INDIVIDUAL-DIFFERENCES IN SUCROSE INTAKE PREDICT BEHAVIORAL REACTIVITY IN RODENT MODELS OF ANXIETY

We have previously shown that individual differences in oral sucrose c onsumption are predictive of behavioral reactivity of rats in the elev ated plus-maze (EPM). The present experiments were designed to replica te the EPM results and to extend them to another animal model of anxie ty, the acoustic startle reflex (ASR) paradigm. In two experiments, su crose consumption was assessed in separate groups of rats across eight daily 1-h feeding sessions. Animals were designated as either low (LS F) or high sucrose feeders (HSF) based on a median split of their sucr ose intake on the final test day. Following this assay, animals were t ested in the EPM in Experiment 1, and in the ASR paradigm in Experimen t 2. Results from Experiment 1 replicated our previous findings and sh owed that the percentage of time spent on, and entries into, open arms was significantly lower in LSF than HSF. Further, results from Experi ment 2 revealed a significantly augmented startle response to acoustic stimuli (94-108 dB SPL) in LSF compared to HSF. These data provide co nverging evidence to support the notion that individual differences in baseline levels of oral sucrose consumption are predictive of anxious behaviors in rats. (C) 1998 Elsevier Science Inc.