Weeks Of Postnatal Life Research Articles

Reactive astrogliosis causes the development of spontaneous seizures.

Epilepsy is one of the most common chronic neurologic diseases, yet approximately one-third of affected patients do not respond to anticonvulsive drugs that target neurons or neuronal circuits. Reactive astrocytes are commonly found in putative epileptic foci and have been hypothesized to be disease contributors because they lose essential homeostatic capabilities. However, since brain pathology induces astrocytes to become reactive, it is difficult to distinguish whether astrogliosis is a cause or a consequence of epileptogenesis. We now present a mouse model of genetically induced, widespread chronic astrogliosis after conditional deletion of β1-integrin (Itgβ1). In these mice, astrogliosis occurs in the absence of other pathologies and without BBB breach or significant inflammation. Electroencephalography with simultaneous video recording revealed that these mice develop spontaneous seizures during the first six postnatal weeks of life and brain slices show neuronal hyperexcitability. This was not observed in mice with neuronal-targeted β1-integrin deletion, supporting the hypothesis that astrogliosis is sufficient to induce epileptic seizures. Whole-cell patch-clamp recordings from astrocytes further suggest that the heightened excitability was associated with impaired astrocytic glutamate uptake. Moreover, the relative expression of the cation-chloride cotransporters (CCC) NKCC1 (Slc12a2) and KCC2 (Slc12a5), which are responsible for establishing the neuronal Cl(-) gradient that governs GABAergic inhibition were altered and the NKCC1 inhibitor bumetanide eliminated seizures in a subgroup of mice. These data suggest that a shift in the relative expression of neuronal NKCC1 and KCC2, similar to that observed in immature neurons during development, may contribute to astrogliosis-associated seizures.

The incubator psyche

This paper considers the emotional life of the infant in the incubator and develops a new psychological theory which is called the ‘incubator psyche’. Theory building is advanced from three main discourses: (1) psychoanalysis, (2) neo-natal nursing and (3) psychology. A case study of Corey, a 7-year-old boy, who had been delivered prematurely, with a hole in his heart, and spent the first 6 weeks of post-natal life in an incubator, is presented to illustrate how aspects of an incubator psyche might be clinically manifest. The concept of an incubator psyche is advanced with reference to a particular kind of second-skin formation (Bick, 1968, The experience of the skin in early object relations, The International Journal of Psychoanalysis, 49, 484–486). It is proposed that the incubator psyche characterises a client's mental functioning exercised as an environmental sensibility that could be understood in terms of the total transference situation (Klein, 1952, The origins of transference, International Journal of Psychoanalysis, 33, 433–438; Joseph, 1985, Transference: The total situation, International Journal of Psychoanalysis, 66, 447–454). Implications for practice are considered advocating particular attention to the setting.

Brain Transcriptome Database (BrainTx, formerly CDT-DB) � Profiling of spatio-temporal gene expression during postnatal development of mouse brain

Brain Transcriptome Database (BrainTx, formerly CDT-DB) � Profiling of spatio-temporal gene expression during postnatal development of mouse brain

Clonidine treatment delays postnatal motor development and blocks short-term memory in young mice.

During the development of the nervous system, the perinatal period is particularly sensitive as neuronal connections are still forming in the brain of the neonate. Alpha2-adrenergic receptors are overexpressed temporarily in proliferative zones in the developing brain, reaching a peak during the first postnatal week of life. Both stimulation and blocking of these receptors during this period alter the development of neural circuits, affecting synaptic connectivity and neuronal responses. They even affect motor and cognitive skills later on in the adult. It's especially important to look for the early neurological consequences resulting from such modifications, because they may go unnoticed. The main objective of the present study has been to reaffirm the importance of the maturation of alpha-adrenergic system in mice, by carrying out a comprehensive examination of motor, behavioral and cognitive effects in neonates, during early postnatal development, following chronic administration of the drug Clonidine, an alpha2 adrenergic system agonist. Our study shows that mice treated postnatally with clonidine present a temporal delay in the appearance of developmental markers, a slow execution of vestibular reflexes during first postnatal week of life and a blockade of the short term memory in the novel object recognition task. Shortly after the treatment the startle response is hyperreactive.

Ethanol-induced tolerance and sex-dependent sensitization in preweanling rats

According to genetic studies, the acute stimulating effect of ethanol seems to be associated with an increased predisposition to consume large quantities of ethanol. Ethanol-induced stimulation has been rarely reported in adult rats. However, infant rats, particularly during the second postnatal week of life, are highly sensitive to ethanol-induced behavioral activation. They also consume more ethanol than in later ontogenetic stages. In adult mice repeated ethanol experience usually results in sensitization to the stimulating effect of ethanol, while tolerance is the predominant result in rats. The present study was designed to explore in rats whether repeated exposure to ethanol during infancy modifies subjects' sensitivity to the stimulating effect of the drug, either increasing or decreasing its magnitude (i.e. sensitization or tolerance, respectively). Furthermore, we also explored the possible context-modulation of these effects. In two experiments, subjects were trained with water or ethanol (2.5g/kg) between postnatal days (PDs) 8 and 12 (Experiment 1) or between PDs 14 and 18 (Experiment 2), and tested in response to water or ethanol two days later. In these experiments we identified three variables that critically modulate the effect of the repeated ethanol exposure: sex, context and age. Ethanol exclusively and consistently induced locomotor sensitization in males trained outside of the testing context (Experiments 1a and 1b), while tolerance to the stimulating effect of ethanol was observed in males and females trained in the testing context (Experiment 1a). In Experiment 2 tolerance was detected in females trained outside of the testing context. Finally, experience with the testing context during training strongly attenuated the stimulating effect of ethanol in the older subjects (Experiment 2). These results show that the same ethanol treatment can produce opposite effects (tolerance or sensitization) and demonstrate the involvement of Pavlovian conditioning in the development of tolerance. Furthermore, sex was revealed as an important factor to take into consideration in the analysis of chronic experience with ethanol during infancy. We can conclude that specific ontogenetic stages can be used to study the biological determinants underlying both ethanol-induced tolerance and sensitization, and the environmental modulators of these effects.

Neonatal overnutrition causes early alterations in the central response to peripheral ghrelin.

ObjectiveExcess nutrient supply and rapid weight gain during early life are risk factors for the development of obesity during adulthood. This metabolic malprogramming may be mediated by endocrine disturbances during critical periods of development. Ghrelin is a metabolic hormone secreted from the stomach that acts centrally to promote feeding behavior by binding to growth hormone secretagogue receptors in the arcuate nucleus of the hypothalamus. Here, we examined whether neonatal overnutrition causes changes in the ghrelin system.MethodsWe used a well-described mouse model of divergent litter sizes to study the effects of postnatal overfeeding on the central and peripheral ghrelin systems during postnatal development.ResultsMice raised in small litters became overweight during lactation and remained overweight with increased adiposity as adults. Neonatally overnourished mice showed attenuated levels of total and acyl ghrelin in serum and decreased levels of Ghrelin mRNA expression in the stomach during the third week of postnatal life. Normalization of hypoghrelinemia in overnourished pups was relatively ineffective at ameliorating metabolic outcomes, suggesting that small litter pups may present ghrelin resistance. Consistent with this idea, neonatally overnourished pups displayed an impaired central response to peripheral ghrelin. The mechanisms underlying this ghrelin resistance appear to include diminished ghrelin transport into the hypothalamus.ConclusionsEarly postnatal overnutrition results in central resistance to peripheral ghrelin during important periods of hypothalamic development. Because ghrelin signaling has recently been implicated in the neonatal programming of metabolism, these alterations in the ghrelin system may contribute to the metabolic defects observed in postnatally overnourished mice.

Effect of repeated alcohol exposure during the third trimester-equivalent on messenger RNA levels for interleukin-1β, chemokine (C–C motif) ligand 2, and interleukin 10 in the developing rat brain after injection of lipopolysaccharide

Microglia undergo maturation during the third trimester of human development (equivalent to the first 1–2 weeks of postnatal life in rodents), during which these cells may be particularly sensitive to insult. Alcohol exposure during this period can activate the neuroimmune system, an effect that may contribute to the pathophysiology of fetal alcohol spectrum disorders. Here, we investigated whether repeated alcohol exposure during the third trimester-equivalent in rats has a priming effect on the neuroimmune response to injection of bacterial lipopolysaccharide (LPS). Pups were exposed to alcohol in vapor chambers for 4 h daily from postnatal day (PD)2 to PD16 (peak blood alcohol concentrations ∼150 mg/dL). On PD17, rats were injected with either saline or LPS (50 μg/kg) and the frontal cortex, cerebellar vermis, and dentate gyrus were collected 2 h later. Messenger RNA (mRNA) levels for the pro-inflammatory agents interleukin 1β (IL-1β) and chemokine (C–C) motif ligand 2 (CCL2), as well as levels of the anti-inflammatory cytokine interleukin 10 (IL-10), were measured using reverse transcriptase polymerase chain reaction. LPS consistently increased IL-1β and CCL2 mRNA levels in the dentate gyrus, frontal cortex, and cerebellum of both male and female rats. Furthermore, the LPS-induced increase of IL-1β mRNA levels was significantly blunted in the frontal cortex of alcohol-exposed female rats. Conversely, LPS only minimally affected IL-10 mRNA expression and there were no significant differences between air- and alcohol-exposed rats. Taken together with the literature regarding the effect of third-trimester alcohol exposure on the neuroimmune system, our findings suggest that chronic exposure to lower levels is less disruptive to the neuroimmune system than binge-like exposure to high doses of alcohol.

Moderate Alcohol Exposure during the Rat Equivalent to the Third Trimester of Human Pregnancy Alters Regulation of GABAA Receptor-Mediated Synaptic Transmission by Dopamine in the Basolateral Amygdala

Fetal ethanol (EtOH) exposure leads to a range of neurobehavioral alterations, including deficits in emotional processing. The basolateral amygdala (BLA) plays a critical role in modulating emotional processing, in part, via dopamine (DA) regulation of GABA transmission. This BLA modulatory system is acquired during the first 2 weeks of postnatal life in rodents (equivalent to the third trimester of human pregnancy) and we hypothesized that it could be altered by EtOH exposure during this period. We found that exposure of rats to moderate levels of EtOH vapor during the third trimester-equivalent [postnatal days (P) 2–12] alters DA modulation of GABAergic transmission in BLA pyramidal neurons during periadolescence. Specifically, D1R-mediated potentiation of spontaneous inhibitory postsynaptic currents (IPSCs) was significantly attenuated in EtOH-exposed animals. However, this was associated with a compensatory decrease in D3R-mediated suppression of miniature IPSCs. Western blot analysis revealed that these effects were not a result of altered D1R or D3R levels. BLA samples from EtOH-exposed animals also had significantly lower levels of the DA precursor (L-3,4-dihydroxyphenylalanine) but DA levels were not affected. This is likely a consequence of reduced catabolism of DA, as indicated by reduced levels of 3,4-dihydroxyphenylacetic acid and homovanillic acid in the BLA samples. Anxiety-like behavior was not altered in EtOH-exposed animals. This is the first study to demonstrate that the modulatory actions of DA in the BLA are altered by developmental EtOH exposure. Although compensatory adaptations were engaged in our moderate EtOH exposure paradigm, it is possible that these are not able to restore homeostasis and correct anxiety-like behaviors under conditions of heavier EtOH exposure. Therefore, future studies should investigate the potential role of alterations in the modulatory actions of DA in the pathophysiology of fetal alcohol spectrum disorders.

Minocycline prevents the attenuated acute hypoxic ventilatory response and changes in brainstem neurochemistry following neonatal sustained hypoxia exposure (1092.11)

Sustained hypoxia (SH) exposure uniquely during the end of the second postnatal week of life (postnatal (P) age 11‐15) attenuates the acute hypoxic ventilatory response (HVR) in rats. In the current study, we investigated whether the microglia inhibitor minocycline would be protective against the SH‐induced attenuation of the HVR and changes in brainstem neurochemistry. Neonatal rats were exposed to SH (11% O2, 5 days) starting at P11 and received an i.p. injection of minocycline (25mg/kg) or saline midway into the exposure period; plethysmography and measurements of brainstem immunoreactivity for Iba1 and 5‐HT were performed the day after SH ended (P16). SH exposure attenuated the HVR, increased Iba1 and decreased 5‐HT immunoreactivity in the nTS compared normoxia raised rats. Minocycline prevented the SH‐induced attenuated HVR including the changes in nTS Iba1 and 5‐HT immunoreactivity. We speculate that brainstem microglia may be involved in SH‐induced changes in brainstem neurochemistry leading to a 5‐HT‐induced modification of the mechanisms mediating the acute HVR. These data share several similarities to Sudden Infant Death Syndrome victims including evidence of impaired (cardio)‐respiratory control, brainstem gliosis, and serotonergic deficits associated with a vulnerability to an environmental stressor.

Brief neonatal handling alters sexually dimorphic behaviors in adult rats.

Several effects of neonatal handling on brain and behavior have been reported. We investigated the effects of neonatal handling on behaviors that have been shown to be sexually dimorphic in rats using an open-field test. "Gender differences" were observed in locomotor activity, exploratory behavior and grooming in the handled group. However, clear gender differences in these behaviors were not observed in the non-handled group. Our findings show that brief daily handling sessions (~ 1 min) in the first 2 weeks of postnatal life increased locomotor activity and exploratory behavior, and that these effects were more pronounced in females. Moreover, many rats in the non-handling group exhibited an increase in defecation relative to the handling group during the 10-min observation period. This suggests that the non-handling group experienced more stress in response to the novel open-field arena, and that this resulted in the absence of gender differences. Notably, this anxiety-related response was attenuated by neonatal handling. Our study underscores the impact of brief neonatal handling on sexually dimorphic behaviors, and indicates that caution should be exercised in controlling for the effects of handling between experimental groups, particularly in neurotoxicological studies that evaluate gender differences.

GSK3β regulates oligodendrogenesis in the dorsal microdomain of the subventricular zone via Wnt-β-catenin signaling

Oligodendrocytes, the myelinating cells of the CNS, are derived postnatally from oligodendrocyte precursors (OPs) of the subventricular zone (SVZ). However, the mechanisms that regulate their generation from SVZ neural stem cells (NSC) are poorly understood. Here, we have examined the role of glycogen synthase kinase 3β (GSK3β), an effector of multiple converging signaling pathways in postnatal mice. The expression of GSK3β by rt-qPCR was most prominent in the SVZ and in the developing white matter, around the first 1–2 weeks of postnatal life, coinciding with the peak periods of OP differentiation. Intraventricular infusion of the GSK3β inhibitor ARA-014418 in mice aged postnatal day (P) 8–11 significantly increased generation of OPs in the dorsal microdomain of the SVZ, as shown by expression of cell specific markers using rt-qPCR and immunolabelling. Analysis of stage specific markers revealed that the augmentation of OPs occurred via increased specification from earlier SVZ cell types. These effects of GSK3β inhibition on the dorsal SVZ were largely attributable to stimulation of the canonical Wnt/β-catenin signaling pathway over other pathways. The results indicate GSK3β is a key endogenous factor for specifically regulating oligodendrogenesis from the dorsal SVZ microdomain under the control of Wnt-signaling.

Long-Term Impact of Maternal Protein Malnutrition on Learning and Memory Abilities and DNA Methylating Profiles of the Nervous System in Offspring Rats

Objective: To determine the mechanisms by which protein deficiency during pregnancy can lead to long-term alterations in learning and memory abilities of the offspring in rats. Study design: Fourty-two pregnant rats were fed control (n = 23) or low protein (n = 19) diets ad libitum until parturition. On the 8th week of post-natal life which represented early adulthood, eighty-four offsprings (control group: n = 52, LP group: n = 32) were determined their learning & memory ability by using the Morris water maze test. Six offprings’ brain tissue (control group: n = 3, LP group: n = 3) was also analysed for DNA methylating profiles, the GO and KEGG pathways, methylation status and twelve for protein expression (control group: n = 6, LP group: n = 6). Results: The offsprings of the protein-deficient-diet fed rats learnt faster initially then lagged behind those of the control rats, especially in female rats (p = 0.035). There were a series of genes methylated in the CpG island and pormoter area. Quantitative Mass Array data showed methylation differences in Grin2b and Grin2b_3CpG 3, 4, & 5 might be the target sites as shown by dual-luciferase assay. A decreased level of protein expression of NMDAR2B was observed. Conclusion: Differential methylation status in Grin2b and changes in expression of NMDAR2B may partially explain the long-term impact of maternal protein deficiency on the cognitive and learning capabilities of offsprings.

Neonatal brainstem dysfunction after preterm birth predicts behavioral inhibition

Behavioral inhibition (BI), the tendency to withdraw or exhibit negative affect when experiencing stressful situations, is a major risk factor for the development of social anxiety. However, neonatal biologic origins of this progression are still unknown. Click here to enter text.This study aimed to extend frameworks of behavioral inhibition by exploring empirically the central role of neonatal brainstem electrophysiologic functions in the development of social disengagement and BI. Sixty-six preterm neonates (means ±SD: gestation age = 33.1 ± 1.22 weeks, birth weight = 1775 + 346.7 g; 51% female) participated in a prospective longitudinal study. The infants were tested within the first 2 weeks of postnatal life using an auditory brainstem-evoked response test. Based on the typicality of the major ABR wave latencies, waves I, III and V, neonates were divided into two groups (compromised, CBSF- with at least one component ≥1.5 SDs from the mean for the respective gestation age; normal, NBSF, with all components within 1.5 SD around the mean), and were enrolled in a prospective longitudinal follow-up study. This report extends previous work from 4 m by testing responses to socioemotional challenges during the Separation-Reunion paradigm at 12 m. Results show that infants with neonatal CBSF were more susceptible to be classified as BI at 12 m (age corrected for prematurity) than infants with NBSF (66% vs. 40%, respectively). The most striking symptom in the CBSF group was a disability to initiate self-regulatory activities in response to a socioemotional challenge, resulting in frequent passivity/dependency (p < .001). Statistical regression analysis revealed that face-to-face gaze engagement at 4 m moderates the risk related to neonatal CBSF for the emergence of BI at 12 m, but did not overturn the emergence of BI. Results support the hypothesis that neonatal brainstem dysfunction canalizes behavioral inhibition. These findings highlight, for the first time, the role of the early developing brainstem in later development of BI and in abilities to initiate self-regulatory behavior.

Perinatal hyperoxic exposure reconfigures the central respiratory network contributing to intolerance to anoxia in newborn rat pups

Perinatal exposure to hyperoxia (30-60% O2) alters the respiratory control system via modulation of peripheral arterial chemoreceptor development and function. Furthermore, hyperoxic exposure during the first two postnatal weeks of life can alternatively modulate the different phases of the hypoxic ventilatory response. Given the effects of perinatal hyperoxia, the aims of our study were 1) to determine the effect on survival time in response to lethal anoxic stimuli in rat pups and 2) to characterize the output of the isolated central respiratory network in response to acute hypoxic stimuli. We hypothesized that perinatal hyperoxic exposure would modify the neonatal rat ventilatory response to anoxia by affecting a central component of the respiratory network in addition to the maturation of the carotid body chemoreceptors. We found that animals continuously exposed to 60% oxygen up to age 5 days after parturition (P5) have reduced breathing frequency at baseline and within the first 10 min of a fatal anoxic challenge. Hyperoxic rat pups also have a shortened time to last gasp in response to anoxia that is not associated with lung injury or inflammation. This study is the first to demonstrate that these in vivo findings correlate with reduced phrenic burst frequency from the isolated brainstem ex vivo. Thus hyperoxic exposure reduced the phrenic burst frequency at baseline and in response to ex vivo anoxia. Importantly, our data suggest that perinatal hyperoxia alters ventilation and the response to anoxia at P5 in part by altering the frequency of phrenic bursts generated by the central respiratory network.

Developmental expression of IL-33 in the mouse brain

IL-33 has important functions in inflammatory and autoimmune diseases. In the brain, models of experimental encephalomyelitis are accompanied by up-regulation of IL-33 expression, and the cytokine is seen as an amplifier of the innate immune response. Little is known, however, about IL-33 the normal brain in adult life, or during development. We have analyzed the expression of IL-33 in the mouse brain during embryonic and postnatal development. Here we report that IL-33 expression was first detected in the CNS during late embryogenesis. From postnatal day 2 (P2) until P9 the expression increased and was strongest in the cerebellum, pons and thalamus, as well as in olfactory bulbs. Expression of IL-33 then became weaker and declined until P23, and it was not present in the adult brain. Both astrocytes and oligodendrocyte precursors expressed IL-33. The vast majority of IL-33 positive cells in the brain displayed nuclear staining, and this was found to be the case also in vitro, using mixed glial cultures. Our data suggest that IL-33 expression is under tight regulation in the normal brain. Its detection during the first three weeks of postnatal life coincides with important parts of the CNS developmental programs, such as general growth and myelination. This opens the possibility that IL-33 plays a role also in the absence of an inflammatory response.

Blood plasma protein and lipid profile changes in calves during the first week of life

The present study was undertaken to determine blood plasma protein and lipid profile changes in healthy Polish Holstein-Fresian calves of Black-and-White variety. Blood was drawn immediately after birth, before first colostrum intake and at the 3rd, 6th, 12th, 24th, 36th, 48th and 72nd hour of life. Subsequent four blood samples were collected at 24 hour intervals until the 7th day of life. Plasma proteins within the isoelectric point ranging from 3.0 to 10.0 were separated using high resolution two-dimensional electrophoresis. Among the 74 protein spots detected and analyzed, 16 were significantly altered during the first week of life. Differentially expressed spots were excised from the gels and subjected to peptide mass fingerprinting using MALDI-TOF MS. In total, 12 spots were successfully identified, which correspond to three proteins, namely: apolipoprotein A-I, apolipoprotein A-IV and fibrinogen gamma-B chain. A gradual increase in plasma triglyceride, total cholesterol, HDL and LDL cholesterol values was shown during the first seven days of calves life. The lowest concentration of these indicators were observed at birth and was followed by a rapid increase during the first week of postnatal life. These changes appear to be related to the transition in energy sources, from a maternal nutrient supply comprising mainly carbohydrates and amino acids to a diet which was rich in fat--colostrum and milk. This was reflected by the intense up-regulation of plasma proteins related with lipid transport and lipoprotein metabolism during the first week of life.

Effects of prenatal exposure to diclofenac sodium and saline on the optic nerve of 4- and 20-week-old male rats: a stereological and histological study

We investigated the effects of diclofenac sodium (DS) on development of the optic nerve in utero. Pregnant female rats were separated into three groups: control, saline treated and DS treated. Offspring of these animals were divided into 4-week-old and 20-week-old groups. At the end of the 4th and 20th weeks of postnatal life, the animals were sacrificed, and right optic nerves were excised and sectioned for ultrastructural and stereological analyses. We demonstrated that both DS and saline produced structural and morphometric changes in the total axon number and density of axons, but decreased the myelin sheath thickness in male optic nerves. All ultrastructural and morphometric features were well developed in 20-week-old rats. We showed that development of the optic nerve continues during the early postnatal period and that some compensation for exposure to deleterious agents in utero may occur during early postnatal life.

β1 integrin is a crucial regulator of pancreatic β-cell expansion

Development of the endocrine compartment of the pancreas, as represented by the islets of Langerhans, occurs through a series of highly regulated events encompassing branching of the pancreatic epithelium, delamination and differentiation of islet progenitors from ductal domains, followed by expansion and three-dimensional organization into islet clusters. Cellular interactions with the extracellular matrix (ECM) mediated by receptors of the integrin family are postulated to regulate key functions in these processes. Yet, specific events regulated by these receptors in the developing pancreas remain unknown. Here, we show that ablation of the β1 integrin gene in developing pancreatic β-cells reduces their ability to expand during embryonic life, during the first week of postnatal life, and thereafter. Mice lacking β1 integrin in insulin-producing cells exhibit a dramatic reduction of the number of β-cells to only ∼18% of wild-type levels. Despite the significant reduction in β-cell mass, these mutant mice are not diabetic. A thorough phenotypic analysis of β-cells lacking β1 integrin revealed a normal expression repertoire of β-cell markers, normal architectural organization within islet clusters, and a normal ultrastructure. Global gene expression analysis revealed that ablation of this ECM receptor in β-cells inhibits the expression of genes regulating cell cycle progression. Collectively, our results demonstrate that β1 integrin receptors function as crucial positive regulators of β-cell expansion.

Early postnatal inhibition of serotonin synthesis results in long-term reductions of perseverative behaviors, but not aggression, in MAO A-deficient mice

Monoamine oxidase (MAO) A, the major enzyme catalyzing the oxidative degradation of serotonin (5-hydroxytryptamine, 5-HT), plays a key role in emotional regulation. In humans and mice, MAO-A deficiency results in high 5-HT levels, antisocial, aggressive, and perseverative behaviors. We previously showed that the elevation in brain 5-HT levels in MAO-A knockout (KO) mice is particularly marked during the first two weeks of postnatal life. Building on this finding, we hypothesized that the reduction of 5-HT levels during these early stages may lead to enduring attenuations of the aggression and other behavioral aberrances observed in MAO-A KO mice. To test this possibility, MAO-A KO mice were treated with daily injections of a 5-HT synthesis blocker, the tryptophan hydroxylase inhibitor p-chloro-phenylalanine (pCPA, 300 mg/kg/day, IP), from postnatal day 1 through 7. As expected, this regimen significantly reduced 5-HT forebrain levels in MAO-A KO pups. These neurochemical changes persisted throughout adulthood, and resulted in significant reductions in marble-burying behavior, as well as increases in spontaneous alternations within a T-maze. Conversely, pCPA-treated MAO-A KO mice did not exhibit significant changes in anxiety-like behaviors in a novel open-field and elevated plus-maze; furthermore, this regimen did not modify their social deficits, aggressive behaviors and impairments in tactile sensitivity. Treatment with pCPA from postnatal day 8 through 14 elicited similar, yet milder, behavioral effects on marble-burying behavior. These results suggest that early developmental enhancements in 5-HT levels have long-term effects on the modulation of behavioral flexibility associated with MAO-A deficiency.

The effect of prenatal exposure of a non-steroidal anti-inflammatory drug on the optic nerve of female rats: a stereological, histological, and electron microscopic study

Objective: Non-steroidal anti-inflammatory drugs (NSAIDs) can have adverse effects for in both mother and fetus following administration during the prenatal period. If given during pregnancy, diclofenac sodium (DS), an NSAID, is given during the pregnancy, may also affect the development of the central nervous system (CNS) or related structures.Methods: Pregnant rats were separated into pure control (PG), saline (SG) and diclofenac groups (DG). A daily dose of 1 mg/kg of DS and 1 mL/kg saline was injected intraperitoneally to the DG and SG groups, respectively, from the 5th gestation day for a 15 day of period; the PG group received no treatment. After spontaneous delivery, female offspring were obtained from all groups. After the 20th week of postnatal life, the animals (n = 6 for each group) were perfused and the right optic nerves were resected. Sections were subjected to stereological and histological analysis.Results: There were no significant differences (p > 0.05) between PG, SG and DG groups with respect to myelin thickness, axonal cross-sectional area, axon numerical density, total section area of optic nerve and axon number.Conclusions: Histological and stereological results indicated that treatment with DS or saline produced undesirable effects on female rat optic nerve development and myelinization with respect to morphology.