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Maternal Deprivation (maternal + deprivation)

Distribution by Scientific Domains

Medical Sciences	45%

Selected Abstracts

Differential and Age-Dependent Effects of Maternal Deprivation on the Hypothalamic-Pituitary-Adrenal Axis of Brown Norway Rats from Youth to Senescence

JOURNAL OF NEUROENDOCRINOLOGY, Issue 7 2001
J. O. Workel
Abstract In this study, the hypothesis was tested that infants deprived from maternal care show persistent changes in hypothalamic-pituitary-adrenal activity. For this purpose, we studied the effect of maternal deprivation in one cohort of the healthy ageing Brown Norway rat strain showing still more than 80% survival rate at 32 months of age. Three-day-old male Brown Norway rats were either maternally deprived for 24 h or remained with the dam. In 3, 12 and 30,32 months (young, adult, senescent) deprived rats and their nondeprived littermates (controls), we determined basal resting and stress-induced plasma adrenocorticotropic hormone (ACTH) and corticosterone as well as corticotropin releasing hormone (CRH) mRNA expression in the paraventricular nucleus (PVN) of the hypothalamus. Mineralocorticoid (MR) and glucocorticoid receptors (GR) in hippocampus and PVN were also assessed using in vitro cytosol binding and in situ hybridization. The effect of ageing per se showed that in the control nondeprived Brown Norway rats, basal corticosterone and ACTH concentrations did not change during life. However, with age, the corticosterone response to novelty stress became progressively attenuated, but prolonged, while there was an age-related increase in the ACTH response. CRH mRNA expression in PVN decreased with age. Hippocampal MR binding and MR mRNA expression in the dentate gyrus were reduced at senescence, as were the GR binding capacities in hippocampus and hypothalamus. Maternal deprivation did not affect survival rate, body weight, nor adrenal weight of the ageing Brown Norway rats. Basal corticosterone and ACTH levels were not affected by deprivation, except for a rise in basal corticosterone concentrations at 3 months. At this age, the corticosterone output in response to novelty was attenuated in the deprived rats. In contrast, a striking surge in novelty stress-induced corticosterone output occurred at midlife while, at senescence, the corticosterone and ACTH responses were attenuated again in the deprived animals, particularly after the more severe restraint stressor. CRH mRNA expression was reduced only during adulthood in the deprived animals. After maternal deprivation, the MR mRNA in dentate gyrus showed a transient midlife rise. GR binding in hypothalamus and hippocampus GR binding was reduced in young rats while, in the senescent deprived animals, a reduced GRmRNA expression was observed in PVN and hippocampal CA1. In conclusion, in the Brown Norway rat, ageing causes a progressive decline in corticosterone output after stress, which is paralleled at senescence by decreased MR and GR mRNA expression in hippocampus and hypothalamus. The long-term effects of maternal deprivation become manifest differently at different ages and depend on test conditions. The deprivation effect culminates in a midlife corticosterone surge and results at senescence in a strongly reduced corticosterone output. [source]

Motherless rats show deficits in maternal behavior towards fostered pups

DEVELOPMENTAL PSYCHOBIOLOGY, Issue 2 2010
Daniela J. Palombo
Abstract Complete maternal deprivation in rats, through artificial rearing (AR), produces deficits in subsequent maternal behavior of the offspring. These deficits are partially reversed when isolated pups are provided with additional tactile stimulation designed to simulate maternal licking (e.g., Gonzalez et al. [2001] Developmental Psychobiology, 38, 11,32). These findings highlight the importance of the early maternal environment in subsequent development. However, given the possibility that prenatal environments may differ between AR and maternally reared (MR) offspring, the deficits in the behavior of AR mothers may be driven by the characteristics of their pups derived from the effects of an altered prenatal environment. Hence differences in the neonatal pups of AR mothers may produce the alterations in the AR maternal behavior. To rule out this possibility, we employed a fostering paradigm where AR and MR mothers received cross-fostered mother-reared pups. AR mothers showed the same level of deficits in maternal behavior towards MR foster pups as they do with their own pups and these deficits were partially reversed with additional tactile stimulation. Hence, maternal behavior deficits reported in mothers who had been reared in isolation are due primarily to the direct effects of the earlier experience on mechanisms regulating their maternal behavior and not to the effects on their offspring. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 52:142,148, 2010 [source]

Rapid acquisition of operant conditioning in 5-day-old rat pups: A new technique articulating suckling-related motor activity and milk reinforcement

DEVELOPMENTAL PSYCHOBIOLOGY, Issue 6 2007
Carlos Arias
Abstract Newborn rats are capable of obtaining milk by attaching to a surrogate nipple. During this procedure pups show a gradual increase in head and forelimb movements oriented towards the artificial device that are similar to those observed during nipple attachment. In the present study the probability of execution of these behaviors was analyzed as a function of their contingency with intraoral milk infusion using brief training procedures (15 min). Five-day-old pups were positioned in a smooth surface having access to a touch-sensitive sensor. Physical contact with the sensor activated an infusion pump which served to deliver intraoral milk reinforcement (Paired group). Yoked controls received the reinforcer when Paired neonates touched the sensor. Paired pups trained under a continuous reinforcement schedule emitted significantly more responses than Yoked controls following two (Experiment 1) or one training session (Experiment 2). These differences were also observed during an extinction session conducted immediately after training. The level of maternal deprivation before training (3 or 6 hr) or the volume of milk delivered (1.0 or 1.5 µl per pulse) did not affect acquisition or extinction performances. In addition, it was observed that the rate of responding of Paired pups during the early phase of the extinction session significantly predicted subsequent levels of acceptance of the reinforcer. These results indicate that the frequency of suckling-related behaviors can be rapidly modified by means of associative operant processes. The operant procedure here described represents an alternative tool for the ontogenetic analysis of self-administration or behavior processes of seeking. © 2007 Wiley Periodicals, Inc. Dev Psychobiol 49: 576-588, 2007. [source]

Complete maternal deprivation affects social, but not spatial, learning in adult rats

DEVELOPMENTAL PSYCHOBIOLOGY, Issue 3 2003
F. Lévy
Abstract The effects of maternal deprivation on learning of social and spatial tasks were investigated in female adult rats. Pups were reared artificially and received "lickinglike" tactile stimulation (AR animals) or were reared with their mothers (MR animals). In adulthood, subjects were tested on paradigms of spatial learning and on paradigms involving learning of social cues. Results showed that maternal deprivation did not affect performance on spatial learning, but it did impair performance on the three social learning tasks. The AR animals made no distinction between a new and a previously presented juvenile conspecific. AR animals also responded less rapidly than MR animals at test for maternal behavior 2 weeks after a postpartum experience with pups. Finally, AR animals did not develop a preference for a food previously eaten by a familiar conspecific whereas MR animals did. This study indicates that animals reared without mother and siblings show no deficits in spatial tasks while showing consistent deficits in learning involving social interactions. © 2003 Wiley Periodicals, Inc. Dev Psychobiol 43: 177,191, 2003. [source]

Touch attenuates infants' physiological reactivity to stress

DEVELOPMENTAL SCIENCE, Issue 2 2010
Ruth Feldman
Animal studies demonstrate that maternal touch and contact regulate infant stress, and handling during periods of maternal deprivation attenuates the stress response. To measure the effects of touch on infant stress reactivity during simulated maternal deprivation, 53 dyads were tested in two paradigms: still-face (SF) and still-face with maternal touch (SF+T). Maternal and infant cortisol levels were sampled at baseline, reactivity, and recovery and mother's and infant's cardiac vagal tone were measured during the free play, still-face, and reunion episodes of the procedure. Cortisol reactivity was higher among infants in the SF condition and while cortisol decreased at recovery for infants in the SF+T, it further increased for those in the SF. Vagal tone showed a greater suppression when SF was not accompanied by maternal touch. Touch synchrony during free play was associated with higher infant vagal tone, whereas touch myssynchrony , maternal tactile stimulation while the infant gaze averts , correlated with higher maternal and infant cortisol. In humans, as in mammals, the provision of touch during moments of maternal unavailability reduces infants' physiological reactivity to stress. [source]

Environmental manipulations early in development alter seizure activity, Ih and HCN1 protein expression later in life

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 12 2006
Ulrich Schridde
Abstract Although absence epilepsy has a genetic origin, evidence from an animal model (Wistar Albino Glaxo/Rijswijk; WAG/Rij) suggests that seizures are sensitive to environmental manipulations. Here, we show that manipulations of the early rearing environment (neonatal handling, maternal deprivation) of WAG/Rij rats leads to a pronounced decrease in seizure activity later in life. Recent observations link seizure activity in WAG/Rij rats to the hyperpolarization-activated cation current (Ih) in the somatosensory cortex, the site of seizure generation. Therefore, we investigated whether the alterations in seizure activity between rats reared differently might be correlated with changes in Ih and its channel subunits hyperpolarization-activated cation channel HCN1, 2 and 4. Whole-cell recordings from layer 5 pyramidal neurons, in situ hybridization and Western blot of the somatosensory cortex revealed an increase in Ih and HCN1 in neonatal handled and maternal deprived, compared to control rats. The increase was specific to HCN1 protein expression and did not involve HCN2/4 protein expression, or mRNA expression of any of the subunits (HCN1, 2, 4). Our findings provide the first evidence that relatively mild changes in the neonatal environment have a long-term impact of absence seizures, Ih and HCN1, and suggest that an increase of Ih and HCN1 is associated with absence seizure reduction. Our findings shed new light on the role of Ih and HCN in brain functioning and development and demonstrate that genetically determined absence seizures are quite sensitive for early interventions. [source]

Differential and Age-Dependent Effects of Maternal Deprivation on the Hypothalamic-Pituitary-Adrenal Axis of Brown Norway Rats from Youth to Senescence

The effect of ,two hit' neonatal and young-adult stress on dopaminergic modulation of prepulse inhibition and dopamine receptor density

BRITISH JOURNAL OF PHARMACOLOGY, Issue 2 2009
Kwok Ho Christopher Choy
Background and purpose:, A combination of early neurodevelopmental insult(s) and young-adult stress exposure may be involved in the development of schizophrenia. We studied prepulse inhibition (PPI) regulation in rats after an early stress, maternal deprivation, combined with a later stress, simulated by chronic corticosterone treatment, and also determined whether changes in brain dopamine receptor density were involved. Experimental approach:, Rats were subjected to either 24 h maternal deprivation on postnatal day 9, corticosterone treatment from 8 to 10 weeks of age, or both. At 12 weeks of age, the rats were injected with 0.1, 0.3 or 1.0 mg·kg,1 of apomorphine or 0.5 or 2.5 mg·kg,1 of amphetamine and PPI was determined using automated startle boxes. Dopamine D1 and D2 receptor levels were assessed in the nucleus accumbens and caudate nucleus using receptor autoradiography. Key results:, Young-adult treatment with corticosterone resulted in attenuated disruption of PPI by apomorphine and amphetamine. In some rats, maternal deprivation resulted in reduced baseline PPI which added to the effect of corticosterone treatment. There was no down-regulation of dopamine D1 or D2 receptors. Conclusions and implications:, These results confirm and extend our finding of an inhibitory interaction of developmental stress on dopaminergic regulation of PPI. No corresponding changes in dopamine receptor density were observed in brain regions with a major involvement in PPI regulation, suggesting long-lasting desensitization of dopamine receptor signalling or indirect changes in PPI regulation. [source]