Papel inibidor da influÃncias corticais contralaterais sobre a depressÃo alastrante, em ratos adultos bem-nutridos e precocemente desnutridos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

The effect of contralateral cortical lesion influence on spreading depression (SD) has been studied in 19 well-nourished (fed a commercial diet with 23% protein) and 18 earlymalnourished male Wistar adult rats (suckled by dams fed a deficient diet â the âbasic regional diet, with only 8% protein). SD was evoked on the right frontal cortex at 20min intervals and its propagation was monitored at 2 points on the parietal surface. After a 2h- âbaselineâ recording period, the contralateral cortex was longitudinally cut, with electric knife, in order to interrupt fibers directing to the other hemisphere via corpus callosum (6.7mm extension, 3-5mm deep, 1-2 mm from the midline according to the Paxinos &Watson rat brain atlas). Post-lesion SD recording was continued for 2 more hours. Lesion of fibers directing to corpus callosum was histologically confirmed in all animals. Compared to the baseline values, post-lesion SD-velocities in both well-nourished and malnourished rats increased significantly (well-nourished, 3.34 Â 0.09 vs 4.03 Â 0.14 mm/min; malnourished, 4.08 Â 0.20 vs 4.23 Â 0.29; P≤0.05, paired t-test). After 3-7 days ârecovery periodâ, a second 2h-SD recording session, performed in the same animals, revealed the permanence of the lesion-related increase in SD velocity, indicating that this effect is long-lasting. No significant difference was found in sham-operated rats (21 well-nourished and 21 malnourished).The SDvelocity increase was also observed in an additional well-nourished group (n=8) submitted to midline lesion (callosotomy), suggesting the involvement of callosal fibers on the observed effect. The results support the hypothesis of an inhibitory role of contralateral cortical activity on SD, which seems to be long lasting and is not influenced by early malnutrition

ASSUNTO(S)

desnutriÃÃo influÃncia cortical contralateral malnutrition contralateral cortical influence plasticidade cerebral depressÃo alastrante corpo caloso spreading depression botanica brain plasticity corpus callosum

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