ABSTRACT
Doramectin (DOR) is an antiparasitic drug that is widely used in domestic animals. In mammals, DOR acts as a γ-aminobutyric acid receptor agonist. This neurotransmitter plays an important role in the regulation of sexual behavior. The present study investigated the effects of two medically relevant doses of DOR on sexual behavior in male rats. We also examined whether previous sexual experience modulates responses to DOR. General activity was first observed in an open field 24, 48, and 72 h after administration of 0.1 and 0.3 mg/kg DOR to determine the dose and time effects of the drug. Apomorphine-induced penile erection and sexual behavior in inexperienced male rats were then analyzed. The effects of previous sexual experience on subsequent sexual behavior in DOR-treated rats (0.3 mg/kg, 24 h prior to the test) were also assessed. The standard therapeutic dose (0.2 mg/kg) did not modify general activity or penile erection. A slightly concentrated dose of 0.3 mg/kg, which is still within the therapeutic range, decreased apomorphine-induced penile erection, whereas 0.2 mg/kg did not modify this behavior. Compared with controls, sexual behavior in inexperienced male rats was impaired after 0.3 mg/kg DOR. Previous sexual experience had little impact on the effects of 0.3 mg/kg DOR. In conclusion, the 0.2 mg/kg dose of DOR did not affect motor behavior or apomorphine-induced penile erection. At a more slightly higher dose level, the appetitive and consummatory phases of sexual behavior in inexperienced male rats were impaired. Previous sexual experience was unable to reverse this sexual impairment, suggesting that previous sexual experience does not exert a positive effect in attenuating sexual impairment produced by DOR treatment.
Subject(s)
Anthelmintics/adverse effects , Ivermectin/analogs & derivatives , Penile Erection/drug effects , Sexual Behavior, Animal/drug effects , Animals , Apomorphine/antagonists & inhibitors , Apomorphine/pharmacology , Dose-Response Relationship, Drug , Ivermectin/adverse effects , Male , Motor Activity/drug effects , RatsABSTRACT
The dichloromethane and n-butanol extracts obtained from fresh bulbs of Hippeastrum vittatum (Amaryllidaceae), collected in Southern Brazil, were evaluated for their cytotoxic activity in vitro against five human cell lines (HT29 colon adenocarcinoma, H460 non-small cell lung carcinoma, RXF393 renal cell carcinoma, MCF7 breast cancer, and OVCAR3 epithelial ovarian cancer), using the sulphorhodamine B assay. Both extracts showed potential antiproliferative activity. From CH(2)Cl(2) fraction, three alkaloids were isolated: lycorine, vittatine and montanine. The two last compounds were submitted to the antiproliferative assay and the highest level of cytotoxicity was found for the alkaloid montanine.
