Meeting Abstract
Although the effect of stress on learning has been studied, we have limited information about how learning can induce physiological stress. We used the honeybee Apis mellifera to study the relationship between learning and stress given the learning protocols and behavioral/genetic analyses used in honeybee research. We used the Shuttle box protocol designed by Dinges et al. (2017) to simulate controllable (CS) and uncontrollable (US) stress. Animals assigned to the master condition (CS) had control as to when they were shocked while honeybees assigned to the yolk condition (US) had no control. After the behavioral phase, we dissected the honeybees’ brains, extracted RNA, and carried out RT-PCR to quantify the expression of the following genes: DH44, DLG, 5HT2A, DAR2, CAMK, HsP70, BRP, PKA, PUM and DH44R. ANOVA revealed a significant increase in the expression of the plasticity gene DAR2 in animals exposed to US and no statistically significant differences in other measures. However, we observed a tendency (increased gene expression) in DH44 and its receptor and in receptors 5HT2A and DAR2 in animals assigned to US. Post hoc power analysis revealed that sample sizes were too small to reach required statistical power. Our data suggest that honeybees are suitable for studying the biobehavioral mechanisms underlying the effect of learning on stress. Dopamine signaling via DAR2 might play a role in the neural adaptations associated with uncontrollable stress. For future research, we recommend analyzing gene expression in specific brain regions and extracting and dissecting the brain at different times of the day to study the interaction between gene expression and circadian rhythms.
