Alterations in Hippocampal
Antioxidant Enzyme Activities and Sympatho-Adrenomedullary
System of Rats in Response to Different Stress Models
S.B. PAJOVIĆ, S. PEJIĆ, V. STOJILJKOVIĆ, Lj. GAVRILOVIĆ, S.
DRONJAK, D.T. KANAZIR
Laboratory of Molecular Biology and Endocrinology, “Vinča
Institute of Nuclear Sciences”, Belgrade, Serbia
Received May 17, 2005
Accepted September 9, 2005
On-line available October 17, 2005
Summary
The study deals with activity of three antioxidant enzymes,
copper, zinc-superoxide dismutase (CuZnSOD), manganese
superoxide dismutase (MnSOD), catalase (CAT) in hippocampus of
rats, following the exposure to single chronic (individual
housing or forced swimming) and acute (immobilization or cold)
stress, as well as to combined chronic/acute stress. In
addition, plasma noradrenaline (NA) and adrenaline (A)
concentrations were measured in the same stress conditions,
because their autooxidation can add to the oxidative stress. We
observed that i) long-term social isolation and repeated forced
swimming had minor effects on plasma catecholamines, but in the
long-term pretreated groups, acute stressors caused profound
elevation NA and A levels, ii) chronic stressors activate
antioxidant enzymes, iii) acute stressors decrease catalase
activity, their effects on CuZnSOD appear to be
stressor-dependent, whereas MnSOD is not affected by acute
stressors, and iv) pre-exposure to chronic stress affects the
antioxidant-related effects of acute stressors, but this effect
depends to a large extent on the type of the chronic stressor.
Based on both metabolic and neuroendocrine data, long-term
isolation appears to be a robust psychological stressor and to
induce a “priming” effect specifically on the CuZnSOD and CAT
activity.
Key words
Stress • Hippocampus • Antioxidant enzymes • Catecholamines
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