ABSTRACT
Oxidative status was assessed in different areas of the cerebral cortex of male Wistar rats under normal condition and during permanent 24-h focal ischemia. In intact animals, the level of lipid hydroperoxides in the frontal lobes of both hemispheres was by 36% higher than in other cortical areas, while total antioxidant activity was by 25% higher than in other areas. During ischemia, changes in oxidative status were localized only in the ischemic focus and penumbra zone and did not involve other cortical areas. We demonstrated for the first time a neuroprotective effect of therapeutic administration of carnosine in low doses (50 mg/kg) on parameters of the oxidative status under conditions of focal ischemia comparable to its effect of high doses (500 mg/kg) as well as its local effect in the penumbra zone. A dose-dependent effect of carnosine on antioxidant activity in the penumbra zone during ischemia was also demonstrated. These findings confirm effectiveness of not only preventive carnosine administration, but also its application in the postischemic period of the stroke.
Subject(s)
Brain Ischemia/physiopathology , Carnosine/pharmacology , Cerebral Cortex/drug effects , Cerebral Cortex/physiology , Oxidative Stress , Animals , Antioxidants/metabolism , Brain Ischemia/metabolism , Ischemia/drug therapy , Male , Neuroprotective Agents/pharmacology , Rats , Rats, Wistar , Stroke/drug therapyABSTRACT
Study of spatial learning in adult BALB/c mice revealed that a short exposition to the environment (from 3 to 8 minutes) could be enough for spatial information to be fixed in the long-term memory, and affected subsequent learning process in the new environment. Control group, learning in the same maze, followed the "shortest path" principle during formation of the optimal food-obtaining habit. Experimental animals, learning in a slightly changed environment, were unable to apply this rule due to persistent coupling of the new spatial information with the old memory traces which led to constant errors. The obtained effect was observed during the whole learning period and depended neither on frequency nor on interval of repetition during the initial information acquisition. The obtained data testify that memorizing in adult state share the properties with the imprinting process inherent in the early ontogeny. The memory fixation on all development stages seems to be based on a universal mechanism.
