Individual differences in sucrose intake predict behavioral reactivity in rodent models of anxiety.

We have previously shown that individual differences in oral sucrose consumption are predictive of behavioral reactivity of rats in the elevated plus-maze (EPM). The present experiments were designed to replicate the EPM results and to extend them to another animal model of anxiety, the acoustic startle reflex (ASR) paradigm. In two experiments, sucrose consumption was assessed in separate groups of rats across eight daily 1-h feeding sessions. Animals were designated as either low (LSF) or high sucrose feeders (HSF) based on a median split of their sucrose intake on the final test day. Following this assay, animals were tested in the EPM in Experiment 1, and in the ASR paradigm in Experiment 2. Results from Experiment 1 replicated our previous findings and showed that the percentage of time spent on, and entries into, open arms was significantly lower in LSF than HSF. Further, results from Experiment 2 revealed a significantly augmented startle response to acoustic stimuli (94-108 dB SPL) in LSF compared to HSF. These data provide converging evidence to support the notion that individual differences in baseline levels of oral sucrose consumption are predictive of anxious behaviors in rats.