| 1. |
- Archer, Trevor, 1949, et al.
(författare)
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Behavioural supersensitivity following neonatal 6-hydroxydopamine : Attenuation by MK-801
- 2007
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Ingår i: Neurotoxicity research. - 1029-8428 .- 1476-3524. ; 12:2, s. 113-124
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Tidskriftsartikel (refereegranskat)abstract
- Male rat pups were administered 6-hydroxydopamine (6-OHDA, 75 μg, intracisternally, 30 min after desipramine, 25 mg/kg, s.c.) on Days 1 or 2 after birth, or were sham-operated (receiving vehicle). In four experiments, the acute effects of apomorphine, with or without pretreatment with MK-801 (0.03 mg/kg), upon motor activity in test chambers was measured. Acute treatment with apomorphine (0.1 mg/kg) increased locomotor, rearing and total activity markedly compared to both the acute saline administered 6-OHDA rats and the sham-operated rats administered saline. Acute MK-801 (0.03 mg/kg) co-administered shortly before (5 min) apomorphine (0.3 or 1.0 mg/kg) reduced markedly locomotion and total activity in 6-OHDA-treated and sham-operated rats. Rearing behaviour was increased in both the 6-OHDA groups of rats. Acute MK-801 increased activity in the 6-OHDA-treated rats, which was not observed in sham-operated rats. At the 0.3 and 1.0 mg/kg doses of apomorphine, neonatal 6-OHDA treament increased all three parameters of motor activity. Acute treatment with apomorphine (0.1 mg/kg) induced different effects on the motor activity of 6-OHDA-treated and sham-operated mice. In sham-operated rats apomorphine reduced motor activity during the 1st 30-min period but increased locomotion and total activity, but not rearing, during the 2nd and 3rd periods, whereas in 6-OHDA-treated rats, apomorphine increased locomotor, rearing and total activity markedly. Dopamine loss and serotonin elevation in the striatum and olfactory tubercle were confirmed. The present findings confirm the influence of non-competitive glutamate antagonists in attenuating the behavioural supersensitivity to dopamine antagonists.
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| 2. |
- Archer, Trevor, 1949, et al.
(författare)
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Clinical staging in the pathophysiology of psychotic and affective disorders: facilitation of prognosis and treatment.
- 2010
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Ingår i: Neurotoxicity research. - : Springer Science and Business Media LLC. - 1476-3524 .- 1029-8428. ; 18:3-4, s. 211-28
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Tidskriftsartikel (refereegranskat)abstract
- The prevailing utility, and indeed necessity, of clinical staging models applied in considerations of neuropsychiatric disease progressions is discussed from the perspectives of schizophrenia spectrum disorders and affective disorders, cannabis in schizopsychotic disorder, incidences of affect and psychosis, staging disorders in aging and the indices and prevalence of apathy. There would appear to be a strong current consensus that the pursuit of clinical staging of these and other brain disease states has contributed a systematic conceptual instrument to facilitate the better understanding, diagnosis, prognosis and treatment as derived from a multitude of genetic predispositions, symptoms and syndromes, early-onset and prodromal phases, recurrences and relapses, that have complicated the situation of the patient. Through a staging determination of the disorder, elements of diagnosis will describe the progression of symptoms/syndromes through pre-onset, prodromal, first-episode, recurrences and relapses, and treatment resistance thereby facilitating the eventual prognosis, intervention alternatives and treatment. This approach varies from observations of individuals at early stages of development (infancy, childhood, adolescece) to early middle age, in the case of diseases expressed through the aging processes. Essentially, the major contribution of the staging model may lie in the early identification, diagnosis, and treatments of disorders that afflict the brain and central nervous system.
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| 3. |
- Archer, Trevor, 1949, et al.
(författare)
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Delayed Exercise-Induced Functional and Neurochemical Partial Restoration Following MPTP
- 2012
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Ingår i: Neurotoxicity research. - : Springer Science and Business Media LLC. - 1029-8428 .- 1476-3524. ; 21:2, s. 210-221
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Tidskriftsartikel (refereegranskat)abstract
- In two experiments, MPTP was administered to C57/BL6 mice according to a single-dose weekly regime (MPTP: 1 x 30 mg/kg on the fifth day of the week, Friday, over 4 weeks) with vehicle group (Vehicle: 1 x 5 ml/kg) treated concurrently. Exercise schedules (delayed) were introduced either at the beginning of the week after the second MPTP injection (MPTP + Exercise(2) group), or at the beginning of the week after the fourth MPTP injection (MPTP + Exercise(4) group). Wheel-running was provided on the first 4 days of each week (Monday-Thursday) more than 30-min periods. In Experiment I, wheel-running exercise was introduced either after 2 or 4 weeks after MPTP/Vehicle. MPTP and Vehicle groups not provided access to the running wheels were placed in single cages within the wheel-running room over 30-min concomitantly with the wheel-running groups. In Experiment II, wheel-running exercise was introduced 2 weeks after MPTP/Vehicle but a no-exercise control group with non-revolving wheel included (MPTP-Wheel). In both experiments, spontaneous motor activity tests during 60-min intervals were performed at the end (Fridays) of weeks 1, 2, 3, 4, 6, 8, and 10, where the week on which the first injection of MPTP was the first week; in the case of weeks 1-4, this was immediately before MPTP/Vehicle injections. It was observed that the introduction of the exercise schedule after the second MPTP injection, but not after the fourth injection, restored motor activity that had been markedly elevated by the end of the tenth week. Subthreshold administration of l-dopa tests was performed after the spontaneous motor activity tests 6, 8 and 10; these indicated significant effects of exercise, MPTP + Exercise(2) group, on Tests 6 and 8, but not Test 10. The physical exercise schedule in that group also showed markedly attenuated loss of dopamine (DA). Restoration of MPTP-induced motor activity deficits and DA loss was a function of the point at which exercise was introduced, in the present case after two administrations of the neurotoxin. In Experiment II, physical exercise markedly attenuated the hypokinesic effect of MPTP in the exercise condition, MPTP-exercise, but not in the non-exercise conditions, MPTP-Cage and MPTP-Wheel, for both spontaneous motor activity and l-dopa-induced activity. MPTP-induced loss of DA was also attenuated by exercise.
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| 4. |
- Archer, Trevor, 1949, et al.
(författare)
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Epigenetics and biomarkers in the staging of neuropsychiatric disorders.
- 2010
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Ingår i: Neurotoxicity research. - : Springer Science and Business Media LLC. - 1476-3524 .- 1029-8428. ; 18:3-4, s. 347-66
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Tidskriftsartikel (refereegranskat)abstract
- Epigenetics, or alterations in the phenotype or gene expression due to mechanisms other than changes in the underlying DNA sequence, reflects the sensitivity and responsiveness of human and animal brains in constantly varying circumstances regulating gene expression profiles that define the biomarkers and present the ultimate phenotypical outcomes, such as cognition and emotion. Epigenetics is associated with functionally relevant alterations to the genome in such a fashion that under the particular conditions of early, adolescent, and adult life, environmental signals may activate intracellular pathways that remodel the "epigenome," triggering changes in gene expression and neural function. Thus, genetic influences in neuropsychiatric disorders that are subject to clinical staging, epigenetics in schizophrenia, epigenetic considerations in the expression of sensorimotor gating resulting from disease conditions, biomarkers of drug use and addiction, current notions on the role of dopamine in schizophrenia spectrum disorders, and the discrete interactions of biomarkers in persistent memory were to greater or lesser extents reflected upon. The relative contributions of endophenotypes and epistasis for mediating epigenetic phenomena and the outcomes as observed in the analysis of biomarkers appear to offer a multitude of interactive combinations to further complicate the labyrinthine machinations of diagnosis, intervention, and prognosis.
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| 5. |
- Archer, Trevor, 1949, et al.
(författare)
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Influence of Physical Exercise on Neuroimmunological Functioning and Health : Aging and Stress
- 2011
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Ingår i: Neurotoxicity research. - : Springer Science and Business Media LLC. - 1029-8428 .- 1476-3524. ; 20:1, s. 69-83
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Tidskriftsartikel (refereegranskat)abstract
- Chronic and acute stress, with associated pathophysiology, are implicated in a variety of disease states, with neuroimmunological dysregulation and inflammation as major hazards to health and functional sufficiency. Psychosocial stress and negative affect are linked to elevations in several inflammatory biomarkers. Immunosenescence, the deterioration of immune competence observed in the aged aspect of the life span, linked to a dramatic rise in morbidity and susceptibility to diseases with fatal outcomes, alters neuroimmunological function and is particularly marked in the neurodegenerative disorders, e.g., Parkinson's disease and diabetes. Physical exercise diminishes inflammation and elevates agents and factors involved in immunomodulatory function. Both the alleviatory effects of life-long physical activity upon multiple cancer forms and the palliative effects of physical activity for individuals afflicted by cancer offer advantages in health intervention. Chronic conditions of stress and affective dysregulation are associated with neuroimmunological insufficiency and inflammation, contributing to health risk and mortality. Physical exercise regimes have induced manifest anti-inflammatory benefits, mediated possibly by brain-derived neurotrophic factor. The epidemic proportions of metabolic disorders, obesity, and diabetes demand attention; several variants of exercise regimes have been found repeatedly to induce both prevention and improvement under both laboratory and clinical conditions. Physical exercise offers a unique non-pharmacologic intervention incorporating multiple activity regimes, e.g., endurance versus resistance exercise that may be adapted to conform to the particular demands of diagnosis, intervention and prognosis inherent to the staging of autoimmune disorders and related conditions.
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| 6. |
- Archer, Trevor, 1949
(författare)
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Influence of Physical Exercise on Traumatic Brain Injury Deficits: Scaffolding Effect.
- 2012
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Ingår i: Neurotoxicity research. - : Springer Science and Business Media LLC. - 1476-3524 .- 1029-8428. ; 21:4, s. 418-434
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Tidskriftsartikel (refereegranskat)abstract
- Traumatic brain injury (TBI) may be due to a bump, blow, or jolt to the head or a penetrating head injury that disrupts normal brain function; it presents an ever-growing, serious public health problem that causes a considerable number of fatalities and cases of permanent disability annually. Physical exercise restores the healthy homeostatic regulation of stress, affect and the regulation of hypothalamic-pituitary-adrenal axis. Physical activity attenuates or reverses the performance deficits observed in neurocognitive tasks. It induces anti-apoptotic effects and buttresses blood-brain barrier intactness. Exercise offers a unique non-pharmacologic, non-invasive intervention that incorporates different regimes, whether dynamic or static, endurance, or resistance. Exercise intervention protects against vascular risk factors that include hypertension, diabetes, cellular inflammation, and aortic rigidity. It induces direct changes in cerebrovasculature that produce beneficial changes in cerebral blood flow, angiogenesis and vascular disease improvement. The improvements induced by physical exercise regimes in brain plasticity and neurocognitive performance are evident both in healthy individuals and in those afflicted by TBI. The overlap and inter-relations between TBI effects on brain and cognition as related to physical exercise and cognition may provide lasting therapeutic benefits for recovery from TBI. It seems likely that some modification of the notion of scaffolding would postulate that physical exercise reinforces the adaptive processes of the brain that has undergone TBI thereby facilitating the development of existing networks, albeit possibly less efficient, that compensate for those lost through damage.
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| 7. |
- Archer, Trevor, 1949, et al.
(författare)
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Neurodegenerative Aspects in Vulnerability to Schizophrenia Spectrum Disorders
- 2014
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Ingår i: Neurotoxicity Research. - : Springer Science and Business Media LLC. - 1029-8428 .- 1476-3524. ; 26:4, s. 400-413
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Tidskriftsartikel (refereegranskat)abstract
- The neurodegenerative and neurotoxic aspects of schizophrenia and/or psychosis involve genetic, epigenetic, and neurotoxic propensities that impinge upon both the symptom domains and the biomarkers of the disorder, involving cellular apoptosis/excitotoxicity, increased reactive oxygen species formation, viral and bacterial infections, anoxic birth injury, maternal starvation, drugs of abuse, particularly cannabis, metabolic accidents, and other chemical agents that disrupt normal brain development or the integrity of brain tissues. Evidence for premorbid and prodromal psychotic phases, aspects of neuroimaging, dopamine, and psychosis vulnerability, and perinatal aspects provide substance for neurodegenerative influences. Not least, the agencies of antipsychotic contribute to the destructive spiral that disrupts normal structure and function. The etiopathogenesis of psychosis is distinguished also by disruptions of the normal functioning of the neurotrophins, in particular brain-derived neurotrophic factor, dyskinesic aspects, immune system disturbances, and metabolic aspects. Whether detrimental to neurodevelopment or tissue-destructive, or an acceleration of neurotoxic pathways, the notion of neurodegeneration in the pathophysiology of schizophrenia spectrum and psychotic disorders continues to gather momentum.
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| 8. |
- Archer, Trevor, 1949, et al.
(författare)
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Physical exercise alleviates ADHD symptoms: regional deficits and development trajectory.
- 2012
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Ingår i: Neurotoxicity research. - : Springer Science and Business Media LLC. - 1029-8428 .- 1476-3524. ; 21:2, s. 195-209
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Tidskriftsartikel (refereegranskat)abstract
- The heterogeneous, chronic, and proliferating aspect of attention deficit hyperactivity disorder (ADHD) and comorbidities covers heritability, cognitive, emotional, motor, and everyday behavioral domains that place individuals presenting the condition at some considerable disadvantage. Disruption of "typical developmental trajectories" in the manifestation of gene-environment interactive predispositions implies that ADHD children and adolescents may continue to perform at defective levels as adults with regard to academic achievement, occupational enterprises, and interpersonal relationships, despite the promise of pharmacotherapeutic treatments. Physical exercise provides a plethora of beneficial effects against stress, anxiety, depression, negative affect and behavior, poor impulse control, and compulsive behavior concomitant with improved executive functioning, working memory and positive affect, as well as improved conditions for relatives and care-givers. Brain-derived neurotrophic factor, an essential element in normal brain development that promotes health-associated behaviors and quality-of-life, though reduced in ADHD, is increased markedly by the intervention of regular physical exercise. Functional, regional, and biomarker deficits, as well as hypothalamic-pituitary-adrenal disruptions, have been improved through regular and carefully applied exercise programs. In view of the complications involving ADHD with co-morbidities, such as obesity, the influence of regular physical exercise has not been found negligible. Physical exercise bestows a propensity for eventual manifestation of "redifferentiated" developmental trajectories that may equip ADHD adults with a prognosis that is more adaptive functionally, independent of the applications of other therapeutic agents and treatments.
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| 9. |
- Archer, Trevor, 1949, et al.
(författare)
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Physical Exercise Alleviates Health Defects, Symptoms, and Biomarkers in Schizophrenia Spectrum Disorder
- 2015
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Ingår i: Neurotoxicity Research. - : Springer Science and Business Media LLC. - 1029-8428 .- 1476-3524. ; 28:3, s. 268-280
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Forskningsöversikt (refereegranskat)abstract
- Schizophrenia spectrum disorders are characterized by symptom profiles consisting of positive and negative symptoms, cognitive impairment, and a plethora of genetic, epigenetic, and phenotypic biomarkers. Assorted animal models of these disorders and clinical neurodevelopmental indicators have implicated neurodegeneration as an element in the underlying pathophysiology. Physical exercise or activity regimes-whether aerobic, resistance, or endurance-ameliorate regional brain and functional deficits not only in affected individuals but also in animal models of the disorder. Cognitive deficits, often linked to regional deficits, were alleviated by exercise, as were quality-of-life, independent of disorder staging and risk level. Apoptotic processes intricate to the etiopathogenesis of schizophrenia were likewise attenuated by physical exercise. There is also evidence of manifest benefits endowed by physical exercise in preserving telomere length and integrity. Not least, exercise improves overall health and quality-of-life. The notion of scaffolding as the outcome of physical exercise implies the "buttressing" of regional network circuits, neurocognitive domains, anti-inflammatory defenses, maintenance of telomeric integrity, and neuro-reparative and regenerative processes.
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| 10. |
- Archer, Trevor, 1949, et al.
(författare)
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Physical Exercise Attenuates MPTP-Induced Deficits in Mice
- 2010
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Ingår i: Neurotoxicity research. - : Springer Science and Business Media LLC. - 1029-8428 .- 1476-3524. ; 18:3-4, s. 313-327
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Tidskriftsartikel (refereegranskat)abstract
- Two experiments were performed to investigate the effects of physical exercise upon the hypokinesia induced by two different types of MPTP administration to C57/BL6 mice. In the first, mice were administered either the standard MPTP dose (2 x 20 or 2 x 40 mg/kg, 24-h interval) or vehicle (saline, 5 ml/kg); and over the following 3 weeks were given daily 30-min period of wheel running exercise over five consecutive days/week or placed in a cage in close proximity to the running wheels. Spontaneous motor activity testing in motor activity test chambers indicated that exercise attenuated the hypokinesic effects of both doses of MPTP upon spontaneous activity or subthreshold l-Dopa-induced activity. In the second experiment, mice were either given wheel running activity on four consecutive days (30-min period) or placed in a cage nearby and on the fifth day, following motor activity testing over 60 min, injected with either MPTP (1 x 40 mg/kg) or vehicle. An identical procedure was maintained over the following 4 weeks with the exception that neither MPTP nor vehicle was injected after the fifth week. The animals were left alone (without either exercise or MPTP) and tested after 2- and 4-week intervals. Weekly exercise blocked, almost completely, the progressive development of severe hypokinesia in the MPTP mice and partially restored normal levels of activity after administration of subthreshold l-Dopa, despite the total absence of exercise following the fifth week. In both experiments, MPTP-induced loss of dopamine was attenuated by the respective regime of physical exercise with dopamine integrity more effectively preserved in the first experiment. The present findings are discussed in the context of physical exercise influences upon general plasticity and neuroreparative propensities as well as those specific for the nigrostriatal pathway.
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