RESUMO
The effect of injections of selected amino acids and of N-methyl-D-aspartate (NMDA); morphine; and NMDA, nitric oxide (NO), and opioid inhibitors given before a maze-learning was investigated. Thirsty crickets (Pteronemobius sp) were trained to turn only to one side of a symmetrical Y-shaped maze using reinforcements with water. The insects retained the learned task 24 h later. N2 anoxia applied immediately after training produced retrograde amnesia. Injections of alanine (Ala), arginine (Arg), glutamine (Gln), morphine, or NMDA prior to training blocked the amnesic action of anoxia. Naloxone, an opioid antagonist, blocked long-term memory formation, but not learning, whereas hemoglobin or 2-amino-5-phosphonovaleric acid (APV), NO and NMDA antagonists respectively, blocked both. The antiamnesic effect of Morphine and Arg, but not that of Ala or NMDA was blocked by naloxone. The results suggest involvement of NMDA receptors and NO and thus of long-term potentiation phenomena in learning and in memory consolidation, whereas other neuromodulatory systems related to Arg, and opiate receptors, are only involved in memory consolidation.
Assuntos
Aminoácidos/fisiologia , Endorfinas/fisiologia , Gryllidae/fisiologia , Aprendizagem/efeitos dos fármacos , Memória/efeitos dos fármacos , Óxido Nítrico/fisiologia , 2-Amino-5-fosfonovalerato/farmacologia , Aminoácidos/farmacologia , Animais , Condicionamento Operante/efeitos dos fármacos , Endorfinas/antagonistas & inibidores , Feminino , Hemoglobinas/farmacologia , N-Metilaspartato/antagonistas & inibidores , N-Metilaspartato/farmacologia , Naloxona/farmacologia , Óxido Nítrico/antagonistas & inibidores , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Receptores de N-Metil-D-Aspartato/efeitos dos fármacos , Receptores de N-Metil-D-Aspartato/fisiologiaRESUMO
A randomized, prospective study was performed on 73 male children between 3 and 14 months of age with mild to moderate dehydration caused by acute diarrhea, and who were rehydrated with WHO-ORS, and then at 4 h after admission were fed either cow's milk or an experimental diet based on chicken, plantain, and coconut oil. There were no statistically significant differences in the admission characteristics. The group of children fed cow's milk had a higher total volume of diarrheic evacuations (p less than 0.05). The average duration of diarrhea was 20 h shorter in the group of infants on the milk-free formula. A significant correlation was observed between the volume of diarrhea and the WHO-ORS consumed during the first 48 h, but not to the volume of diet intake.