LUSTSexuality Systems

Perhaps in this "Age of Viagra" new sexuality-facilitating agents are no longer needed. However, one could argue that beside the "mechanical aid" offered by such nitric oxide facilitating, erection-sustaining substances, there is still a substantial need for agents that facilitate the psychological side of eroticism. Based on preclinical work in animals, it is to be anticipated that certain neuropeptides and steroids may be harnessed to facilitate such ends. An abundance of neuropeptides and steroids have been identified within the fundamental sexual circuits concentrated in subcortical regions of the mammalian brain (Pfaff, 1999). For some time, it has been evident that testosterone supplementation can strengthen sexual urges in both males and females (Crenshaw and Goldberg, 1996).

The neuropeptide that has received the most attention is leutenizing hormone release hormone (LHRH). However, despite very promising animal results, human trials have been largely disappointing (Moss and Dudley, 1984). Whether this is simply due to the fact that this molecule does not penetrate to the right parts of the human brain or whether it requires the support of other psychosocial stimuli is unknown. However, nonpeptide congeners for this peptide receptor system could be developed and evaluated more systematically in psychological contexts that support erotic urges, perhaps in combination with mild facilitation of other systems such as the opioids, which figure heavily in various forms of pleasure as well as social confidence (Panksepp et al., 1985; van den Berg et al., 2000).

The most prominent additional neuropeptide systems implicated in sociosexual feelings and desires are the brain systems that utilize the posterior-pituitary nona-peptides oxytocin (OXY) and arginine-vasopressin (AVP). Oxytocinergic activity within the brain is substantially facilitated by the more female-specific adult sex hormones, estrogen and progesterone, while AVP systems are promoted by the more male-specific adult sex hormone testosterone. In animal models, OXY promotes female sexual behavior, but it is also compatible with male sexual urges, perhaps because the molecule is not only a general social hormone within the brain (Insel, 1997) but is released markedly by pleasurable somatosensory stimulation and at orgasm (Carter, 1998; Uvnas-Moberg, 1998). Thus, it would be anticipated that under the right contextual conditions (i.e., those that support eroticism), oxytocinergics that get to the right regions of the brain, perhaps even via intranasal routes, would tend to increase intimacy and the quality of sociosexual interactions. On the other hand, AVP diminishes female sexual behavior, while promoting male sexual urges (Sodersten et al., 1983). If it turns out that this latter effect is reflected largely in appetitive craving as opposed to erotic affects, AVP systems may not be a desirable target for drug development. Of course, peripherally active agents for both types of neuropeptide agonists may yield potentially troublesome antidiuretic and smooth-muscle stimulatory effects.

On the other hand, based on preclinical data, an AVP antagonist might serve as a drug for treatment of sexual aggression, including that seen in the context of sexual jealousy. In mice, this peptide has been found to mediate the attachments that males develop to females with whom they have copulated. Indeed, placement of AVP into the brains of male mice in the presence of females helps establish social preferences so strong that they subsequently exhibit intense aggression toward intruding males (Winslow et al., 1993). From an affective perspective, this may reflect a jealousy type of psychological response. Considering the amount of human aggression that arises in the context of sexual jealousy, it is worth considering whether antagonists for the human AVP system might diminish such obsessive, irritable feelings.

Dealing With Erectile Dysfunction

Dealing With Erectile Dysfunction

Whether you call it erectile dysfunction, ED, impotence, or any number of slang terms, erection problems are something many men have to face during the course of their lifetimes.

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