REM sleep deprivation does not increase the sexual behaviors of male rats

Using several measures of sexual activity, 24 male and 30 female Sprague-Dawley rats were subjected to a pretreatment test and 3 posttests (immediate and Recovery Days 4 and 7) following REM sleep deprivation in a water tank. With careful controls, sexual activity was not significantly affected by the sleep treatments. Data do not support motivational hypotheses.     

Effects of different substance misuse in genital reflexes of paradoxical sleep deprived male rats

As psychostimulants are widely abused, their neurochemical and behavioral effects have been extensively studied for many years. Our previous data demonstrate that paradoxical sleep deprivation (PSD) enhances drug-induced penile erection and ejaculation. PSD in association to drugs of abuse like cocaine potentiated genital reflexes in male rats. In this sense, the present study investigated if three substances abused by young people--such as Delta(9)-tetrahydrocannabinol (Delta(9)THC), alcohol and caffeine--had any significant effect on the genital reflexes in PSD rats. The results indicated that PSD induced erection in 50% of the rats and 20% ejaculated. In addition, there was no significant alteration in the number of animals exhibiting genital reflexes neither on the frequency of these behaviors when challenged with Delta(9)-THC or alcohol or caffeine after 96 h of PSD. These findings show that Delta(9)THC, alcohol and caffeine when administrated isolated did not produce alterations in genital reflexes in the PSD male rats.     

Perinatal bromopride treatment: effects on sexual behavior of male and female rats

Effects of different perinatal bromopride treatments on sexual behavior were examined in adult male and female rats of Wistar origin. Female rats of mothers treated with bromopride (BRO) during lactation (VB group) and during pregnancy and lactation (BB group) showed lower lordosis quotients than those of controls (VV group). Females of mothers treated with BRO only during pregnancy (BV group) showed no differences in lordosis quotient when compared to the VV group. There were no significant differences in male sexual behavior between experimental and control groups. The effect of bromopride on the control of sexual behavior is discussed.     

The effect of ethanol treatment on social behavior in male rats

The effect of 0.50 g/kg of EtOH in male rats interacting with a stimulus male juvenile in a newly developed test of social interaction was examined. The adult male rats were treated with EtOH (8.0 to 12.0 g/kg/day) or equicaloric dextrin maltose for 2 weeks (studies 1 and 2) or 8 weeks (study 3) and social interaction was assessed both before and after chronic drug treatment was ended in study 1 and after chronic drug treatment was ended in studies 2 and 3. It was found that prior to chronic drug treatment, in study 1, 0.50 g/kg of EtOH increased both aggressive behavior and time spent interacting with the stimulus juvenile male from the first presentation of the juvenile to the second presentation (20 min apart) while saline injection decreased it. After chronic drug treatment was ended, in study 1 animals treated chronically with EtOH were more aggressive when they were not intoxicated than when they had been treated with 0.50 g/kg of EtOH. In studies 2 and 3, after chronic drug treatment was ended, aggressive behavior and time spent interacting with the juvenile were greater in the animals treated chronically with EtOH, regardless of whether they were injected with saline or 0.50 g/kg of EtOH. The results of these studies showed that chronic EtOH treatment can produce long-lasting changes in social behavior after drug treatment is over and can alter the animal's normal response to EtOH in a social setting.     

The relationship between aggressive and sexual behavior in male mice: Effects of testosterone and parachlorophenylalanine

The purpose of this study was to clarify the connection between aggressive and sexual behavior with the aid of testosterone propionate (TP) and parachlorophenylalanine (PCPA). Previous studies have indicated that aggressive and sexual behavior are positively correlated, and it has been suggested that both behaviors are related to the level of general arousal. Testosterone has documented effects on both aggressive and sexual behavior. It has been hypothesized that these effects are due to an increased level of general arousal. If this is the case, aggressive and sexual behavior could be restored by administration of drugs excitating the central nervous system, e.g., PCPA. The present study examined the effects of TP and PCPA on aggressive and sexual behavior in gonadectomized male mice. Control animals were injected with sesame seed oil or saline. The level of aggressiveness was assessed by means of dyadic tests with gonad-intact male opponents. For the sexuality tests, a receptive female was placed in the home cage of the experimental male. The results showed that male mice injected with PCPA were more aggressive than the males of the other groups, while the TP-exposed males expressed the most sexual activity. Compared to the control group, the PCPA and TP groups were more active in both the aggression and the sexuality tests. These findings lend support to the hypothesis that the earlier documented correlations between aggressive and sexual behavior could be due to both behaviors being dependent on a certain level of general activation. Aggr. Behav. 24:367–377, 1998. © 1998 Wiley-Liss, Inc.     

Possible participation of D3 and D4 dopaminergic receptors on genital reflexes induced by cocaine in paradoxical sleep deprived male rats

Previous studies have demonstrated that paradoxical sleep deprivation (PSD) potentiates cocaine-induced genital reflexes in male rats and both D1 and D2 receptors may play a role in those effects, and to examine the possibility that such might involve other dopaminergic receptors, we investigated the effects of D3 and D4 receptor subtype antagonists on cocaine-induced reflexes in sleep-deprived rats. Separate groups of PSD rats received saline, D3 (U9919A; 0.75, 1.5 and 3 mg/kg) or D4 (L745870; 0.75, 1.5 and 3 mg/kg) antagonists prior to acute cocaine challenge. Results demonstrated that U9919A induced significant reduction in the number of animals that displayed erection and the frequency of erection at two smaller doses, while no significant difference was reported for the D4 receptor antagonist. Although our studies indicate that there is a relevant participation of D3 receptors in male sexual function, D4 receptors seem not to exert an essential role in this model.