Differential effects of social isolation rearing on glutamate- and GABA-stimulated noradrenaline release in the rat prefrontal cortex and hippocampus.

Social isolation rearing (SIR) provides an excellent model of early life adversity to investigate alterations in brain function. Few studies have investigated the effects of SIR on noradrenaline (NE) projections which arise from the locus coeruleus (LC), a system which regulates arousal and attentional processes, including the processing of novelty. In addition, there is a paucity of information on the effects of SIR in females.

Early-Ethanol Exposure Induced Region-Specific Changes in Metabolic Proteins in the Rat Brain: A Proteomics Study.

In utero exposure to alcohol has been shown to cause a spectrum of cognitive and behavioral deficits. This study aimed to explore the long-term effects of early-ethanol exposure on proteins in the brain. Male Sprague-Dawley rat pups were exposed to 12% ethanol (4 g/kg/day i.

Maternal separation stress reduced prenatal-ethanol-induced increase in exploratory behaviour and extracellular signal-regulated kinase activity.

In an attempt to better represent the aetiology of fetal alcohol spectrum disorder (FASD) and the associated psychological deficits, prenatal-ethanol exposure was followed by maternal separation in a rat model in order to account for the effects of early-life adversities in addition to in utero alcohol exposure. Extracellular signal-regulated kinase 1/2 (ERK1/2) and glycogen synthase kinase 3-β (GSK3β) are converging points for many signalling cascades and have been implicated in models of FASD and models of early-life stress. Therefore, these kinases may also contribute to the behavioural changes observed after the combination of both developmental insults.

Notes on the Recent History of Neuroscience in Africa.

Neuroscience began with neuroanatomy and neurosurgery in Egypt more than 5000 years ago. Knowledge grew over time and specialized neurosurgery centers were established in north Africa in the eleventh century. However, it was not until the twentieth century that neuroscience research became established in sub-Saharan Africa.

Epigenetics: a link between addiction and social environment.

The detrimental effects of drug abuse are apparently not limited to individuals but may also impact the vulnerability of their progenies to develop addictive behaviours. Epigenetic signatures, early life experience and environmental factors, converge to influence gene expression patterns in addiction phenotypes and consequently may serve as mediators of behavioural trait transmission between generations. The majority of studies investigating the role of epigenetics in addiction do not consider the influence of social interactions.

Early ethanol exposure and vinpocetine treatment alter learning- and memory-related proteins in the rat hippocampus and prefrontal cortex.

This study investigates the effects of early exposure to ethanol on cognitive function and neural plasticity-related proteins in the rat brain. Sprague-Dawley rats were administered 12% ethanol solution (4 g/kg/day i.p.

Developmental stress elicits preference for methamphetamine in the spontaneously hypertensive rat model of attention-deficit/hyperactivity disorder.

Background: Developmental stress has been hypothesised to interact with genetic predisposition to increase the risk of developing substance use disorders. Here we have investigated the effects of maternal separation-induced developmental stress using a behavioural proxy of methamphetamine preference in an animal model of attention-deficit/hyperactivity disorder, the spontaneously hypertensive rat, versus Wistar Kyoto and Sprague-Dawley comparator strains.

Results: Analysis of results obtained using a conditioned place preference paradigm revealed a significant strain × stress interaction with maternal separation inducing preference for the methamphetamine-associated compartment in spontaneously hypertensive rats.

Genetically determined differences in noradrenergic function: The spontaneously hypertensive rat model.

While genetic predisposition is a major factor, it is not known how development of attention-deficit/hyperactivity disorder (ADHD) is modulated by early life stress. The spontaneously hypertensive rat (SHR) displays the behavioral characteristics of ADHD (poorly sustained attention, impulsivity, hyperactivity) and is the most widely studied genetic model of ADHD. We have previously shown that SHR have disturbances in the noradrenergic system and that the early life stress of maternal separation failed to produce anxiety-like behavior in SHR, contrary to control Sprague-Dawley and Wistar-Kyoto (WKY) who showed typical anxiety-like behavior in later life.

Regional research priorities in brain and nervous system disorders.

The characteristics of neurological, psychiatric, developmental and substance-use disorders in low- and middle-income countries are unique and the burden that they have will be different from country to country. Many of the differences are explained by the wide variation in population demographics and size, poverty, conflict, culture, land area and quality, and genetics. Neurological, psychiatric, developmental and substance-use disorders that result from, or are worsened by, a lack of adequate nutrition and infectious disease still afflict much of sub-Saharan Africa, although disorders related to increasing longevity, such as stroke, are on the rise.

Genetic predisposition and early life experience interact to determine glutamate transporter (GLT1) and solute carrier family 12 member 5 (KCC2) levels in rat hippocampus.

Attention-deficit/hyperactivity disorder (ADHD) is one of the most common child psychiatric disorders. While it is typically treated with medications that target dopamine and norepinephrine transmission, there is increasing evidence that other neurotransmitter systems, such as glutamate and GABA, may be involved. The aetiology of ADHD is unknown; however, there is evidence that early life stress may contribute to the development of the disorder.

Effect of cocaine on striatal dopamine clearance in a rat model of developmental stress and attention-deficit/hyperactivity disorder.

Attention-deficit/hyperactivity disorder (ADHD) and developmental stress are considered risk factors for the development of drug abuse. Though the physiological mechanisms underlying this risk are not yet clear, ADHD, developmental stress and drug abuse are known to share underlying disturbances in dopaminergic neurotransmission. Thus, we hypothesized that clearance of cocaine-induced elevations in striatal dopamine would be prolonged in a rat model of ADHD and that this would be further increased by exposure to developmental stress.

Tat-induced histopathological alterations mediate hippocampus-associated behavioural impairments in rats.

Background: HIV-1 is a global catastrophe, and is exceedingly prevalent in Sub-Saharan Africa. HIV-associated neurocognitive disorder is characterized by symptoms such as motor impairments, a decline in cognition, and behavioural irregularities. The aim of this study was to provide insight into the fundamental behavioural and histopathological mechanisms underlying the development and progression of HIV-1 neuropathology.

Proteomic analysis of maternal separation-induced striatal changes in a rat model of ADHD: The spontaneously hypertensive rat.

Background: Developmental stress increases the risk of developing psychological disturbances and is modelled in rodents by maternal separation (MS). Attention-deficit/hyperactivity disorder (ADHD) is characterised by inattention, hyperactivity and impulsivity and is studied using the spontaneously hypertensive rat (SHR). Previous studies suggested that SHR differ from their progenitor strain, the Wistar-Kyoto (WKY), in their response to developmental stress.

Impaired Energy Metabolism and Disturbed Dopamine and Glutamate Signalling in the Striatum and Prefrontal Cortex of the Spontaneously Hypertensive Rat Model of Attention-Deficit Hyperactivity Disorder.

Attention deficit hyperactivity disorder (ADHD) is a heterogeneous behavioural disorder that affects 3-15 % of children worldwide. Spontaneously hypertensive rats (SHR) display the major symptoms of ADHD (hyperactivity, impulsivity and poor performance in tasks that require sustained attention) and are widely used to model the disorder. The present study aimed to test the hypothesis that SHR have a diminished capacity to generate ATP required for rapid synchronized neuronal firing, failure of which might lead to disturbances in neurotransmission that could contribute to their ADHD-like behaviour.

Effect of diet on brain metabolites and behavior in spontaneously hypertensive rats.

Attention-deficit hyperactivity disorder (ADHD) is a heterogeneous psychiatric disorder affecting 5-10% of children. One of the suggested mechanisms underlying the pathophysiology of ADHD is insufficient energy supply to neurons. Here, we investigated the role of omega 3 fatty acids in altering neural energy metabolism and behavior of spontaneously hypertensive rats (SHR), which is an animal model of ADHD.

Nicotine-stimulated release of [3H]norepinephrine is reduced in the hippocampus of an animal model of attention-deficit/hyperactivity disorder, the spontaneously hypertensive rat.

Attention-deficit/hyperactivity disorder (ADHD) is a heterogeneous, developmental disorder, and is one of the most common child-psychiatric disorders. It is also a risk factor for early smoking and adult nicotine dependence. Nicotine has been shown to improve symptoms associated with ADHD, including problems with attention, working memory and response inhibition.

The interaction between stress and exercise, and its impact on brain function.

In response to acute adversity, emotional signals shift the body into a state that permits rapid detection, identification, and appropriate response to a potential threat. The stress response involves the release of a variety of substances, including neurotransmitters, neurotrophic factors, hormones, and cytokines, that enable the body to deal with the challenges of daily life. The subsequent activation of various physiological systems can be both protective and damaging to the individual, depending on timing, intensity, and duration of the stressor.

Evidence for reduced tonic levels of GABA in the hippocampus of an animal model of ADHD, the spontaneously hypertensive rat.

Recent studies have investigated the role of γ-aminobutyric acid (GABA) in the behavioural symptoms of attention-deficit/hyperactivity disorder (ADHD), specifically in behavioural disinhibition. Spontaneously hypertensive rats (SHR) are widely accepted as an animal model of ADHD, displaying core symptoms of the disorder. Using an in vitro superfusion technique, we have shown that glutamate-stimulated release of radio-actively labelled norepinephrine ([(3)H]NE) from prefrontal cortex and hippocampal slices is greater in SHR than in their normotensive control strain, Wistar-Kyoto rats (WKY), and/or a standard control strain, Sprague-Dawley rats (SD).

A behavioral neuroenergetics theory of ADHD.

Energetic insufficiency in neurons due to inadequate lactate supply is implicated in several neuropathologies, including attention-deficit/hyperactivity disorder (ADHD). By formalizing the mechanism and implications of such constraints on function, the behavioral Neuroenergetics Theory (NeT) predicts the results of many neuropsychological tasks involving individuals with ADHD and kindred dysfunctions, and entails many novel predictions. The associated diffusion model predicts that response times will follow a mixture of Wald distributions from the attentive state, and ex-Wald distributions after attentional lapses.

Maternal separation increases GABA(A) receptor-mediated modulation of norepinephrine release in the hippocampus of a rat model of ADHD, the spontaneously hypertensive rat.

Experiencing early life stress increases the risk of developing a psychiatric disorder later in life, possibly by altering neural networks, such as the locus-coeruleus norepinephrine (LC-NE) system. Whether early life stress affects the LC-NE system directly, or whether the effects are via changes in glutamate and GABA modulation of the LC-NE system, is unclear. Early life stress has been shown to alter glutamate and GABA transmission, and in particular, to alter GABA(A) receptor expression.

The impact of voluntary exercise on relative telomere length in a rat model of developmental stress.

Background: Exposure to early adverse events can result in the development of later psychopathology, and is often associated with cognitive impairment. This may be due to accelerated cell aging, which can be catalogued by attritioned telomeres. Exercise enhances neurogenesis and has been proposed to buffer the effect of psychological stress on telomere length.

Childhood Trauma is Associated with Altered Cortical Arousal: Insights from an EEG Study.

Background: Childhood trauma is associated with psychiatric disorders, yet the underlying psychobiological mechanisms that account for this link are not well understood. Alterations in cortical arousal may, however, play a key role in mediating this association. We hypothesized that childhood trauma would be associated with alterations in arousal during a task that required sustained attention and behavioral inhibition.

The spontaneously hypertensive and Wistar Kyoto rat models of ADHD exhibit sub-regional differences in dopamine release and uptake in the striatum and nucleus accumbens.

The most widely used animal model of attention-deficit/hyperactivity disorder (ADHD) is the spontaneously hypertensive rat (SHR/NCrl), which best represents the combined subtype (ADHD-C). Recent evidence has revealed that a progenitor strain, the Wistar Kyoto from Charles River Laboratories (WKY/NCrl), is useful as a model of the inattentive subtype (ADHD-PI) and the Wistar Kyoto from Harlan Laboratories (WKY/NHsd) and the Sprague Dawley (SD) have been suggested as controls. Dopamine (DA) dysfunction in the striatum (Str) and nucleus accumbens core (NAc) is thought to play a significant role in the pathophysiology of ADHD but data obtained with the SHR is equivocal.