Control Of Sexual Arousal Research Articles

Experimental Evidence for Sildenafil's Action in the Central Nervous System: Dopamine and Serotonin Changes in the Medial Preoptic Area and Nucleus Accumbens During Sexual Arousal

Sildenafil is the first effective oral treatment for male erectile dysfunction. Although it is generally accepted that its action is peripheral, it has been suggested that it influences central neural pathways that are involved in male sexual arousal. Recently, it was shown that local sildenafil administration enhances extracellular dopamine (DA) in the nucleus accumbens (NAcc). The aim of this study was to determine whether sildenafil administration alters dopaminergic and serotonergic activity in the NAcc and the medial preoptic area (mPOA) during a model of sexual arousal. An acute (2 days) or chronic (21 days) sildenafil regimen (1 mg/kg) was administered intraperitoneally to male rats. Thirty minutes after the last sildenafil injection, all males were exposed to noncontact erection sessions by the presentation of inaccessible estrous females. Half of the males had previous experience of noncontact sexual encounter and the other half were exposed for the first time. Tissue levels of DA and its metabolites, 3,4-Dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), as well as serotonin (5-HT) and its metabolite 5-HIAA, were measured in the mPOA and NAcc with high-performance liquid chromatography with electrochemical detector. Dopamine ([DOPAC+HVA]/DA) and serotonin (5-HIAA/5-HT) turnovers were also calculated as indices of neurotransmission. In nontrained males, acute and chronic sildenafil treatment increased DA and 5-HT turnover rates in the mPOA and NAcc. In trained rats, acute sildenafil also increased DA and 5-HT turnover rates in both structures, whereas chronic treatment enhanced 5-HT turnover rate only in the mPOA and DA turnover rate only in the NAcc. Our data confirm that sildenafil enhances dopaminergic activity in the NAcc, extend these findings to the mPOA and furthermore, reveal sildenafil-induced effects on serotonergic activity in these brain regions as well. Therefore, present findings support an effect of sildenafil on central neural pathways that are involved in the control of sexual arousal.

Cognitive-Behavioral Treatment of an Adolescent Sexual Offender With an Intellectual Disability

Very little data exist on the treatment of adolescent sexual offenders with an intellectual disability despite evidence suggesting that intellectual deficits play a significant role in sexual offending. This case study describes use of cognitive-behavior therapy with an adolescent sexual offender diagnosed with an intellectual disability. Sexual offenders with an intellectual disability often present with certain skill deficits that require an adaptation of traditional treatments. This case study used a novel application of exposure and response prevention for the purpose of building skills that allow for effective control of sexual arousal and sexually offensive behavior. Results of this case study suggest that exposure and response prevention, as part of traditional cognitive-behavioral therapy, may be a useful treatment strategy for adolescent sexual offenders with a noted intellectual disability. Implications of the case are discussed and recommendations to clinicians working with this population are made.

Is there an inhibitory role of cortisol in the mechanism of male sexual arousal and penile erection?

It has been speculated for more than 2 decades whether there is a significance of adrenal corticosteroids, such as cortisol, in the process of normal male sexual function, especially in the control of sexual arousal and the penile erectile tissue. However, only few in vivo studies have been carried out up until now on the effects of cortisol on human male sexual performance and penile erection. In order to evaluate further the role of cortisol in male sexual activity, the present study was conducted to detect serum levels of cortisol in the systemic and cavernous blood taken during different penile conditions from healthy males. The effects of cortisol derivative prednisolone, catecholamine norepinephrine (NE) and the peptide endothelin-1 (ET-1) on isolated human corpus cavernosum (HCC) were investigated using the organ bath technique. Fifty-four healthy adult male subjects were exposed to erotic stimuli in order to elicit penile tumescence and rigidity. Whole blood was simultaneously aspirated from the corpus cavernosum and the cubital vein during different penile conditions. Serum levels of cortisol (microg/dl) were determined by means of a radioimmunoassay (ELISA). In the healthy volunteers, cortisol serum levels significantly decreased in the systemic circulation and the cavernous blood with increasing sexual arousal, when the flaccid penis became rigid. During detumescence, the mean cortisol level remained unaltered in the systemic circulation, whereas in the cavernous compartment, it was found to decrease further. Under all penile conditions, no significant differences were registered between cortisol levels in the systemic circulation and in the cavernous blood. Cumulative addition of NE and ET-1 (0.001-10 microM) induced contraction of isolated HCC strips, whereas the contractile response to prednisolone was negligible. Our results strongly suggest an inhibitory role for cortisol in the mechanism of male sexual response and behaviour. These properties are mediated rather via an effect on central structures than on the penile erectile tissue. Future studies to include patients suffering from erectile dysfunction may reveal whether or not there are differences in the cortisol serum profiles of healthy subjects and patients under different stages of sexual arousal.

Oxytocin plasma levels in the systemic and cavernous blood of healthy males during different penile conditions.

It is well established that transmitters of the nonadrenergic-noncholinergic (NANC) system are involved in the control of sexual arousal and penile erection in healthy males. The proerectile activity of dopamine D1/D2 receptor agonist apomorphine-HCl (IXENSE, UPRIMA) involves oxytocinergic pathways descending from the hypothalamus to the brain stem and spinal autonomic centers. Although it has been demonstrated that injection of oxytocin into the paraventricular nucleus and the hippocampus produces penile erection in rats, the significance of the peptide in the control of sexual arousal and penile erection in man has been, up until now, only poorly evaluated. The present study was undertaken to determine whether oxytocin (OT) plasma levels alter in the systemic and cavernous blood of healthy males under different penile conditions (flaccidity, tumescence, rigidity, detumescence). Twenty-five healthy adult males were exposed to visual and tactile erotic stimuli in order to elicit penile tumescence and rigid erection. Blood was taken from the corpus cavernosum (CC) and the cubital vein (CV) during penile flaccidity, tumescence, rigidity and detumescence. Following extraction from plasma aliqouts, oxytocin was measured by means of a radioimmunoassay. An increase was observed in the mean OT plasma levels in the systemic and cavernous blood when the flaccid penis became tumescent (CC: from 66.7+/-34 to 75+/-44 pg/ml; CV: from 71+/-41 to 79+/-49.5 pg/ml). From tumescence to rigidity, OT further rose in the cavernous blood (to 81+/-58 pg/ml), whereas it remained unaltered in the systemic circulation. During detumescence, oxytocin plasma levels dropped in the cavernous but again increased in the systemic blood (to 94+/-49 pg/ml). Our results support the hypothesis of a pivotal role of OT in the mechanism of male sexual arousal and penile erection and provide a rationale for the use of apomorphine in the treatment of erectile dysfunction.

Brain monoaminergic control of male reproductive behavior. III. Norepinephrine and the post-ejaculatory refractory period

The present study was performed to examine the role of brain norepinephrine in the control of copulation and the post-ejaculatory refractory period in the male rat. Disruption of central noradrenergic systems was achieved by (1) selective electrolytic lesion of noradrenergic cell bodies in the locus coeruleus or (2) administration of specific inhibitors of norepinephrine synthesis, sodium diethyldithiocarbamate (DDC) or 1-phenyl-3-(2-thiazolyl)-2 thiourea (U-14, 624). Electrolytic lesions of the locus coeruleus produced a significant increase in the duration of the post-ejaculatory refractory period and its concomitant 22-kHz ultrasonic vocalization. Administration of norepinephrine synthesis inhibitors significantly increased both mount and intromission latencies and caused a dramatic increase in the length of the post-ejaculatory refractory period. These findings support the hypothesis that norepinephrine-containing neural pathways are involved in the control of sexual arousal and suggest that a functional noradrenergic system is essential to the integrity of normal masculine copulatory behavior.

Identification of cues and control of sexual arousal by rapists

The experiments in this article pertain to factors relevant to rape. The first experiment examined the ability of four groups to discriminate between appropriate and inappropriate sexual cues. Rapists detected such cues as well as did either Normals or Non-rapist Inmates, in all but the most assaultive rape tape. Normal subjects who had consumed alcohol prior to testing, detected inappropriate cues earlier in the tapes than did all other subjects. The second experiment addressed the ability of subjects to inhibit sexual arousal when instructed to do so. Rapists and Non-rapists were shown to be equally capable of inhibiting arousal in response to both mutually-consenting and rape cues. These findings negate theories suggesting that rapists differ from other men in that they are unable to exert control over their arousal, and that they have difficulty in identifying inappropriate cues to arousal.

Pornography and attitude change

Sexual arousal to erotica (Levitt, 1969) has long been the concern of several organized groups in our society. Various legislative bodies have, as a result of prodding from some of their constituents, reacted to this phenomenon by passing various laws. These acts are generally directed toward the definition and control of sexual arousal and toward the control of the stimulus materials which are presumed to promote the arousal states. In passing such legislation, legislatures have made several assumptions, the more important being: 1. Sexual arousal not in the service of reproduction is a social problem. 2. Sexual arousal to certain classes of stimuli is somehow qualitatively different from arousal due to other classes. 3. Exposure to certain classes of visual stimuli causes a decline in morals and an ensuring increase in antisocial ideation. These assumptions have been made, in the past, so as to justify such anti-obscenity measures as book-burning, boycotts, and legal controls. Of the latter, it has been said that: The very fact that every state, except one, as well as the federal government have passed some form of censorship law with respect to pornography is itself testimony independently given by many people over a long period of time that pornography does have some sort of influence. (Schmidt, 1957) Implied here is that obscenity does influence morals, behavior, or both, and that the various levels of government are acting upon evidence of this influence so as to protect the well-being of the people. The empirical evidence relating to the assumptions listed above, which are implicit in all obscenity statutes, was reviewed by Cairns, et al, (1961-1962) for the period 1925 to 1961. They found no direct test of the central assumption the causal relationship between exposure to obscene materials and anti-social behavior. A similar finding has been reported by Mann (1968). He reviewed the relevant literature for the period 1961 to 1968. Both authors reported that while sexual arousal may be induced by many diverse kinds of stimuli,

Information as a defensive control of sexual arousal.

Information as a defensive control of sexual arousal.