Examination of Concurrent Exposure to Repeated Stress and Chlorpyrifos on Cholinergic, Glutamatergic, and Monoamine Neurotransmitter Systems in Rat Forebrain Regions

Repeated stress has been reported to cause reversible impairment in the central nervous system (CNS). It was proposed that alterations in glutamatergic, cholinergic, and monoamine neurotransmitter systems after exposure to stress are initial CNS events contributing to this impairment and that exacerbation could occur with concurrent exposure to cholinesterase inhibitors. Effects of concurrent exposure to repeated stress and chlorpyrifos on activities of acetylcholinesterase (AChE), carboxylesterase, and choline acetyltransferase (ChAT); concentrations of excitatory amino acids, monoamines, and their metabolites; and maximum binding densities ( Bmax) and equilibrium dissociation rate constants ( Kd) of glutamatergic N-methyl-d-aspartate (NMDA) and total muscarinic cholinergic receptors were studied in the blood, hippocampus, cerebral cortex, or hypothalamus of adult Long-Evans rats. Stress treatments extended over 28 days included (1) control rats handled 5 days/week; (2) rats restrained 1 h/day for 5 days/week; (3) rats swum 30 min for 1 day/week; or (4) rats restrained 4 days/week and swum for 1 day/week. On day 24, each stress treatment group was randomly divided and injected either with corn oil or chlorpyrifos, 160 mg/kg subcutaneously (sc) (60% of the maximum tolerated dose), 4 h after restraint. Blood and brain tisssues were collected on day 28. Rats restrained and swum had a statistical trend toward increasing concentrations of glutamate in the hippocampus when compared to rats only swum ( p = .064). Chlorpyrifos administration decreased restraint-induced elevated aspartate in the hippocampus, and decreased Bmax of total muscarinic receptors in the cerebral cortex. In addition, chlorpyrifos decreased Bmax and Kd of total muscarinic receptors in the cerebral cortex of swum rats. Results demonstrated that chlorpyrifos inhibited AChE activity in blood, cerebral cortex, and hippocampus, but stress did not affect AChE activity. Carboxylesterase activity was inhibited by chlorpyrifos and by repeated restraint with swim. Swim stress decreased concentrations of norepinephrine in the hippocampus and hypothalamus, and increased concentrations of dopamine and its metabolite, DOPAC, in the hypothalamus. Both stress and chlorpyrifos altered serotonin concentrations, and the interactions of repeated stress and chlorpyrifos on serotonin approached significance in the hippocampus ( p = .06) and hypothalamus ( p = .08). Therefore, stress models were demonstrated to alter glutamatergic and monoamine responses, whereas chlorpyrifos alone had effects on cholinergic and monoamine systems in the rat CNS. However, the interactions between stress and chlorpyrifos significant at p < 0.05 were restricted to attenuation of elevated aspartate in the hippocampus of restrained with swim rats and decreased Kd of acetylcholine receptors in the cerebral cortex of swum rats and restrained rats.

The Bioinformatics of Integrative Medical Insights: Proposals for an International Psycho-Social and Cultural Bioinformatics Project

We propose the formation of an International Psycho-Social and Cultural Bioinformatics Project (IPCBP) to explore the research foundations of Integrative Medical Insights (IMI) on all levels from the molecular-genomic to the psychological, cultural, social, and spiritual. Just as The Human Genome Project identified the molecular foundations of modern medicine with the new technology of sequencing DNA during the past decade, the IPCBP would extend and integrate this neuroscience knowledge base with the technology of gene expression via DNA/proteomic microarray research and brain imaging in development, stress, healing, rehabilitation, and the psychotherapeutic facilitation of existentional wellness. We anticipate that the IPCBP will require a unique international collaboration of, academic institutions, researchers, and clinical practioners for the creation of a new neuroscience of mind-body communication, brain plasticity, memory, learning, and creative processing during optimal experiential states of art, beauty, and truth. We illustrate this emerging integration of bioinformatics with medicine with a videotape of the classical 4-stage creative process in a neuroscience approach to psychotherapy.

Mental retadation: a MRI study of 146 Brazilian children

We report results of a magnetic ressonance imaging (MRI) study of 146 Brazilian children, whose intelligence quotient scored less than 70. 50% of MRI examinations did not exhibit any signal of structural lesion (N group), whereas a focal thinning at the junction of the body and splenium of the corpus callosum; ventricular asymmetry; periventricular leukomalacia; gliosis and arachnoid cysts were among the most frequent findings in the remaining of subjects (L group). Maternal stress and altered blood pressure were the most frequent findings in the pre-natal history of both N and L children. Familial antecedents of mental deficiency were reported in 30% of both groups, whereas familiar history of alcoholism was important in N group (60% in N versus 0% in L groups). Neuropsychomotor development was delayed in 80% of the children in both groups. Aggressiveness is the most frequent finding in the post-natal children history.

Multiple vaccine and pyridostigmine interactions: Effects on EEG and sleep in the common marmoset

Following active service during the 1990/1991 Gulf conflict, a number of UK and US veterans presented with a diverse range of symptoms, collectively known as Gulf Veterans' Illnesses (GVI). The administration of vaccines and/or the pretreatment against possible nerve agent poisoning, pyridostigmine bromide (PB), given to Armed Forces personnel during the Gulf conflict has been implicated as a possible factor in the aetiology of these illnesses. The possibility that long-term health effects may result from the administration of these vaccines (anthrax, pertussis, plague, yellow fever, polio, typhoid, tetanus, hepatitis B, meningococcal meningitis and cholera) and/or PB, have been investigated using a non-human primate model, the common marmoset. This paper reports the results from two aspects of the study, brain electrical activity (EEG, collected during performance of a touchscreen mediated discrimination task) and sleep. There were no marked long-term changes in EEG or sleep patterns that could be attributed to vaccines and/or PB administration. The changes that were detected were predominantly time related and independent of treatment. Where statistical differences were detected between treatments, the magnitudes of the difference were relatively minor and therefore not regarded as having long term biological significance.

Multiple vaccine and pyridostigmine interactions: Effects on cognition, muscle function and health outcomes in marmosets

Following active service during the 1990/1991 Gulf Conflict, a number of UK and US veterans presented with a diverse range of symptoms, collectively known as Gulf Veterans Illnesses (GVI). The administration of vaccines and/or the pretreatment against possible nerve agent poisoning, pyridostigmine bromide (PB), given to armed forces personnel during the Gulf Conflict has been implicated as a possible factor in the aetiology of these illnesses. The possibility that long-term health effects may result from the administration of these vaccines (anthrax, pertussis, plague, yellow fever, polio, typhoid, tetanus, hepatitis B, meningococcal meningitis and cholera) and/or PB, have been investigated using a non-human primate model, the common marmoset. This paper reports the results from three aspects of the study, cognitive behaviour (performance of a touchscreen mediated discrimination task), muscle function (performance of a simple strength test) and general health. There were no marked long-term changes in cognition, muscle function or health that could be attributed to vaccines and/or PB administration. Statistical differences related to treatments were only observed in two aspects of cognition and one of clinical chemistry. These changes were transient in nature and their magnitude were minor and, in consequence, was not regarded as having long-term biological significance.

Muscarinic modulations of neuronal anticholinesterase responses

Anticholinesterases (antiChEs) are increasingly used for treating patients with neurodegenerative diseases, but the dependence of their effects on the integrity of cholinergic functions has not yet been analyzed at the molecular level. Here, we report that manipulation of muscarinic neurotransmission confers drastic changes on antiChE responses in the rat brain. In the brains of naïve, un-stressed rats, the irreversible organophosphate antiChE, diisopropylfluorophosphonate (DFP) induced post-treatment accumulation of catalytically active G1 monomers of acetylcholinesterase (AChE). Pre-treatment with the selective M1 muscarinic antagonist, pirenzepine, but not the general muscarinic antagonist, scopolamine, attenuated this G1 increase. DFP-enhanced AChE gene expression was accompanied by diverted splicing from the primary AChE-S mRNA variant, encoding G4 synaptic membrane AChE-S tetramers, to "readthrough" AChE-R mRNA, which encodes soluble G1 monomers. Both the mRNA increase and the shifted splicing were long lasting (>24 h) and common to the parietal cortex and hippocampal CA1 and CA3 neurons. Importantly, the splicing shift was maximal under DFP alone, as compared with sham-injected rats, and virtually preventable by pre-treatment with pirenzepine. In contrast, induction of AChE transcription was less dependent on muscarinic function, resulting in AChE-S but not AChE-R increases. Our findings demonstrate distinct regulation of the enhanced transcription and the alternative splicing reactions to antiChE treatment and shed new light on the differential responses to antiChEs of demented patients with increasingly impaired cholinergic neurotransmission.

Prospects for exploring the molecular-genomic foundations of therapeutic hypnosis with DNA microarrays

A new perspective on how therapeutic hypnosis and neuroscience may be integrated on the molecular-genomic level is offered as a guide for basic research and clinical applications. An update of Watson and Crick's original formulation of molecular biology is proposed to illustrate how psychosocial experiences modulate gene expression, protein synthesis, and brain plasticity during memory trace reactivation for the reorganization of neural networks that encode fear, stress, and traumatic symptoms. Examples of the scientific literature on DNA microarrays are used to explore how this new technology could integrate therapeutic hypnosis, neuroscience, and psychosocial genomics as a new foundation for mind-body medicine. Researchers and clinicians in therapeutic hypnosis need to partner with colleagues in neuroscience and molecular biology that utilize DNA microarray technology. It is recommended that hypnotic susceptibility scales of the future incorporate gene expression data to include the concept of "embodied imagination" and the "ideo-plastic faculty" on a molecular-genomic level as well as the psychological and behavioral level of ideomotor and ideosensory responses that are currently assessed.

Excess "read-through" acetylcholinesterase attenuates but the "synaptic" variant intensifies neurodeterioration correlates

Acute stress increases the risk for neurodegeneration, but the molecular signals regulating the shift from transient stress responses to progressive disease are not yet known. The "read-through" variant of acetylcholinesterase (AChE-R) accumulates in the mammalian brain under acute stress. Therefore, markers of neurodeterioration were examined in transgenic mice overexpressing either AChE-R or the "synaptic" AChE variant, AChE-S. Several observations demonstrate that excess AChE-R attenuates, whereas AChE-S intensifies, neurodeterioration. In the somatosensory cortex, AChE-S transgenics, but not AChE-R or control FVB/N mice, displayed a high density of curled neuronal processes indicative of hyperexcitation. In the hippocampus, AChE-S and control mice, but not AChE-R transgenics, presented progressive accumulation of clustered, heat shock protein 70-immunopositive neuronal fragments and displayed a high incidence of reactive astrocytes. Our findings suggest that AChE-R serves as a modulator that may play a role in preventing the shift from transient, acute stress to progressive neurological disease.

Tracking cholinergic pathways from psychological and chemical stressors to variable neurodeterioration paradigms

Cholinergic hyperexcitation can be induced by both acute psychological stress and exposure to acetylcholinesterase inhibitors. Both factors are known risk factors for delayed neurodeterioration processes such as Alzheimer's disease and Parkinson's disease. Recent publications on the involvement of cholinergic pathways in these and other neurodeterioration syndromes are reviewed.