Analysis of the Sensory and Hedonic Impacts of Sweet and Bitter Tastes in Perinatally Underfed Rats

Abstract

Newborn rats discriminate tastes and generate gustofacial response (GFR) because the neuronal substrate is already operating. The oral application of sucrose or quinine hydrochloride produces a specific GFR. We analyzed the effects of perinatal undernutrition on the GFR development of rats at two cue concentrations. In the undernourished group, pregnant dams received different percentages of a balance diet. After birth, prenatally underfed pups continue the undernourishment by remaining for 12 h with a foster dam, and for 12 h with a nipple-ligated mother. Cues were presented as a single droplet of sucrose, sodium chloride, or quinine at low or high concentrations onto the lips at postnatal days (PDs) 1 and 3, and mouth-opening (MOF) and lip-licking frequencies (LLF) were noted. On PD 1 the undernourished group showed smaller MOF increases in response to low salt and quinine stimuli than the controls but no differences at high concentrations. On PD 3, both low and high concentrations of the sucrose and quinine cues significantly increased the MOF in the underfed compared to the control group. Low but not high salt decreased LLF on PD1 in the underfed compared to the control group. On PD 3 the undernourished pups showed significant increases of LLF with low quinine compared with the control rats, but the reverse was observed with high quinine. These data suggest that perinatal undernutrition affects the development of the sensory and hedonic aspects of taste causing changes in GFR expression.