UNDERNUTRITION DURING SUCKLING HAS NO EFFECT ON THE RAT LOCOMOTOR-ACTIVITY RESPONSE TO CAFFEINE

It is known that early malnutrition causes hyposensitivity to serotone rgic, gabaergic, catecholaminergic and opioid stimulation. In the pres ent study, we determined whether adult rats undernourished during suck ling presented an altered response to caffeine administration in a loc omotor activity test. Rats were undernourished during suckling by feed ing their dams a 7% casein diet. During the same period, well-nourishe d dams were fed a 28% casein diet. Animals (90-100 days of age) were h abituated to the apparatus. Thereafter, a dose-response curve for caff eine (2.5, 10.0, 20.0, 40.0 and 120.0-mu-mol/kg, ip) was determined. D uring handling sessions, undernourished rats presented lower activity scores than well-nourished animals (average values: 44.2 +/- 16.4 vs 5 7.9 +/- 15.4). Well-nourished and undernourished rats responded in a s imilar way to caffeine administration by increasing the locomotor acti vity in a dose-dependent manner. Although undernourished animals prese nt an altered sensitivity to various neuropharmacological compounds, t he present results indicate that their sensitivity to the locomotor-ac tivating effect of caffeine is the same as that of rats well-nourished during suckling.