Influence of ω3 fatty acids on maternal behavior and brain oxytocin in the murine perinatal period.

INTRODUCTION: Perinatal women often experience mood disorders and postpartum depression due to the physical load and the rapid changes in hormone levels caused by pregnancy, childbirth, and nursing. When the mother's emotions become unstable, their parental behavior (maternal behavior) may decline, the child's attachment may weaken, and the formation of mother-child bonding can become hindered. As a result, the growth of the child may be adversely affected. The objective of this study was to investigate the effect of ω3 fatty acid deficiency in the perinatal period on maternal behavior and the oxytocin concentration and fatty acid composition in brain tissue. MATERIALS AND METHODS: Virgin female C57BL/6 J mice fed a ω3 fatty acid-deficient (ω3-Def) or adequate (ω3-Adq) diet were mated for use in this study. To assess maternal behavior, nest shape was evaluated at a fixed time from gestational day (GD) 15 to postpartum day (PD) 13, and a retrieval test was conducted on PD 3. For neurochemical measurement, brains were removed from PD 1-6 dams and hippocampal fatty acids and hypothalamic oxytocin concentrations were assessed. RESULTS: Peripartum nest shape scores were similar to those reported previously (Harauma et al., 2016); nests in the ω3-Def group were small and of poor quality whereas those in the ω3-Adq group were large and elaborate. The inferiority of nest shape in the ω3-Def group continued from PD 0-7. In the retrieval test performed on PD 3, dams in the ω3-Def group took longer on several parameters compared with those in the ω3-Adq group, including time to make contact with pups (sniffing time), time to start retrieving the next pup (interval time), and time to retrieve the last pup to the nest (grouping time). Hypothalamic oxytocin concentrations on PD 1-6 were lower in the ω3-Def group than in the ω3-Adq group. DISCUSSION: Our data show that ω3 fatty acid deficiency reduces maternal behavior, a state that continued during pup rearing. This was supported by the observed decrease in hypothalamic oxytocin concentration in the ω3-Def group. These results suggest that ω3 fatty acid supplementation during the perinatal period is not only effective in delivering ω3 fatty acids to infants but is also necessary to activate high-quality parental behavior in mothers.

Effects of Prenatal Phthalate Exposure and Childhood Exercise on Maternal Behaviors in Female Rats at Postpartum: A Role of Oxtr Methylation in the Hypothalamus.

Both the detrimental effect of prenatal exposure to di-(2-ethylhexyl)-phthalate (DEHP) and the beneficial effects of physical exercise on brain functions have been reported. The oxytocin pathway has been implicated in the onset of maternal behaviors. Epigenetic modification of the oxytocin receptor gene (OXTR) through DNA methylation has been associated with the pathogenesis of neuropsychiatric disorders. The purpose of this study was to investigate the effects of prenatal DEHP exposure on oxytocin-regulated maternal behaviors and to examine the protective effect of exercise. Pregnant rats (F0) were fed with vehicle or DEHP during gestation and the offspring females (F1) were assessed for their maternal behaviors by pup retrieval test at postpartum. The results showed that reduced pup retrieval activities without significant alteration of stress responses were observed in the prenatally DEHP-exposed females. Prenatal DEHP exposure decreased the expressions of oxytocin, Oxtr mRNA, and oxytocin receptor, and increased Oxtr methylation in the hypothalamus of postpartum female rats. There were no significant effects of exercise on behavioral, biochemical, and epigenetic measurements. These results suggest that prenatal DEHP exposure has a long-term adverse effect on maternal behaviors; Oxtr hyper-methylation may be a potential epigenetic mechanism for this alteration, which cannot be prevented by physical exercise during childhood.

Multi- and Transgenerational Outcomes of an Exposure to a Mixture of Endocrine-Disrupting Chemicals (EDCs) on Puberty and Maternal Behavior in the Female Rat.

BACKGROUND: The effects of endocrine-disrupting chemicals (EDCs) on fertility and reproductive development represent a rising concern in modern societies. Although the neuroendocrine control of sexual maturation is a major target of EDCs, little is known about the potential role of the hypothalamus in puberty and ovulation disruption transmitted across generations. OBJECTIVES: We hypothesized that developmental exposure to an environmentally relevant dose of EDC mixture could induce multi- and/or transgenerational alterations of sexual maturation and maternal care in female rats through epigenetic reprograming of the hypothalamus. We investigated the transmission of a disrupted reproductive phenotype via the maternal germline or via nongenomic mechanisms involving maternal care. METHODS: Adult female Wistar rats were exposed prior to and during gestation and until the end of lactation to a mixture of the following 13 EDCs: di-n-butyl phthalate (DnBP), di(2-ethylhexyl) phthalate (DEHP), bisphenol A (BPA), vinclozolin, prochloraz, procymidone, linuron, epoxynaxole, dichlorodiphenyldichloroethylene, octyl methoxynimmate, 4-methylbenzylidene camphor (4-MBC), butylparaben, and acetaminophen. Perinatally exposed offspring (F1) were mated with unexposed males to generate germ cell (F2) and transgenerationally exposed (F3 and F4) females. Sexual maturation, maternal behavior, and hypothalamic targets of exposure were studied across generations. RESULTS: Germ cell (F2) and transgenerationally (F3) EDC-exposed females, but not F1, displayed delayed pubertal onset and altered folliculogenesis. We reported a transgenerational alteration of key hypothalamic genes controlling puberty and ovulation (Kiss1, Esr1, and Oxt), and we identified the hypothalamic polycomb group of epigenetic repressors as actors of this mechanism. Furthermore, we found a multigenerational reduction of maternal behavior (F1-F3) induced by a loss in hypothalamic dopaminergic signaling. Using a cross-fostering paradigm, we identified that the reduction in maternal phenotype was normalized in EDC-exposed pups raised by unexposed dams, but no reversal of the pubertal phenotype was achieved. DISCUSSION: Rats developmentally exposed to an EDC mixture exhibited multi- and transgenerational disruption of sexual maturation and maternal care via hypothalamic epigenetic reprogramming. These results raise concerns about the impact of EDC mixtures on future generations. https://doi.org/10.1289/EHP8795.

Opium Effect in Pregnancy on the Dynamics of Maternal Behavior: Testing a Neurochemical Model.

BACKGROUND: Investigations into neurochemical mechanisms of opioid addiction are difficult due to the complexity of behavior and multiplicity of involved neurotransmitter and hormonal systems. The aim of this study was to examine the benefits of structured analysis of these mechanisms using the framework of the neurochemical model Functional Ensemble of Temperament (FET) and the example of maternal behavior under the condition of opium consumption in pregnancy. The FET differentiates between (a) endurance, (b) speed of integration, and (c) emotionality aspects of behavior suggesting that these systems are differentially regulated by (a) serotonin-neuropeptides-brain-derived neurotrophic factor (BDNF), (b) dopamine-GABA, and (c) opioid receptor systems, correspondingly. The FET also suggests that mu-opioid receptors (MORs) binding the endorphines (including opium's ingredient morphine) have a stronger association with regulation endurance, whereas delta-OR have a stronger association with integration of behavior and kappa-OR - with the perceptual mobilization seen in anxiety. To test the predictions of this model, we compared the impact of massive MOR dysregulation on 3 behavioral aspects of behavior and on serotonin, BDNF, and corticosterone levels. METHODS: The study used 24 female white Wistar rats which were randomly divided into (1) control group: pregnant rats without any intervention; (2) opium-exposed group: animals that were exposed to opium during pregnancy and after the delivery until the end of the study. At the end of the study, the levels of BDNF, serotonin (5-HT) in the hippocampus of the mother's brain, and serum corticosterone, as well as 12 aspects of the maternal behavior were evaluated. The differences between control and experimental groups were assessed using the t test for independent samples. RESULTS: The BDNF and serotonin concentrations in the hippocampus of the mother rats which were exposed to opium were lower than in the control group; the mean corticosterone in exposed mothers was higher than in the control group. Behaviorally, opium-consuming mothers showed lower endurance in 4 distinct behavioral categories (nesting, feeding, grooming, and retrieval) than the mothers in the control group. Ease of integration of behavior was affected to a lesser degree, showing a significant effect only in 1 out of 5 applied measures. Self-grooming, seen as an emotionality-related aspect of behavior, was not affected. CONCLUSION: Opium exposure during pregnancy in our experiment primarily reduced the endurance of rat's maternal behavior, but the speed of integration of behavioral acts was less affected. This negative impact of opium on endurance was associated with a decrease of BDNF and serotonin levels in the hippocampus and an increase in corticosterone level in opium-consuming mothers. There is no effect of opium exposure on self-grooming behavior. This pattern supports the FET hypothesis about the role of 5-HT and BDNF in endurance, differential regulation of endurance, integrative and emotionality aspects of behavior, and differential association of the MOR system with endurance aspects, in comparison with kappa- and delta opioid receptors.

Silymarin administration during pregnancy and breastfeeding: evaluation of initial development and adult behavior of mice.

Silymarin is a phytotherapeutic agent derived from the species Silybum marianum (Asteraceae), commonly is known as milk thistle, and traditionally used as a hepatoprotective; however, recent studies have proposed its use in order to promote lactogenesis, but there are few reports of its effects on the development of offspring. Thus, the objective of this study was to evaluate the effect of silymarin treatment during pregnancy and breastfeeding on the sensory-somatic-motor development and adult behavior of F1-generation Swiss mice. The pregnant females of the parental generation were distributed in four experimental groups and treated orally with doses of 100, 200 or 300 mg/kg of silymarin, with a control group receiving vehicle - vegetable oil (VEH), to obtain the F1-generation. At the end of lactation, the parental generation were submitted to euthanasia. Body mass evolution was determined in both generations. The sensory-motor development of the offspring (F1-generation) was evaluated, and one male pup from each litter was followed up for an analysis of adult behavior. In the F1 analysis, no differences between the groups were observed in initial development from the sensory-somatic-motor analysis performed during the 1st to 21st postnatal days. In the behavioral evaluation of adults from the F1 generation, all the groups from dams treated with silymarin in open field (OF) analysis showed a decrease in the time spent in the periphery and an increase in the time spent in the center, but the ambulation observed by the number of quadrant crossed showed no difference. In addition, during OF, the 100 and 200 mg/kg groups presented an increase in fecal bolus compared with the VEH group. There was a decrease in immobility time in the forced swimming test in the 300 mg/kg group compared to the VEH group. Regarding the memory and learning test, the groups did not differ in their recognition scores. The results of this study using an animal model indicate that treatment with silymarin during pregnancy and breastfeeding does not promote significant morpho-functional changes in the offspring in their initial development and adult behavior, indicating the safety of its use during gestation and lactation.

Gestational folic acid supplementation does not affects the maternal behavior and the early development of rats submitted to neonatal hypoxia-ischemia but the high supplementation impairs the dam's memory and the Na+, K+ - ATPase activity in the pup's hippocampus.

Folic acid (FA) is a B-complex vitamin important to the development of the fetus, being supplemented during pregnancy. Our recent findings showed that gestation supplementation (normal and excess doses) prevented the cognitive deficits and BDNF imbalance in adult rats that were submitted to neonatal hypoxia-ischemia (HI). To better understand this protective effect, the present study aimed to evaluate whether FA supplementation could be related to (1) maternal behavior, memory and Na+, K+ - ATPase activity in the hippocampus of the dams; (2) on somatic growth, early neurobehavioral development and Na+, K+ - ATPase activity in the hippocampus of the offspring; and (3) the effects of this supplementation in pups submitted to neonatal HI. Pregnant Wistar rats were divided into three groups, according to the diet they received during gestation: standard diet (SD), supplemented with 2 mg/kg of FA (FA2 - normal dose) and supplemented with 20 mg/kg of FA (FA20 -excessive dose). At the 7th PND pups were submitted to the Levine-Vannucci model of HI. During weaning the maternal behavior, the somatic growth and the neurobehavior development of pups were assessed. After weaning, the memory of the dams (by the Ox-maze task) and the Na+, K+ - ATPase activity in the hippocampus of both dams and offspring were evaluated. Considering the dams (1), both doses of FA did not alter the maternal behavior or the Na+, K+ - ATPase activity in the hippocampus, but a memory deficit was observed in the high FA-supplemented mothers. Considering the offspring (2), both FA doses did not affect the somatic growth or the neurobehavior development, but the FA20 pups had a decreased Na+, K+ - ATPase activity in the hippocampus. The FA supplementation did not change the parameters evaluated in the HI rats (3) and did not prevent the decreased Na+, K+ - ATPase activity in the hippocampus of the HI pups. These results indicate that normal FA supplementation dose does not influence the maternal behavior and memory and does not impact on the offspring early development in rats. Further studies are needed to confirm the effects of the high FA supplementation dose in the dams' memory and in the Na+, K+ - ATPase activity in the hippocampus of the offspring.

Mice exposed to bisphenol A exhibit depressive-like behavior with neurotransmitter and neuroactive steroid dysfunction.

Fetal exposure to endocrine disrupting chemicals (EDCs) has been associated with adverse neurobehavioral outcomes across the lifespan and can persist across multiple generations of offspring. However, the underlying mechanisms driving these changes are not well understood. We investigated the molecular perturbations associated with EDC-induced behavioral changes in first (F1) and second (F2) filial generations, using the model EDC bisphenol A (BPA). C57BL/6J dams were exposed to BPA from preconception until lactation through the diet at doses (10 µg/kg bw/d-lower dose or 10 mg/kg bw/d-upper dose) representative of human exposure levels. As adults, F1 male offspring exhibited increased depressive-like behavior, measured by the forced swim test, while females were unaffected. These behavioral changes were limited to the F1 generation and were not associated with altered maternal care. Transcriptome analysis by RNA-sequencing in F1 control and upper dose BPA-exposed adult male hippocampus revealed neurotransmitter systems as major pathways disrupted by developmental BPA exposure. High performance liquid chromatography demonstrated a male-specific reduction in hippocampal serotonin. Administration of the selective serotonin reuptake inhibitor fluoxetine (20 mg/kg bw) rescued the depressive-like phenotype in males exposed to lower, but not upper, dose BPA, suggesting distinct mechanisms of action for each exposure dose. Finally, high resolution mass spectrometry revealed reduced circulating levels of the neuroactive steroid dehydroepiandrosterone in BPA-exposed males, suggesting another potential mechanism underlying the depressive-like phenotype. Thus, behavioral changes associated with early life BPA exposure may be mediated by sex-specific disruptions in the serotonergic system and/or sex steroid biogenesis in male offspring.

The genetic basis of parental care evolution in monogamous mice.

Parental care is essential for the survival of mammals, yet the mechanisms underlying its evolution remain largely unknown. Here we show that two sister species of mice, Peromyscus polionotus and Peromyscus maniculatus, have large and heritable differences in parental behaviour. Using quantitative genetics, we identify 12 genomic regions that affect parental care, 8 of which have sex-specific effects, suggesting that parental care can evolve independently in males and females. Furthermore, some regions affect parental care broadly, whereas others affect specific behaviours, such as nest building. Of the genes linked to differences in nest-building behaviour, vasopressin is differentially expressed in the hypothalamus of the two species, with increased levels associated with less nest building. Using pharmacology in Peromyscus and chemogenetics in Mus, we show that vasopressin inhibits nest building but not other parental behaviours. Together, our results indicate that variation in an ancient neuropeptide contributes to interspecific differences in parental care.

Prenatal exposure to integerrimine N-oxide impaired the maternal care and the physical and behavioral development of offspring rats.

Plants that contain pyrrolizidine alkaloids (PAs) have been reported as contaminants of pastures and food, as well as being used in herbal medicine. PAs are responsible for poisoning events in livestock and human beings. The aim of this present study was to evaluate effects of prenatal exposure to integerrimine N-oxide, the main PA found in the butanolic residue (BR) of Senecio brasiliensis, on both physical and behavioral parameters of Wistar rat offspring. The toxicity and maternal behavior were also evaluated. For this, pregnant Wistar rats received integerrimine N-oxide from the BR of Senecio brasiliensis, by gavage, on gestational days 6-20 (during organogenesis and fetal development period) at doses of 3, 6 and 9 mg/kg. During treatment, maternal body weight gain, and food and water intake were evaluated. After parturition, maternal behavior and aggressive maternal behavior were analyzed. In addition, physical development and behavioral assessments were observed in both male and female pups. Results showed that prenatal exposure to integerrimine N-oxide of S. brasiliensis induced maternal toxicity, impairment in maternal behavior and aggressive maternal behavior, mainly in the highest dose group. Between sexes comparison of pups showed loss of body weight, delayed physical development such as pinna detachment, hair growth, eruption of incisor teeth, eye and vaginal openings. These pups also showed a delay of palmar grasp, surface righting reflex, negative geotaxis and auditory startle reflexes. Thus, prenatal exposure to integerrimine N-oxide induces maternal toxicity, impairment of maternal care and delayed in physical and behavioral development of the offspring.

Sex-specific epigenetic disruption and behavioral changes following low-dose in utero bisphenol A exposure.

Bisphenol A (BPA) is an estrogenic endocrine disruptor widely used in the production of plastics. Increasing evidence indicates that in utero BPA exposure affects sexual differentiation and behavior; however, the mechanisms underlying these effects are unknown. We hypothesized that BPA may disrupt epigenetic programming of gene expression in the brain. Here, we provide evidence that maternal exposure during pregnancy to environmentally relevant doses of BPA (2, 20, and 200 µg/kg/d) in mice induces sex-specific, dose-dependent (linear and curvilinear), and brain region-specific changes in expression of genes encoding estrogen receptors (ERs; ERα and ERß) and estrogen-related receptor-γ in juvenile offspring. Concomitantly, BPA altered mRNA levels of epigenetic regulators DNA methyltransferase (DNMT) 1 and DNMT3A in the juvenile cortex and hypothalamus, paralleling changes in estrogen-related receptors. Importantly, changes in ERα and DNMT expression in the cortex (males) and hypothalamus (females) were associated with DNA methylation changes in the ERα gene. BPA exposure induced persistent, largely sex-specific effects on social and anxiety-like behavior, leading to disruption of sexually dimorphic behaviors. Although postnatal maternal care was altered in mothers treated with BPA during pregnancy, the effects of in utero BPA were not found to be mediated by maternal care. However, our data suggest that increased maternal care may partially attenuate the effects of in utero BPA on DNA methylation. Overall, we demonstrate that low-dose prenatal BPA exposure induces lasting epigenetic disruption in the brain that possibly underlie enduring effects of BPA on brain function and behavior, especially regarding sexually dimorphic phenotypes.

The CB1 cannabinoid receptor mediates glucocorticoid-induced effects on behavioural and neuronal responses during lactation.

It has been shown that glucocorticoids can modulate oxytocin (OT) secretion and disrupt maternal behaviour. Because the CB1 receptor (CB1R) has been implicated in some rapid glucocorticoid-induced actions, the present study aimed to evaluate the possible involvement of CB1Rs in maternal behaviour and neuronal activation during lactation. For this purpose, lactating female rats were pre-treated with dexamethasone (DEX) or saline, followed by treatment with AM251, a CB1R antagonist, or vehicle 90 min later. All of the experiments were performed 30 min after the administration of AM251 or vehicle. To evaluate maternal behaviour, the pups were returned to their home cages to the side of the cage opposite the previous nest after 12 h of separation and were filmed for the next 30 min. Aggressive behaviour was evaluated for 10 min following the placement of a male rat in the home cage. For the evaluation of behavioural performance, lactating rats were subjected to a T-maze and open-field tests. The amount of weight gained by the pups was evaluated 15 min after the onset of suckling to determine the amount of milk that they had obtained from the dam. In the central nervous system of lactating rats, c-Fos-positive nuclei were counted in the medial preoptic area, in both the ventral (v) and dorsal (d) parts of the median preoptic nucleus and in the bed nucleus of the stria terminalis (BNST). The number of neurons that were double-labelled for c-Fos/OT was counted in the medial magnocellular subdivision of the paraventricular nucleus, in the periventricular hypothalamic nucleus and in the supraoptic nucleus of the lactating rats. The results show that DEX had the following effects: (1) decreased the amount time the dam spent licking the pups, the amount of time the dam spent in an arched-nursing position and full maternal behaviour; (2) increased the latency to the first attack and decreased front attacks; (3) increased anxiety-like behaviour; and (4) decreased weight gain in the pups. In addition, DEX decreased neuronal activation in all of the investigated hypothalamic and forebrain areas. AM251 administration reversed these parameters, indicating that the behavioural effects and neuronal responses produced by DEX in lactating rats are likely to be mediated by CB1Rs.

Neonatal tryptophan depletion and corticosterone supplementation modify emotional responses in adult male mice.

The serotonergic system and the hypothalamic-pituitary-adrenal (HPA) axis are crucially involved in the regulation of emotions. Specifically, spontaneous and/or environmentally mediated modulations of the functionality of these systems early in development may favour the onset of depressive- and anxiety-related phenotypes. While the independent contribution of each of these systems to the emergence of abnormal phenotypes has been detailed in clinical and experimental studies, only rarely has their interaction been systematically investigated. Here, we addressed the effects of reduced serotonin and environmental stress during the early stages of postnatal life on emotional regulations in mice. To this aim, we administered, to outbred CD1 mouse dams, during their first week of lactation, a tryptophan deficient diet (T) and corticosterone via drinking water (C; 80µg/ml). Four groups of dams (animal facility rearing, AFR; T treated, T; C treated, C; T and C treated, TC) and their male offspring were used in the study. Maternal care was scored throughout treatment and adult offspring were tested for: anhedonia (progressive ratio schedule); anxiety-related behaviour (approach-avoidance conflict paradigm); BDNF, dopamine and serotonin concentrations in selected brain areas. T, C and TC treatments reduced active maternal care compared to AFR. Adult TC offspring showed significantly increased anxiety- and anhedonia-related behaviours, reduced striatal and increased hypothalamic BDNF and reduced dopamine and serotonin in the prefrontal cortex and their turnover in the hippocampus. Thus, present findings support the view that neonatal variations in the functionality of the serotonergic system and of HPA axis may jointly contribute to induce emotional disturbances in adulthood.

The effect of maternal multiple micronutrient supplementation on cognition and mood during pregnancy and postpartum in Indonesia: a randomized trial.

Maternal caregiving capacity, which is affected in part by cognition and mood, is crucial for the health of mothers and infants. Few interventions aim to improve maternal and infant health through improving such capacity. Multiple micronutrient (MMN) supplementation may improve maternal cognition and mood, since micronutrients are essential for brain function. We assessed mothers who participated in the Supplementation with Multiple Micronutrients Intervention Trial (SUMMIT), a double-blind cluster-randomized trial in Indonesia comparing MMN supplementation to iron and folic acid (IFA) during pregnancy and until three months postpartum. We adapted a set of well-studied tests of cognition, motor dexterity, and mood to the local context and administered them to a random sample of 640 SUMMIT participants after an average of 25 weeks (SD = 9) of supplementation. Analysis was by intention to treat. Controlling for maternal age, education, and socio-economic status, MMN resulted in a benefit of 0.12 SD on overall cognition, compared to IFA (95%CI 0.03-0.22, p = .010), and a benefit of 0.18 SD on reading efficiency (95%CI 0.02-0.35, p = .031). Both effects were found particularly in anemic (hemoglobin<110 g/L; overall cognition: B = 0.20, 0.00-0.41, p = .055; reading: B = 0.40, 0.02-0.77, p = .039) and undernourished (mid-upper arm circumference<23.5 cm; overall cognition: B = 0.33, 0.07-0.59, p = .020; reading: B = 0.65, 0.19-1.12, p = .007) mothers. The benefit of MMN on overall cognition was equivalent to the benefit of one year of education for all mothers, to two years of education for anemic mothers, and to three years of education for undernourished mothers. No effects were found on maternal motor dexterity or mood. This is the first study demonstrating an improvement in maternal cognition with MMN supplementation. This improvement may increase the quality of care mothers provide for their infants, potentially partly mediating effects of maternal MMN supplementation on infant health and survival. The study is registered as an International Standard Randomized Controlled Trial, number ISRCTN34151616. http://www.controlled-trials.com/ISRCTN34151616.

Impact of the aqueous extract of Eclipta alba on maternal aggression in rats.

Parturient females display impulsive behavior represented in the form of aggressive bouts when exposed to conspecifics. Prolonged aggression during the postpartum period could affect maternal care. Eclipta alba is traditionally known to induce neuropsychiatric alterations, however its ability to circumvent maternal aggression has not been elucidated. The present study was aimed to investigate the ability of the aqueous extract of Eclipta alba to suppress maternal aggression. In the single dose study, 100, 200 and 500 mg/kg body weight of the aqueous extract of Eclipta alba was administered to parturient females 30 minutes prior to maternal aggression testing against intruder males. In the multiple dose study, 100, 200 and 500 mg/kg of the extract were administered for 15 and 30 days and maternal aggression was quantified. Administration of the extract for 15 and 30 days in dose schedules of 200 and 500 mg/kg body weight significantly suppressed agonistic encounters by the dams and therefore had beneficial anti-aggressive activity.

Effects of genistein in the maternal diet on reproductive development and spatial learning in male rats.

Endocrine disruptors, chemicals that disturb the actions of endogenous hormones, have been implicated in birth defects associated with hormone-dependent development. Phytoestrogens are a class of endocrine disruptors found in plants. In the current study we examined the effects of exposure at various perinatal time periods to genistein, a soy phytoestrogen, on reproductive development and learning in male rats. Dams were fed genistein-containing (5 mg/kg feed) food during both gestation and lactation, during gestation only, during lactation only, or during neither period. Measures of reproductive development and body mass were taken in the male offspring during postnatal development, and learning and memory performance was assessed in adulthood. Genistein exposure via the maternal diet decreased body mass in the male offspring of dams fed genistein during both gestation and lactation, during lactation only, but not during gestation only. Genistein decreased anogenital distance when exposure was during both gestation and lactation, but there was no effect when exposure was limited to one of these time periods. Similarly, spatial learning in the Morris water maze was impaired in male rats exposed to genistein during both gestation and lactation, but not in rats exposed during only one of these time periods. There was no effect of genistein on cued or contextual fear conditioning. In summary, the data indicate that exposure to genistein through the maternal diet significantly impacts growth in male offspring if exposure is during lactation. The effects of genistein on reproductive development and spatial learning required exposure throughout the pre- and postnatal periods.

The neuropsychopharmacological effects of Catha edulis in mice offspring born to mothers exposed during pregnancy and lactation.

Chewing fresh leaves of the khat plant (Catha edulis Forsk) is a deep rooted and widespread habit in East Africa and the Middle East. Although a body of knowledge exists about the adverse effects of khat during pregnancy, data are sparse with regard to the consequences of long-term exposure during pregnancy and lactation. The present work, therefore, was initiated to evaluate the neuropsychopharmacological effects of Catha edulis exposure during pregnancy and lactation in mice at postnatal day 28. To this effect, a lyophilized extract of khat (100 mg/kg, K100 and 200 mg/kg, K200), amphetamine (1 mg/kg, positive control, AMP), and a similar volume of 2% v/v Tween-80 in distilled water (negative control, CONT) were administered daily to pregnant mice from gestational day 6 until weaning. Neuropsychopharmacological measurements were done by making use of a battery of neurobehavioural and cognitive tests. Moreover, toxicity to liver and kidney was also evaluated by determining biochemical markers for possible tissue damage. K200 produced significant motor in-coordination and emotional instability; as revealed by impairment in both cliff avoidance (p < 0.01) and forelimb grip strength (p < 0.001), as well as by an increase in stereotyped behaviour such as grooming (p < 0.05), and in the percent of time spent in open arms (p < 0.05). On the other hand, K100 had an effect only on grip strength where a decrement was noted (p < 0.01). A different pattern emerged with AMP whilst it increased duration of sniffing (p < 0.05), neither grip strength nor the time spent in the open arm was affected compared with CONT. Increased latency to reach the goal box and the number of wrong decisions (p < 0.05) in both the learning and the recall tests was observed with K200 and AMP. By contrast, both doses of khat and AMP equally affected performance in the Y-maze (p < 0.05). Alterations in the biochemical indices of liver and kidney function were also noted with AMP and K200. These findings indicate that khat exposure produces dose-related central and peripheral effects during pregnancy and lactation which might pose a serious impediment to the physical and mental development of the offspring.

Neurobehavioral effects of sodium tungstate exposure on rats and their progeny.

The use of tungsten as a replacement for lead and depleted uranium in munitions began in the mid 1990's. Recent reports demonstrate tungsten solubilizes in soil and can migrate into drinking water supplies and therefore is a potential health risk to humans. This study evaluated the reproductive and neurobehavioral effects of sodium tungstate in Sprague-Dawley rats following 70 days of daily pre- and postnatal exposure. Adult male and female rats were orally dosed with diH(2)O vehicle, 5 or 125 mg/kg/day of sodium tungstate through mating, gestation, and weaning (PND 0-20). Daily administration of sodium tungstate produced no overt evidence of toxicity and had no apparent effect on mating success or offspring physical development. Distress vocalizations were elevated in the highest dose group. There was no treatment related effect on righting reflex latencies, however, the males had significantly shorter latencies than the females. Locomotor activity was affected in both the low and high dose groups of F0 females. Those in the low dose group showed increased distance traveled, more time in ambulatory movements, and less time in stereotypic behavior than controls or high dose animals. The high dose group had more time in stereotypical movements than controls, and less time resting than controls and the lowest exposure group. Maternal retrieval was not affected by sodium tungstate exposure and there were no apparent effects of treatment on F1 acoustic startle response or water maze navigation. Overall, the results of this study suggest pre- and postnatal oral exposure to sodium tungstate may produce subtle neurobehavioral effects in offspring related to motor activity and emotionality. These findings warrant further investigation to characterize the neurotoxicity of sodium tungstate on dams and their developing pups.

Oxytocin and the maternal brain.

Oxytocin released within the brain from both magnocellular and parvocellular systems of the hypothalamus has diverse effects on behavior. When oxytocin is released within the brain, its effects are to diminish fearfulness; this not only encourages social investigation of newcomers, but also may enhance a tendency to express aggression toward an intruder. Oxytocin supports social recognition, redirects behavior away from feeding directed behavior toward sexual behavior, and facilitates the formation of social bonds. This system, which depends not only upon release of oxytocin but also on oxytocin receptor distribution within the brain, becomes particularly important at parturition, when a bond is first formed between mother and offspring.

Effects of diets enriched in omega-3 and omega-6 polyunsaturated fatty acids on offspring sex-ratio and maternal behavior in mice.

There have been many trials describing the effects of polyunsaturated fatty acids (PUFA) on fecundity, neonatal development, and maternal behavior in humans, but few controlled studies in rodents. We examined the effects of a maternal diet high in omega 3 (N-3) or omega 6 (N-6) PUFA on NIH Swiss mice. Female mice were ad libitum fed one of three complete and balanced diets (N-3, enriched in menhaden oil; N-6, enriched in corn oil; C, control diet, Purina 5015) from age 4 wk until the end of the study. Mice were bred at approximately 19 wk and 27 wk of age, providing a total of 838 pups from 129 litters in two experiments. After weaning their pups from parity 1, behavior of dams was assessed on elevated-plus and open-field mazes. Although the fraction of male pups from the N-3 and C groups was not different from 0.5, dams on the N-6 diet birthed more daughters than sons (213 vs. 133; P < 0.001). Although maternal stress has been reported to favor birth of daughters, the behavior of N-6 dams was not different from controls. By contrast, the N-3 dams displayed greater anxiety, spending less time in the open arms and more time in the closed arms of the elevated maze and traveling less distance and exhibiting less exploratory behavior in the open field (P < 0.05). N-3 dams tended to produce smaller litters than C dams, and N-3-suckled pups gained less weight (P < 0.05). In conclusion, the N-3 diet had negative effects on murine fecundity and maternal behavior, whereas the N-6 diet favored birth of daughters.

Epigenetic programming by maternal behavior and pharmacological intervention. Nature versus nurture: let's call the whole thing off.

The nature of maternal care that an infant receives can effect the child's emotional and cognitive development, which is endured into adulthood. Similarly, maternal behavior in rodents is associated with long-term programming of individual differences in behavioral and hypothalamic-pituitary-adrenal responses to stress in the offspring. One critical question is how is such 'environmental programming' established and sustained in the offspring? This review discusses a novel mechanism to explain how maternal licking/grooming behavior in the rat can alter the hippocampal glucocorticoid receptor (GR) expression in the offspring, which concomitantly alters the HPA axis and the stress responsiveness of these animals. Both in vivo and in vitro studies show that maternal behavior increases GR expression in the offspring via increased hippocampal serotonergic tone accompanied by increased histone acetylase transferase activity, histone acetylation and DNA demethylation mediated by the transcription factor NGFI-A. In summary, this research demonstrates that an epigenetic state of a gene can be established through early-in-life experience, and is potentially reversible in adulthood. Accordingly, epigenetic modifications of specific genomic regions in response to variations in environmental conditions might serve as a major source of variation in biological and behavioral phenotypes.