A new female rat animal model for hypoactive sexual desire disorder; behavioral and pharmacological evidence.
BACKGROUND
Female sexual dysfunction (FSD) affects 33-48% of women. Female rats with low sexual activity might model FSD.


OBJECTIVE
In this study, we have investigated whether in a population of normal female rats, subpopulations of rats exist with different levels of sexual behavior.


METHODS
Sexually experienced, intact, estradiol-primed female rats were placed in an empty compartment adjacent to a compartment with a male. The females were allowed, during 30 minutes, to switch between the compartments via a hole through which only the females could pass (paced mating). Next, we investigated the acute effects on female sexual behavior of apomorphine, a D(1) - and D(2) -type dopamine receptor agonist, (+/-)-8-hydroxy-2-(dipropylamino)tetralin hydrobromide (± 8-OH-DPAT), a 5-HT1A receptor agonist, and paroxetine, a selective serotonin reuptake inhibitor.


METHODS
Time spent in compartments, proceptive behaviors, contact-return latencies, and percentages of exits were quantified.


RESULTS
Based on their behavior in the paced mating sex test, estradiol-primed, intact female rats can be divided into three groups: those that mostly avoid the male, a large middle group, and those that mostly approach the male. The avoiders also showed significantly less proceptive behavior than the male approachers. The sexual behavior of the females was relatively stable over time, suggesting the existence of different endophenotypes in female rats. Apomorphine and ± 8-OH-DPAT had an inhibiting effect on sexual behavior, but only females dosed with apomorphine showed a different response in avoiders and approachers, more inhibiting effect in avoiders than approachers. Paroxetine had no effect on proceptive behavior.


CONCLUSIONS
The stable, male-avoiding behavior of some females might correspond to the characteristics of women with FSD. Therefore, these avoiders are a promising new model for FSD, specifically for sexual desire and/or arousal disorders. Furthermore, the apomorphine data suggest that differences in the dopamine system may (partly) underlie the differences in sexual behaviors between avoiders and approachers.
Snoeren
Eelke M S
EM
Department of Psychopharmacology, Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, the Netherlands. djhensel@iupui.edu
Chan
Johnny S W
JS
de Jong
Trynke R
TR
Waldinger
Marcel D
MD
Olivier
Berend
B
Oosting
Ronald S
RS
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000494:pharmacology*; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D004195:Disease Models, Animal; D018491:Dopamine Agonists / Q000494:pharmacology*; D005260:Female; D008297:Male; D017374:Paroxetine / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D058825:Serotonin 5-HT1 Receptor Agonists / Q000494:pharmacology*; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology*; D012726:Sexual Behavior, Animal / Q000187:drug effects; D020018:Sexual Dysfunctions, Psychological / Q000503:physiopathology*
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D001058:Apomorphine; D018491:Dopamine Agonists; D017374:Paroxetine; D058825:Serotonin 5-HT1 Receptor Agonists; D017367:Selective Serotonin Reuptake Inhibitors