfunctions.

Biofeedback-assisted sexual arousal in females: a comparison of visual and auditory modalities.

This study was undertaken to investigate the effects of instructional set and biofeedback modality upon the ability of 23 females to achieve control over sexual arousal. Two levels of instructional set (increase, decrease) were completely crossed with three feedback modalities (audio, visual, no feedback). Changes in vaginal blood volume (VBV) and vaginal pulse amplitude (VPA) were monitored by a vaginal plethysmograph and reduced on line by a microcomputer. During feedback trials, all subjects received audio- or visual feedback of the VBV response. Subjects participated in two sessions, each consisting of six 3-minute trials, one in each instruction/feedback combination. Order of trials was counterbalanced. Subjective levels of arousal, VBV, and VPA were significantly higher under increase instructions. Also, a significant feedback effect was noted in the subjective measure and the VBV measure, favoring visual feedback for overall control of sexual arousal. However, the feedback effect accounted for a small portion of the variance, and it was concluded that performance was not appreciably superior with or without feedback. Thus practical considerations may determine the feedback modality to be used for vaginal vasocongestion in future research. Higher positive correlations of subjective ratings with vaginal blood volume occurred during feedback trials, which suggests that biofeedback may be helpful in discrimination training to facilitate awareness of the feelings associated with different arousal levels and correct labeling of increased vasocongestion as sexual. Further research is necessary to see if sexually dysfunctional women can benefit from a biofeedback component in a comprehensive therapy program and to determine the effect of many training sessions on discrimination and self-control of arousal.

Discriminative control of the vaginal vasomotor response.

With use of a discriminative control procedure and operant techniques, women significantly increased their vaginal pulse amplitude (produced vaginal vasodilation) but did not significantly decrease vaginal pulse amplitude (produce vaginal vasoconstriction). Acquisition of vaginal pulse amplitude control was rapid with no significant improvement over trials or the 5 experimental days. Specificity of vaginal pulse amplitude control occurred in relation to the other vasomotor responses, including vaginal blood volume and digital pulse amplitude. Vagnial pulse amplitude changes were not related to somatic-muscular, respiratory, or heart-rate changes. Women who used oral contraceptives were better able to control vaginal pulse amplitude than women who used other forms of birth control. Although the sexual behavior of these two groups and did not differ, women in the latter group tended to be more clitorally oriented.

Genital blood flow measurement: feedback applications in sexual therapy.

Laboratory techniques are now available for measurement of both male and female genital engorgement during sexual arousal. When laboratory subjects are given information on their rate and amplitude of tumescence (biofeedback), they appear to acquire greater voluntary control of the response. Data from two experiments and a case study are presented to illustrate the application of biofeedback in both facilitation and suppression of penile responding. A PhD student is currently conducting analogous research with female subjects. Clinicians are cautioned against careless application of biofeedback techniques for the treatment of erectile inadequacies.