The Effect of oxytocin and interaction with adrenergic system on sexual Behavior in Adult male Rats

Oxytocin is a nanopeptide hormone which synthesis in paraventricular and supraoptic nucleus of hypothalamus. It is involved in the regulation of the numerous processes associated with reproductive functions and probably sexual behavior. In the present study, the effect of oxytocin and its interaction with adrenergic agonist on sexual behavior in adult male rats was studied. 56 adult male rats of the wistar race with 200-220gr weight were used in this study. All the rats were divided into 7 groups. Five groups were considered as experimental groups and rest considered as sham and control groups. The control group without any injected considered as control group and normal saline as solvent of oxytocin was injected into sham group. 100, 200,300() of oxytocin was injected into three experimental groups and oxytocin (200) and pheylephrine (100)was injection into other experimental group. The last experimental group received oxytocin (200) and cloning (100) The drugs were injected Intraperitoneally for 20 days and then several parameters related to the sexual behavior were evaluated during this period. The results obtained from this study were statistically analyzed using the tukey test and t-test methods. The results obtained from analysis of the data indicated that the Mount labtency (ML), Intromission latency (IL), post ejaculatory interval (PEI), Mount frequency(MF)and Ejaculatory latency(EL)significantly decreased in the injected groups with 100 and 200() of the oxytocin and also 200() of the oxytocin with 100() phenylephrine compared to control group,while Intromission frequency (IF), Copulatory efficacy(CE) and Inter copulatory interval (ICI) in the injected groups with 100 and 200 ()of the oxytocin and also 200 () of the oxytocin with 100 () phenylephrine signifrcantly increased compared to control group. According to our finding sexual motiveation and sexual performance increased by oxytocin alone and oxytocin with phenylephrine to interpret of the data, it should be noted that rate of sexual behavior depended to release of the LHRH from central nervous system. It means, release of nitric oxide synthase and PGE2 from nervous system induce increase of release LHRH from hypothalamus and activated pituitary gonad axis. In addition probably oxytocin could be increased sexual behavior via its impact on nervous system centers related to sexual behavior,such as dorsalis media nucleus and the preoptic area of hypothalamus.