Behavioral predictability, i.e., short-term intra-individual variability under relatively constant environmental conditions, has only recently begun to gain attention.
View Article and Find Full Text PDFA study was conducted to determine if multiple exposures to several stress paradigms might affect the anticholinesterase effect of subsequently administered organophosphate insecticide chlorpyrifos. Male Sprague-Dawley rats were subject to daily periods of restraint, swimming, a combination of the two, or neither of the two (controls) (n=8/group) for 5 days per week over a six-week period. The most profound stress, as measured by reduced body weight gain and elevated levels of plasma corticosterone, was swimming.
View Article and Find Full Text PDFRepeated 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 (B(max)) and equilibrium dissociation rate constants (K(d)) 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.
View Article and Find Full Text PDFEffects of chronic exposure to corticosterone in drinking water on corticosterone kinetics, blood chemistry, and concentrations of catecholamines in parts of brain were studied in Long-Evans rats. Rats were randomly grouped into 3 x 2 treatments (n=4), with three treatments of drinking water (tap water, or 2.5% ethanol, or 400 microg/mL of corticosterone in 2.
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