Long-lasting Effects of Early Environmental Stimulation on Cortical Spreading Depression in Normal and Early Malnourished Adult Rats

Abstract

We investigated the effects of early environmental stimulation on spreading depression in the cerebral cortex of male Wistar adult (90 day old) well-nourished (23% protein diet) and early malnourished (8% protein) rats. Environmental stimulation was performed during the suckling period or after weaning. Control rats were housed in a standard environment. Environmental stimulation after weaning produced a reduction of body weights in well-nourished rats, and an increase in wet, but not dry brain weights, in malnourished rats. Environmental stimulation during suckling was associated with reduced spreading depression velocities in the malnourished, but not in the well-nourished group. In well-nourished rats stimulated during suckling, spreading depression velocities in the occipital and parietal regions of the same hemisphere were significantly different, the occipital area presenting lower values than the parietal region. The results indicate that environmental conditions prevailing during brain development can alter electrophysiological parameters of spreading depression of adult rats, the suckling period being more susceptible to such environmental conditions and the occipital cortex being more affected than the parietal region. Data also suggest that the nutritional status can influence brain spreading depression responses to environmental stimulation, malnourished rats being more effected than the well-nourished ones.

Nutrition-dependent influence of peripheral electrical stimulation during brain development on cortical spreading depression in weaned rats

“…Concerning nutritional deficiency, CSD-susceptibility was increased in rats malnourished early in life, as judged by its higher CSD velocities, in comparison to the well-nourished rats, confirming previous studies (Andrade et al 1990;Rocha-De-Melo and Guedes 1997;Santos Monteiro et al 2000;Amâncio-dosSantos et al 2006). Deficient myelination, increased brain cell packing density, altered neuron-to-glia ratio and synaptic neurotransmitters are the most suggested mechanisms to explain the effect of early malnutrition on cortical CSD (De Luca et al 1977;Rocha-DeMelo and Guedes 1997).…”

Manipulation of rat litter size during suckling influences cortical spreading depression after weaning and at adulthood

“…Disturbances in cognitive development have also been associated with the deficiency of specific compounds of the breast milk, like polyunsaturated fatty acids (Lucas 1997). In addition, experimental results have unequivocally demonstrated that the cerebral cortex is very sensitive to nutritional and plasticity changes (Leuba and Rabinowicz 1979;Sirevaag et al 1988;Borba et al 2000;Santos-Monteiro et al 2000). These data collectively raise the question of how electrophysiological changes in energy-challenging phenomena like SD would be associated with these developmental disturbances.…”

Malnutrition and REM-sleep Deprivation Modulate in Rats the Impairment of Spreading Depression by a Single Sub-convulsing Dose of Pilocarpine

“…During SD, the ECoG activity became depressed and the amplitudes and durations of the DC-recording accompanying SD ranged from -10 to -20mVand from 40 to 80s, respectively. After SD, electrographic cortical recovery took 5-10 min to be completed and usually an interval of at least 20 min between stimulations was kept, as usual (Guedes and Do Carmo, 1980;Santos-Monteiro et al, 2000;Guedes et al, 2002). These baseline SD-recordings are illustrated in the left part of each panel of Fig.…”