Erection Responses Research Articles

(304) THE OVER/UNDER OF PEYRONIE’S DISEASE

Abstract Introduction Over/Under is a sportsbook wager term. Peyronie’s disease (PD) affects men of all ages with an estimated prevalence of up to 9% of the population. The Peyronie’s Disease Questionnaire (PDQ) Scale provides an opportunity to assess patient perception of their disease and the impact it has on quality of life. A potential discrepancy between patient-perceived and physician-measured curvature is important aspect of triaging care for patients with PD. Counseling, management and treatment risks are impacted by PD triage. Objective To investigate patient accuracy in perceived degree of curvature in Peyronie’s disease. Are patients over estimating or underestimating PD curvature? Methods A retrospective chart review was performed on 57 patients with diagnosis of Peyronie’s disease at our institution. Patients in the study completed a Peyronie’s Disease Questionnaire (PDQ) Scale with additional prompts including, but not limited to, penile curvature with erection, number of penile curvatures, and degree of each penile curvature. All patients had office based testing with intracavernous injection of Alprostadil and color duplex Doppler assessment (CDDU). The primary outcome was estimation of concordance of curvature estimated by patient and measured by provider. Patient overestimation was defined as perceived curvature more than 15 degrees greater than measured curvature. Underestimation was defined as patient-estimated curvature 15 degrees less than measured curvature. Results Of the 57 patients, 51 patients met study criteria with a completed questionnaire, documented physician-measured curvature, and absence of an hourglass deformity on examination. Patient concordance with physician-measure curvature within 15 degrees was observed in forty patients (78%). Overestimation of curvature was recorded in eight patients (16%), while three patients (6%) underestimated their curvature. Conclusions The PDQ Scale is a useful tool in assessing degree of curvature in patients with PD. We carefully selected men who had normal vascular erection responses to Alprostadil in office and compared provider measurements to patient’s home estimate of curvature. Our study finds that in men with no co-existing erectile dysfunction and no hourglass deformities the majority (78%) accurately estimate their penile curvature within 15 degrees of measured curvature. PDQ cannot replace physical examination of Peyronie’s disease or office based intracavernous induced erections as discordance between percieved and measured curvature is 22%. Disclosure No.

Oxytocinergic neurons, but not oxytocin, are crucial for male penile erection

The cumulative evidence suggests that oxytocin is involved in the male sexual behaviors. However, no significant sexual impairments were observed in oxytocin gene knock-out (KO) mice, suggesting that oxytocin is not necessary for sexual behavior in male mice. To better understand the role of oxytocin in male erection, two types of oxytocin gene KO mice were created. In the first type, the oxytocin gene was deleted in the zygote, while in the second type, the oxytocin gene was mutated in adulthood by injecting the CRISPR/Cas9 AAVs. The results showed that disrupting the oxytocin gene at either the embryonic or adult stage did not affect erection, indicating that oxytocin is not necessary for penile erection. Pharmacologically, injecting oxytocin receptor agonist Carbetocin into the VTA of the oxytocin gene KO mice still evoked penile erection. By employing the Oxt-Ires-Cre mice, we found that specifically activating oxytocinergic neurons through chemogenetics strongly induced penile erection, while inhibiting these neurons blocked the erection responses. Furthermore, ablating PVN oxytocinergic neurons abolished the male erection response. In conclusion, although the neuropeptide oxytocin is not essential for male erection, the activity of oxytocinergic neurons is required. Our results might reflect the redundancy in the central nerve system in the sense that many signals contribute to the activation of oxytocinergic neurons to evoke penile erection during sexual behaviors.

Penile erection responses of Nigella sativa seed extract on isolated rat corpus cavernosum

Nigella sativa L. (NS) from Ranunculaceae family is known as black cumin in Indonesia. The seed has been used as an aphrodisiac in ethnobotanical studies and reported to have pharmacological activities such as antihypertensive through the relaxant effect of vascular smooth muscles but the direct effect to the blood vessels of the corpus cavernosum is still unknown. The purpose of this study was to examine the response of NS seed extract on penile erection in vitro. NS seeds were macerated in ethanol solvent for three days in room temperature and repeated for two times. Penile erection responses was assessed using isolated rat corpus cavernosum in Krebs-Henseleit solution, temperature 37°C, pH 7.4, aerated with carbogen gas. After acclimation, corpus cavernosum was contracted with a phenylephrine solution. Ethanolic extract of NS seeds or control solution were given after reaching the plateu phase of the highest contraction. This study showed that the contraction response of the corpus cavernosum decreased after addition of NS extract and this action was increased with the addition of the extract concentration. This study concluded that NS seed ethanol extract affects the penile erection response directly through the relaxation of blood vessels in the corpus cavernosum.

Pharmacotherapy for Erectile Dysfunction

Advances in understanding of the biochemistry and physiology of penile erection have led to breakthroughs in pharmacotherapy of erectile dysfunction. To provide recommendations/guidelines concerning state-of-the-art knowledge for the putative molecular and cellular mechanisms of action of centrally and peripherally acting drugs currently utilized in pharmacotherapy of erectile dysfunction. An international consultation in collaboration with the major urology and sexual medicine associations assembled over 200 multidisciplinary experts from 60 countries into 17 committees. Committee members established specific objectives and scopes for various male and female 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 two-year period. Concerning the Pharmacotherapy for Erectile Dysfunction Committee there were 25 experts from 10 countries. Expert opinion was based on grading of evidence-based medical literature, widespread internal committee discussion, public presentation and debate. Selective and potent oral PDE5 inhibitors have significantly more affinity than cGMP and form broader molecular interactions with multiple amino acids, thereby blocking access to cGMP in the catalytic sites of the PDE5 enzyme. PDE5 inhibitors, which vary as to biochemical potency, selectivity and pharmacokinetics, lead to cGMP elevation and relaxation facilitation of penile corpus cavernosum smooth muscle cells following sexual stimulation. Various centrally acting drugs influence sexual behaviour. In particular, the dopaminergic substance apomorphine is a central enhancer that acts in the paraventricular nucleus of the hypothalamus as a dopamine (D2) receptor agonist, induces and increases penile erection responses via disinhibition, following sexual stimulation. There is a need for more research in the pharmacotherapeutic development of central and peripheral agents for safe and effective erectile dysfunction treatment.

A new potential of blood oxygenation level dependent (BOLD) functional MRI for evaluating cerebral centers of penile erection.

It is well known that penile erection is dependent on commands from the central nervous system. However, there has been little research on the central control of penile erection. The aim of this study was to evaluate, for the first time, the cerebral centers of penile erection using BOLD-functional MRI. Functional magnetic resonance imaging (fMRI) on a 1.5T MR scanner was performed in 12 sexually potent male volunteers (mean age: 23) and two hypogonadal impotent patients. In this study, blood oxygenation level dependent (BOLD) technique was utilized to create fMRI reflecting local brain activities. Real-time visual stimulation was performed with an alternatively combined erotic and non-erotic film to identify and quantify the activated brain regions associated with sexual response. Subjective sexual arousal and penile erection responses were assessed using 5-point scales ranging from 1 (no change) to 5 (maximal increase). In normal volunteers, the mean scores on subjective sexual arousal and penile erection by sexual stimulation with erotic film were 3.0 and 3.3 respectively, whereas there were no changes by non-erotic stimulation. During the visual stimulation the occipital cortex was activated by either an erotic or non-erotic film, the erotic film gave 150-200% stronger activation. However, more than seven of the 12 healthy subjects were significantly activated in the areas of inferior frontal lobe, cingulate gyrus, insula gyrus, corpus callosum, thalamus, caudate nucleus, globus pallidus, and inferior temporal lobe by erotic stimulation. In the hypogonadal patients, brain activation in response to the erotic film decreased compared to normal volunteers, however, it was restored by testosterone supplementation. These results are the first demonstration to show the functional neuroanatomy of the brain associated with sexual arousal by visual sexual stimulation using BOLD-based fMRI. Further studies are needed to verify that fMRI provides an important new tool in evaluating the cerebral center of the penile erection.

Paraventricular nucleus controls 5-HT 2C receptor-mediated corticosterone and prolactin but not oxytocin and penile erection responses

There is evidence that administration of the 5-HT 2C receptor agonist, m-chlorophenylpiperazine (m-CPP), increases plasma concentrations of oxytocin, prolactin, corticosterone, induces penile erections and excessive grooming in male rats. To test the hypothesis that the hypothalamic paraventricular nucleus mediates these neuroendocrine and behavioural responses, we measured the effects of m-CPP (0.6 mg/kg i.v.) on these parameters in chronically cannulated, freely moving male rats after surgical lesion of the paraventricular nucleus or sham operation. Paraventricular nucleus lesion markedly attenuated prolactin, corticosterone and excessive grooming, but not oxytocin and penile erection responses to m-CPP. In contrast, both oxytocin and corticosterone responses to the dopamine receptor agonist, apomorphine (0.05 mg/kg i.v.), were attenuated in lesioned rats. The present studies suggest that the paraventricular nucleus mediates m-CPP-induced prolactin, corticosterone and probably also excessive grooming responses, and the mechanisms of apomorphine and m-CPP action on oxytocin secretion and penile erection responses differ.

A comparison of Nocturnal Penile Tumescence and penile response to erotic stimulation during waking states in comprehensively diagnosed groups of males experiencing erectile difficulties

The erectile responses of 13 nondysfunctional males and 48 dysfunctional males were compared during Nocturnal Penile Tumescence (NPT) and during exposure to erotic videotapes. The results showed distinct patterns of NPT and daytime responding that could differentiate the various subgroups: those displaying (i) no dysfunction; (ii) vasculogenic erectile dysfunction; (iii) high risk for erectile dysfunction (organic and psychogenic); (iv) psychogenic dysfunction; reactive to erotica; and (v) psychogenic dysfunction; nonreactive to erotica. Subjects participating in this study underwent a comprehensive medical and psychological screening to place them in each subgroup. The penile circumference response to erotic stimuli used in conjunction with NPT response appeared useful in differentiating subgroups of erectile dysfunction and suggested the need for further diagnostic refinement in this area. The majority of vasculogenic dysfunctional subjects experienced greater erection responses during exposure to erotic stimulation than during NPT; several of these subjects achieved almost full erections in waking states but were practically flaccid at night. The discussion covers diagnostic and therapeutic implications.

Differential sexual responding among four groups of sexual offenders against children

Previous literature on typologies of child molesters has separated groups into those that display a primary sexual orientation to children (the pedophile) versus those where children serve as a surrogate (i.e., the incest case). However, empirical evidence to substantiate this distinction has been conflicting. A study by Quinsey et al. (1979), employing physiological measures of erection responses to slide stimuli, supported the above distinction. However, Abel et al. (1981), measuring erection responses to audiotaped descriptions of sexual interactions with children, found no differences between pedophiles and incest cases. The present study compared erection responses to slide and audiotaped stimuli of four groups of offenders against children: homosexual pedophiles, heterosexual pedophiles, incest cases, and a mixed diagnostic group. In general, regardless of the scoring method employed (percentage full erection or z-score transformation), the results indicated that with slide stimuli, pedophiles showed more responding to children than adults, while the opposite was true for the incest cases. However, with audiotaped descriptions, all groups evidenced more responding to children than adults. Reasons for the differences observed with various types of stimulus material are discussed, as are treatment implications.

Differential erection response patterns of sexual child abusers to stimuli describing activities with children

The plethysmographic measurement of erection responses to auiiotape descriptions of different types of sexual and aggressive activities with children was extended to a much larger sample of sexual child abusers than previously in vestigated in order to assess the usefulness of this evaluation procedure for differentiating between the most dangerous, physically harmful offenders and the more harmless, nonaggressive abusers. The study involved the assessment of 16 less dangerous and 15 more dangerous sexual offenders against children in response to audiotape descriptions of pregenital consenting fondling, consenting intercourse, physically pressured nonconsenting intercourse, aggressive intercourse, and purely physical assault with children. Results indicated that the more violent offenders responded significantly more to the aggressive cues than did the less dangerous abusers. Subjects' limited ability to suppress undesired deviant arousal did not substantially alter the data. There was a significant difference in the arousal levels achieved between 2 and 4 min of stimulus presentations, suggesting the need for longer than the 2 min of stimulus exposure usually afforded in physiological measurement studies of sexual offenders. Results of the study suggest the advantages of this classification procedure over more traditional, static and less objective methods but also indicate the great need for further research to establish the procedure's predictive validity and reliability.

Effect of telencephalon ablation on the reinforcing and eliciting properties of species-specific events in Betta splendens.

In male Betta splendens, aggressive behavior is drastically attenuated following telencephalon ablation. Because instrumental training and Pavlovian conditioning experiments with intact fish have suggested that associative factors may play an important role in the performance of agonistic behaviors, the effect of ablation on instrumental learning and Pavlovian conditioning was studied. In Experiment 1, ablation had no effect on the learning of the instrumental tunnel-swimming response reinforced by mirror presentation (i.e., viewing a conspecific), although the mirror presentations in yoked-control groups elicited fewer responses in ablates than in normal and sham-operated control fish. Yoked controls further established that instrumental responding was maintained by the reinforcement contingency and was not merely the result of increased motor activity. Experiment 2 studied Pavlovian conditioning of the components of the agonistic display. Unconditioned fin erection, gill erection, and tail beating (i.e., unconditioned responses, URs) to the mirror US all were less frequent in ablates than in normals or shams. Of these, only gill cover erection showed evidence of true conditioning (i.e., conditioned responses; CRs) in which responses to the conditioned stimulus (CS) are due to the pairings of CS and US (unconditioned stimulus). However, ablates suffered no impairment of conditioned gill erections. Ablates performed fewer fin erections to the CS; however, fin erection responses were not due to CS-US pairings but were attributable to pseudoconditioning. These results are related to hypotheses postulating the involvement of learning mechanisms in ablation-produced deficits and normal aggressive behavior.

Feasibility of Controlled Micturition through Electric Stimulation

Historically, man has been aware of bioelectric phenomena for some 4,000 years. Yet it has only been during the last 20 years that technology has advanced to the stage where controlled bladder emptying has become feasible. A great deal of interest followed the introduction of transistor and bladder stimulation via the principle of radio frequency induction. Spinal cord, sacral, and pelvic nerve and direct bladder stimulation have all been attempted. Only direct bladder stimulation in lower motor neuron situations has shown any promise. The many difficulties associated with bladder stimulation include simultaneous sphincter contraction, pain, electrode and insulation difficulties, and fibroplasia due to movement of electrodes placed in pliable tissues. In addition, the role of the prostate, increased urethral length, and erection responses in the male have received little investigation. These problems are outlined and experimental observations of attempts to achieve controlled micturition in canines areresented. These studies were carried out over a 3-year period, and emphasize responses to stimulation of the spinal cord and sacral roots. It was concluded that the most efficient manner by which to effect simulated micturition is via stimulation of the ventral sacral root dominant for bladder responsiveness, and combine this with selective division of somatic fibers of only the root being stimulated.

Penile Responses To Visual Stimuli

As a greater number of treatment units have investigated the use of the penile transducer to evaluate child molesters and rapists, greater interest has focused on the issues of the validity of these procedures. Of greatest concern is the extent to which clients might fake their erection responses so as to give false information regarding their arousal patterns or response to treatment. For this reason, two papers have been included that deal with specific issues regarding fakability. In attempting to understand this problem, the reader should not receive the impression that treatment centers rely exclusively on such psychophysiologic measurement techniques. These measures are but one means of evaluating the client's response to treatment and must be incorporated in the sum total of information used to evaluate the client's current status. Quinsey and Carrigan describe a study of nine nondeviates who were instructed to fake a deviant sexual preference during the measurement of their sexual arousal with the penile transducer. These data confirmed that normals can fake deviant arousal patterns either while simply looking at deviant slides or when looking at deviant slides while listening to audio descriptions of deviant sexual behavior with the individuals appearing in the slides. These results lend further support to the need for the cautious interpretation of penile measures in determining sexual preferences with aggressives.

Differentiating Sexual Aggressives With Penile Measures

Evaluating how a client is doing in therapy is a problem faced by all therapists. This is an especially important issue when the client is a rapist or child molester, since not knowing that his control is poor or that he has failed to respond to treatment may jeopardize the safety of others. Therapists have traditionally relied on the client's self-report to evaluate how he is doing. This traditional method of assessment in some cases is quite efficient and provides the therapist with extensive details that assist in outlining further treatment plans for the offender. In working with sexual deviates, however, it is quite apparent that in many cases this self-report is totally unreliable. As a consequence, the therapist must rely on other methods to assess his client's progress. For a number of years, penile transducer measures have been used to assess the sexual arousal of various sexual deviates. This is accomplished by the use of a small penile transducer which encircles the penis and records erection responses during the presentation of various sexual stimuli. In recent years, this method has been applied to the assessment of child molesters and sexual aggressives. Abel, Blanchard, Becker, and Djenderedjian summarize their recent work on the use of penile transducers with child molesters and rapists. The correlation of such measures with the sexual aggressive's history of sexual aggressive behavior, the frequency of that behavior, the likelihood of excessive force being used during the commission of a sexual assault, the likelihood of the client being a sadomasochist, and age of the aggressive's preferred victim is discussed. Preliminary data indicate that these physiologic measures have tremendous potential for assisting the therapist in assessing not only the treatment needs of the sexual aggressive, but also his response (or failure to respond) to treatment.

Sexual Response Faking By Pedophiles

Finally in this series, Laws and Holmen examine further the issue of response faking by looking at various methods used by one of their own clients as he attempted to fake in the laboratory. It is clear that clients have the capability of generating erection responses to stimuli that are not erotic to them and the ability to prevent their erection responses to sexual stimuli to which they normally are highly aroused to. Furthermore, therapists' maneuvers to prevent such faking may significantly disrupt the working relationship between the therapist and the client. Laws and Holmen conclude by listing various steps that the therapist can take so that faking by the client will be minimized. Clearly, no one has the answer for this most difficult scientific and ethical issue. Laws and Holmen's results simply highlight the problems in dealing with rapists and child molesters, problems that are present in treating other types of clients but whose solution becomes critical to protect potential victims of our clients.

Measurement of sexual arousal in male homosexuals: effects of instructions and stimulus modality.

Erections were measured in 20 male homosexual subjects under three instructional conditions and within three stimulus modalities. The three conditions were arousal (e.g., imagine yourself involved and get aroused), suppression (e.g., imagine yourself involved bu suppress erection responses), and rearousal (e.g., imagine yourself involved and get aroused). The three stimulus modalities studied were video tapes, slides or pictures, and audio tapes of homosexual cues. The results show that video tape generates the highest level of arousal, audio tape the lowest level of arousal, and slides an intermediate level. Both video tape and slides show substantial voluntary suppression effects. During suppression, video tape continues to elicit relatively high levels of arousal in contrast to slides and audio tapes, which are equally low.