Animal models of female sexual dysfunction: basic considerations on drugs, arousal, motivation and behavior

Female sexual dysfunctions are a heterogeneous group of symptoms with unknown but probably varying etiology. Social factors may contribute both to the prevalence and to the origin of these dysfunctions. The present review focuses on female hypoactive sexual desire disorder, sexual arousal disorder and orgasmic disorder. These disorders are generally the most common, according to epidemiological studies, and they can all be considered as disorders of motivation. An incentive motivational model of sexual behavior, applicable to humans as well as to non-human animals, is described and the dysfunctions placed into the context of this model. It is shown that endocrine alterations as well as observable alterations in neurotransmitter activity are unlikely causes of the disorders. A potential role of learning is stressed. Nevertheless, the role of some transmitters in female rodent sexual behavior is analyzed, and compared to data from women, whenever such data are available. The conclusion is that there is no direct coincidence between effects on rodent copulatory behavior and sexual behavior in women. Based on these and other considerations, it is suggested that sexual approach behaviors rather than copulatory reflexes in rodents might be of some relevance for human sexual behavior, and perhaps even for predicting the effects of interventions, perhaps even the effects of drugs. Female copulatory behaviors, including the proceptive behaviors, are less appropriate. The common sexual dysfunctions in women are not problems with the performance of copulatory acts, but with the desire for such acts, by feeling aroused by such acts and experiencing the pleasure expected to be caused by such acts. Finally, it is questioned whether female sexual dysfunctions are appropriate targets for pharmacological treatment.