Increased vulnerability to ethanol consumption in adolescent maternal separated mice
ADDICTION BIOLOGY
Authors: Garcia-Gutierrez, Maria S.; Navarrete, Francisco; Aracil, Auxiliadora; Bartoll, Adrian; Martinez-Gras, Isabel; Lanciego, Jose L.; Rubio, Gabriel; Manzanares, Jorge
Abstract
The purpose of this study was to evaluate the effects of early life stress on the vulnerability to ethanol consumption in adolescence. To this aim, mice were separated from their mothers for 12 hours/day on postnatal days8 and 12. Emotional behavior (light-dark box, elevated plus maze and tail suspension tests) and pre-attentional deficit (pre-pulse inhibition) were evaluated in adolescent maternal separated (MS) mice. Alterations of the corticotropin-releasing factor (CRF), glucocorticoid receptor (NR3C1), tyrosine hydroxylase (TH), mu-opioid receptor (MOr), brain-derived neurotrophic factor (BDNF), neuronal nuclei (NeuN), microtubule-associated protein 2 (MAP2) and neurofilament heavy (NF200)-immunoreactive fibers were studied in the paraventricular nucleus of the hypothalamus (PVN), ventral tegmental area (VTA), nucleus accumbens (NAc) or hippocampus (HIP). The effects of maternal separation (alone or in combination with additional stressful stimuli) on ethanol consumption during adolescence were evaluated using the oral ethanol self-administration paradigm. MS mice presented mood-related alterations and pre-attentional deficit. Increased CRF, MOr and TH, and reduced BDNF, NR3C1, NeuN, MAP2 and NF200-immunoreactive fibers were observed in the PVN, NAc and HIP of adolescent MS mice. In the oral ethanol self-administration test, adolescent MS mice presented higher ethanol consumption and motivation. Exposure to additional new stressful stimuli during adolescence significantly increased the vulnerability to ethanol consumption induced by maternal separation. These results clearly demonstrated that exposure to early life stress increased the vulnerability to ethanol consumption, potentiated the effects of stressful stimuli exposure during adolescence on ethanol consumption and modified the expression of key targets involved in the response to stress, ethanol reinforcing properties and cognitive processes.
Placental Gene Expression and Offspring Temperament Trajectories: Predicting Negative Affect in Early Childhood
JOURNAL OF ABNORMAL CHILD PSYCHOLOGY
Authors: Finik, J.; Buthmann, J.; Zhang, W.; Go, K.; Nomura, Y.
Abstract
Exposure to prenatal stress increases offspring risk for long-term neurobehavioral impairments and psychopathology, such as Attention Deficit Hyperactivity Disorder (ADHD). Epigenetic regulation of glucocorticoid pathway genes may be a potential underlying mechanism by which maternal conditions 'program' the fetal brain for downstream vulnerabilities. The present study aims to investigate whether mRNA expression of glucocorticoid pathway genes in the placenta predict offspring negative affect during early childhood (between 6 and 24 months). Participants include 318 mother-child dyads participating in a longitudinal birth cohort study. Placental mRNA expression of glucocorticoid pathway genes (HSD11B1, HSD11B2, NR3C1, NCOR2) were profiled and negative affect traits of the offspring were measured at 6, 12, 18, and 24 months. HSD11B1 mRNA expression significantly predicted negative affect (beta = -.09, SE = .04; p = .036), and Distress to Limitations trajectories (beta = -.13, SE = .06; p = .016). NCOR2 mRNA expression significantly predicted Distress to Limitations (beta = .43, SE = .21; p = .047), and marginally predicted Sadness trajectories (beta = .39, SE = .21; p = .068). HSD11B2 and NR3C1 did not predict trajectories of Negative Affect or subscale scores. Infant negative affect traits were assessed via maternal self-report, and deviated from linearity across follow-up. mRNA expression of glucocorticoid pathway genes in the placenta may be a potentially novel tool for early identification of infants at greater risk for elevated negative affect. Further study is needed to validate the utility of mRNA expression of glucocorticoid pathway genes in the placenta.