Early malnutrition alters the effect of chlordiazepoxide on inhibitory avoidance.
In order to study the functional consequences of brain changes caused by early malnutrition, rats were fed a protein-deficient diet from birth until 49 days of age and a balanced diet from day 50 to day 70. The animals were submitted to a step-down inhibitory avoidance task and to the flinch-jump nociceptive test at 49 and 70 days of age. Malnourished rats showed longer step-down latencies and lower flinch and jump thresholds than eutrophic animals. Chlordiazepoxide (5 mg/kg, ip) shortened step-down latency of well-nourished rats, whereas it failed to do so in malnourished rats. Since well-nourished animals also became resistant to chlordiazepoxide when tested with a higher shock intensity, generating avoidance latencies comparable to those of malnourished animals, we conclude that the drug resistance induced by malnutrition may be secondary to enhanced pain sensitivity and/or reactivity.
Almeida
S S
SS
Departamento de Psicologia e Educação, Faculdade de Filosofia, Universidade de São Paulo, Ribirão Preto, Brasil.
De-Oliveira
L M
LM
Bichuette
M Z
MZ
Graeff
F G
FG
D000818:Animals; D001921:Brain / Q000503:physiopathology; D002707:Chlordiazepoxide / Q000494:pharmacology*; D004924:Escape Reaction / Q000187:drug effects*; D008297:Male; D009748:Nutrition Disorders / Q000503:physiopathology*; D011502:Protein-Energy Malnutrition / Q000503:physiopathology; D051381:Rats; D011919:Rats, Inbred Strains
D002707:Chlordiazepoxide