Prolonged treatment with vitamins C and E separately and together decreases anxiety-related open-field behavior and acoustic startle in hooded rats.

Adult male and female hooded rats (about 110 days old) consumed vitamins C and E separately and combined together in their drinking water and were assessed for anxiety approximately 50 and then 80 days later in an open field and an acoustic startle apparatus. They were tested when 160+ days old, and then again at 190+ days. For both testing ages combined, the vitamins and their combination increased open-field ambulation and occupancy of the four center squares of the apparatus, while also accordingly decreasing occupancy of the four corners. Treatment with vitamins C and E separately and combined together also decreased acoustic startle amplitude. While there were several significant overall sex and testing age differences, there was no evidence that the vitamin treatment effects were dependent on the operation of either variable. There was also no evidence of synergism between vitamins C and E in their effects. It was suggested that decreases in anxiety produced by the vitamins may have arisen from their antioxidant properties, attenuation of cortisol activity or some as yet undetermined effects on anxiety-related brain structures and neurotransmitters.