Pre-pregnancy stress suppressed the reproductive systems in parents and changed sex ratio in offspring

The impact of sleep deprivation on sexual behaviors and FAAH expression in the prefrontal cortex of male rats

Sleep deprivation (SD) causes alterations in the function of the endocannabinoid (EC) system and also results in alteration in many behaviors such as increased anxiety, deteriorated alertness, memory deficits, as well as sexual behaviors. Controversial data about the effects of SD on sexual response are provided. Fatty acid amide hydrolase (FAAH), the enzymes involved in the degradation of the EC system play an important role in the function of the EC system. This study aimed to investigate the effect of REM SD (RSD) and total SD (TSD) on the sexual behaviors and FAAH expression in the prefrontal cortex (PFC) of male rats. RSD was carried out through the flower pot technique for 24 h and 48 h, and TSD also was induced by keeping awake the rats by gentle handling for 6 h. Immediately after RSD and TSD, sexual behaviors were recorded for 45 min. Sexual behaviors were reduced by both types of RSD and TSD. The deleterious effects of 24 h RSD were more severe compared with 6 h of TSD. Serum testosterone concentration was significantly higher after TSD but not RSD compared to the normal sleep (NS) group. FAAH expression in the PFC was significantly reduced after both RSD and TSD compared to the NS group. Given that the function of the EC system has been previously shown to change different behaviors such as sexual activity, our results could suggest that behavioral effects of both types of SD on sexual behavior may partially result from activation of this signaling pathway by the reduction of FAAH in the PFC.

Exposure to high male density causes maternal stress and female-biased sex ratios in a mammal

A shift from the traditional perspective that maternal stress is invariably costly has instigated recent interest into its adaptive role in offspring sex allocation. Stress generated by social instability has been linked to offspring sex ratio biases that favour the production of female offspring, which converges with the theoretical prediction that mothers in the poor condition are better off investing in daughters rather than sons. However, previous research has failed to disentangle two different processes: the passive consequence of maternal stress on sex-specific mortality and the adaptive effect of maternal stress at the time of conception. Here, I show that exposure to high male density social conditions leads to elevated stress hormone levels and female-biased in utero offspring sex ratios in house mice (Mus musculus domesticus), and identify that sex-specific offspring production-not sex-specific mortality-is the mechanism accounting for these sex ratio skews. This outcome reflects the optimal fitness scenario for mothers in a male-dominated environment: the production of daughters, who are guaranteed high mate availability, minimizes male-male competition for their sons. Overall, this study supports the idea that maternal stress has the potential to be adaptive and advances our understanding of how exposure to different social conditions can influence sex allocation in mammals.

Maternal stress in sheep during late pregnancy influences sperm quality in early puberty of the offspring

Stress at the end of sheep gestation can damage the reproductive development of young males. The aim of the present study was to evaluate the effects of LPS administration in the last third of sheep pregnancy on the reproductive parameters of prepubertal rams. Thirty-six pregnant nulliparous ewes (12 ± 2 months old; 45 ± 6 kg) were assigned to two treatments, LPS (E. coli; 0.8 μg kg^-1) and control (placebo/saline) administered in late pregnancy (120 days post-conception). The animals gave birth to 17 male lambs (11 LPS; 8 control). Reproductive development of the young rams was analyzed from 5 to 12 months of age. A completely randomized design in double factorial scheme was used. The data were analyzed by analysis of variance. The model included treatment (LPS; control), age as main effects and their interactions, and the animal as a repeated measure. Means were compared by the PDIFF-SAS (Pr > |t|) at P < 0.05. An effect of age was observed for scrotal circumference, testicular consistency, homogeneity of testicular parenchyma, vascularization, semen quantity and quality, and blood testosterone concentration (P < 0.05). LPS increased sperm defects (P < 0.05) but an interaction with age was not observed (P > 0.05) with higher abnormalities only during months 8 and 9 (P < 0.05) and not thereafter. In summary, LPS did not cause long-term damage to testicular morphology analyzed from the onset of puberty to sexual maturity. However, LPS treatment affected sperm morphology during early puberty of the offspring.

Prenatal stress and elevated seizure susceptibility: Molecular inheritable changes

Stressful episodes are common during early-life and may have a wide range of negative effects on both physical and mental status of the offspring. In addition to various neurobehavioral complications induced by prenatal stress (PS), seizure is a common complication with no fully explained cause. In this study, the association between PS and seizure susceptibility was reviewed focusing on sex differences and various underlying mechanisms. The role of drugs in the initiation of seizure and the effects of PS on the nervous system that prone the brain for seizure, especially the hypothalamic-pituitary-adrenal (HPA) axis, are also discussed in detail by reviewing the papers studying the effect of PS on glutamatergic, gamma-aminobutyric acid (GABA)ergic, and adrenergic systems in the context of seizure and epilepsy. Finally, epigenetic changes in epilepsy are described, and the underlying mechanisms of this change are expanded. As the effects of PS may be life-lasting, it is possible to prevent future psychiatric and behavioral disorders including epilepsy by preventing avoidable PS risk factors.

The Adaptive Sex in Stressful Environments

The impact of early stress on juvenile development has intrigued scientists for decades, but the adaptive significance of such effects remains an ongoing debate. This debate has largely ignored some characteristics of the offspring, such as their sex, despite strong evolutionary and demographic implications of sex-ratio variation. We review recent studies that examine associations between glucocorticoids (GCs), the main class of stress hormones, and offspring sex. Whereas exposure to GCs at around the time of sex determination in fish consistently produces males, the extent and direction of sex-ratio bias in response to stress vary in reptiles, birds, and mammals. We propose proximate and ultimate explanations for most of these trends.