Bruno Carlo Cerpa Aranda

Effects of neonatal handling on social memory, social interaction, and number of oxytocin and vasopressin neurons in rats

Early-life environmental events can induce profound long-lasting changes in several behavioral and neuroendocrine systems. The neonatal handling procedure, which involves repeated brief maternal separations followed by experimental manipulations, reduces stress responses and sexual behavior in adult rats. The purpose of this study was to analyze the effects of neonatal handling on social behaviors of male and female rats in adulthood, as manifest by the results of social memory and social interaction tests. The number of oxytocin (OT) and vasopressin (VP) neurons in the paraventricular (PVN) and supraoptic (SON) nuclei of hypothalamus were also analyzed. The results did not demonstrate impairment of social memory. Notwithstanding, handling did reduce social investigative interaction and increase aggressive behavior in males, but did not do so in females. Furthermore, in both males and females, handling was linked with reduced number of OT-neurons in the parvocellular region of the PVN, while no differences were detected in the magnocellular PVN or the SON. On the other hand, handled males exhibited increased number of VP-neurons in the magnocellular zone of the PVN. We may conclude that the repeated brief maternal separations can reduce affiliative social behavior in adult male rats. Moreover, the disruption of the mother-infant relationship caused by the handling procedure induced long-lasting morphological changes in critical neuroendocrine areas that are involved in social bonding in mammals.

The impact of maternal consumption of cafeteria diet on reproductive function in the offspring

Maternal obesity is a risk factor for the development of metabolic syndrome and childhood obesity, and early overnutrition seems to induce the development of pathologies in adulthood, including insulin resistance, cardiovascular diseases, type 2 diabetes mellitus, and a higher BMI. In addition, it is known that obesity can negatively affect fertility and reproductive function in men. The objective of this work was to investigate the impact of maternal obesity induced by the consumption of cafeteria diet on metabolic, endocrine and reproductive outcomes in the male offspring. Body weight, abdominal fat content and concentrations of insulin, leptin, glucose and total cholesterol were analyzed in dams. The same parameters were evaluated in pups when in adulthood, in addition to the analysis of sexual behavior, followed by measurement of plasma luteinizing hormone, follicle-stimulating hormone, testosterone, and prolactin. Maternal consumption of cafeteria diet affected reproductive hormone regulation in the offspring and such modifications were reflected on sexual performance. Also, these modifications were independent of time and of the reproductive period during which dams consumed the diet. Our results indicate, for the first time, that maternal nutrition may have a deep impact on the reproductive function of the adult male offspring.