Undernutrition during suckling has no effect on the rat locomotor activity response to caffeine

It is known that early malnutrition causes hyposensitivity to serotonergic, gabaergic, catecholaminergic and opioid stimulation. In the present study, we determined whether adult rats undernourished during suckling presented an altered response to caffeine administration in a locomotor activity test. Rats were undernourished during suckling by feeding their dams a 7% casein diet. During the same period, well-nourished dams were fed a 28% casein diet. Animals (90-100 days of age) were habituated to the apparatus. Thereafter, a dose-response curve for caffeine (2.5, 10.0, 20.0, 40.0 and 120.0 mumol/kg, ip) was determined. During handling sessions, undernourished rats presented lower activity scores than well-nourished animals (average values: 44.2 +/- 16.4 vs 57.9 +/- 15.4). Well-nourished and undernourished rats responded in a similar way to caffeine administration by increasing the locomotor activity in a dose-dependent manner. Although undernourished animals present an altered sensitivity to various neuropharmacological compounds, the present results indicate that their sensitivity to the locomotor-activating effect of caffeine is the same as that of rats well-nourished during suckling.