INTRODUCTION: Flibanserin is a mixed 5-HT1A agonist/5-HT2A antagonist that has 
been developed for the treatment of hypoactive sexual desire disorder in women.
AIM: To assess the acute and chronic dose-response effects of flibanserin on 
measures of sexual desire and copulation in ovariectomized rats primed with 
estradiol benzoate (EB) alone or in combination with progesterone (P).
METHODS: In Experiment 1, sexually experienced ovariectomized (OVX) rats at one 
testing site were rendered fully sexually receptive with EB + P priming and 
tested weekly with a sexually active male in bi-level pacing chambers following 
daily flibanserin treatment for 28 days. In Experiment 2, sexually experienced 
OVX rats at a different testing site received EB alone and were tested weekly 
with sexually active males following daily flibanserin treatment.
MAIN OUTCOME MEASURES: Female appetitive behaviors (solicitations, hops and 
darts, anogenital investigations), defensive behaviors, pacing, lordosis, and 
male copulatory responses (intromissions and ejaculations) were measured during 
each 30-minute copulation test.
RESULTS: Acute flibanserin or 1 week of chronic flibanserin treatment did not 
modify sexual responses in fully (EB + P) or partially (EB-alone) primed 
females. After 2 weeks of chronic treatment, fully primed females displayed 
significantly more solicitations than the three other groups. After 3 weeks of 
chronic treatment, a significant increase in female solicitations was observed 
in both hormone-treatment groups.
CONCLUSION: This study shows the first evidence that chronic, but not acute, 
flibanserin treatment augments appetitive sexual behaviors in OVX female rats 
primed with EB + P or EB alone. Given the positive effect of flibanserin in 
clinical trials, these results confirm previous reports that solicitations in 
the female rat are a predictive animal model of human female sexual desire.