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We examined the effects of chronic activity wheel running on brain monoamines and latency to escape foot shock after prior exposure to uncontrollable, inescapable foot shock. Individually housed young (approximately 50 day) female Sprague-Dawley rats were randomly assigned to standard cages (sedentary) or cages with activity wheels. After 9-12 weeks,(More)
Regional changes in concentrations of brain norepinephrine [NE] and its metabolites after chronic exercise have not been described for exercise protocols not confounded by other stressors. We examined levels of [NE], 3-methoxy-4-hydroxyphenylglycol [MHPG], and 3,4-dihydroxyphenylglycol [DHPG] in the frontal cortex, hippocampus, pons-medulla, and spinal cord(More)
The central nervous system is the principal target of 1,1,1-trichloroethane (TRI), and several studies of this volatile solvent have demonstrated effects on learned animal behaviors. There have been few attempts, however, to quantitatively relate such effects to blood or target organ (brain) solvent concentrations. Therefore, Sprague-Dawley rats trained to(More)
Dose-dependent increases in 3-methoxy-4-hydroxyphenylethyleneglycol sulfate (MOPEG-SO4), a major metabolite of norepinephrine, were produced in the limbic forebrain and cerebral cortex 30 min after the bilateral injection of morphine into the periaqueductal gray (PAG). These effects were also elicited by similar injections of levorphanol. Highly significant(More)
Previous studies have indicated that human exposure to perchloroethylene (PCE) produces subtle behavioral changes and other neurological effects at concentration at or below the current occupational exposure limit. Since comparable effects in animals may be reflected by changes in schedule-controlled operant behavior, the ability of orally administered PCE(More)
The findings summarized in this paper show that norepinephrine turnover in brain is decreased after acute administration of imipramine or desmethylimipramine but tends to increase during chronic administration of these tricyclic antidepressants. Similarly, it appears that there also may be important differences between the effects of acute and chronic(More)
1,1,1-Trichloroethane (TRI) is a commonly used industrial solvent with a considerable potential for inhalation abuse. Previous studies in our laboratory and elsewhere have shown that this agent exerts a suppressant effect on operant responding, as well as a number of additional neurobehavioral effects that are similar to those of central nervous system(More)
The participation of endogenous opiate systems in the induction and expression of learned helplessness (LH) and stress-induced analgesia (SIA) was investigated in rats exposed to escapable and inescapable footshock. Following an initial footshock, analgesia was observed only in those animals that could not control their stress exposure and this SIA was(More)
Analgesia and changes in limbic and cortical concentrations of the major brain noradrenaline metabolite, 3-methoxy-4-hydroxy-phenylethylene glycol sulphate (MOPEG-SO4), were investigated in rats following the bilateral injection of morphine into the periaqueductal gray (PAG). Morphine, at a dose of 5 micrograms per bilateral site, produced a significant(More)