Early malnutrition and changes in the induced release of noradrenaline in the prefrontal cortex of adult rats.

The influence of early protein-energy malnutrition on the induced release of noradrenaline in the rat prefrontal cortex was studied: (i) by evaluating in vivo the release of the neurotransmitter as revealed by changes in the ability of pyramidal cells to integrate transient transmembrane currents generated by discrete packets of noradrenaline released by repetitive electrical stimulation of the locus coeruleus; and (ii) by measuring in vitro the potassium-induced release of 3H-noradrenaline in slices obtained from the brain frontal pole. Both electrophysiological and neurochemical data show that, in malnourished rats, weak stimulation produces an increased release, whereas strong stimulation results in a decreased release of the neurotransmitter. The results provide direct evidence that malnutrition alters the release of noradrenaline at the cortical level. Since the prefrontal cortex is involved in cognitive processing, the present results could provide functional evidence linking nutritional and behavioral deficits.