Luciane da Silva

Effect of undernutrition on GMP-PNP binding and adenylate cyclase activity from rat brain

Abstract1. Undernutrition is an insult that affects brain development and functioning. Considering that signaling through metabotropic receptors/G proteins is critical for normal synaptic transmission and contributes to CNS development and synaptic plasticity, the present study investigated the effects of pre- and postnatal protein deprivation (diet: 8% protein; normonourished group: 25% protein) on brain signal transduction by G proteins.2. Undernutrition decreased the [3H] GMP-PNP binding to G proteins and AC activity, in neural plasma synaptic membranes of 21- and 75-day-old rats. This effect was less pronounced or even absent in old rats.3. Ontogenetically, the dietary treatment effect might be interpreted as a retarded development associated with protein malnutrition.

Glucose and Lactate Utilization by the Amygdala of Male and Female Rats

Gonadal hormones appear to modulate brain energy metabolism, and morphological and functional sexual differences are found in the amygdaloid complex (AC) of rats. Our aim was to study the CO2 production and lipid synthesis, measured by the rate of L-[U-14C]lactate or D-[U-14C]glucose utilization (in pmol.hr−1.mg−1), by AC slices in vitro of male and female rats. Lactate was more used than glucose as energy substrate (p < 0.01) but no sex-related difference was observed in glucose or lactate oxidation to CO2 (p > 0.05) or on lipid synthesis obtained from both substrates (p > 0.05). In addition, there was no effect of the estrous cycle on lactate oxidation to CO2 by the AC of females (p > 0.05). Based on the present data, it appears that the endogenous normal levels of gonadal hormones are not able to promote sex-related differences in the in vitro glucose or lactate utilization by the AC of rats.