RESUMO
INTRODUCTION: The multiple partner choice arena (MPCA) is an experimental setup in which male rats display a significant shortening of ejaculation latency, which is the main characteristic of premature ejaculation (PE) in men. Thus, the MPCA is a potential animal model for PE. AIM: In this study, we further analyze whether the features of the MPCA satisfy the validity criteria for it to be considered an animal model as well as the possible participation of the serotoninergic system in the faster ejaculation exhibited by male rats in the MPCA. METHODS: In Experiment 1, male rats were tested in a standard arena to assess their sexual behavior, then were assessed 1 week later in the MPCA. Another group was first tested in the MPCA, then in a standard arena. In Experiment 2, male rats divided into two groups were treated daily with WAY-100635 (5-HT(1A) antagonist) or vehicle for 15 days. In each group, half of the subjects were tested in a standard arena and half were tested in the MPCA on days 1, 8, and 15 of treatment. MAIN OUTCOME MEASURES: Number of intromissions and intromission and ejaculation latencies were the main outcome measures. RESULTS: In Experiment 1, males tested in the MPCA ejaculated significantly faster, regardless of the order in which they were evaluated in both arenas. In Experiment 2, the administration of WAY-100635 increased intromission and ejaculation latencies, and the number of intromissions in the MPCA. CONCLUSIONS: The results obtained in the MPCA support its use as an animal model for PE evaluation.
Assuntos
Comportamento de Escolha/fisiologia , Ejaculação/fisiologia , Ejaculação Precoce/fisiopatologia , Comportamento Sexual Animal/fisiologia , Animais , Modelos Animais de Doenças , Feminino , Masculino , Piperazinas/farmacologia , Piridinas/farmacologia , Ratos , Ratos WistarRESUMO
OBJECTIVE: In order to clarify the effect of the prenatal (PN) treatment of the drug 1,4,6-androstatriene-3,17-dione (ATD) which blocks the conversion of testosterone into estradiol on male sexual behavior of the rats offsprings, from the effect of the mild stress induced by the PN administration of the Propylene glycol (PG), the vehicle used to dissolve ATD. METHODS: Pregnant Wistar rats were divided into three groups. The CON group did not receive any kind of treatment. The other two groups (PG and ATD) were injected i.p. during gestation (days 11-22) with 0 and 5 mg of ATD, dissolved in 0.1 ml of PG, respectively, doses reported by other authors. Sexual performance of the male pups was analyzed three months later in four successive tests. RESULTS: In the first sexual test of these naive rats, the percentage of males mounting, intromitting, ejaculating and the ejaculation frequency of the ATD group decreased significantly in comparison with the CON group. Also in the first and 4th tests, mounting, intromission and ejaculation latencies, as in the post-ejaculatory refractory period, ATD group, was significantly longer in comparison with the CON group. PG males showed a male sexual behavior (MSB) similar to that observed in the ATD group, but the differences did not reach statistical significance when they were compared with the CON group. CONCLUSION: We considered that the PN stress induced by the daily administration of PG and ATD, results in a slower execution of the MSB in both groups and avoid distinguish the effect of the ATD. Then chronic PN injections, as a route of administration, could act as mild stressor and may have additive effects on drugs affecting brain sexual differentiation.