Attenuation of restraint-induced behavioral deficits and serotonergic responses by stabilized rice bran in rats.

This study examined the effects of stabilized-rice bran (SRB) rich diet on responses to stress in rats. Standard rodent diet mixed with SRB in the ratio of 2:1 and 1:1 (w/w) was given for 6 weeks to test rats. Results showed that weekly cumulative food intakes smaller in SRB rich diet treated animals were normalized at the end of the treatment. Body weights decreased and exploratory activity in an open field increased in SRB rich diet treated animals. Learning and espatial memory monitored in the Morris water test was enhanced. An episode of 2 h restraint stress decreased food intake of SRB as well as normal diet treated animals. Deficits were smaller in SRB diet than normal diet treated animals. Exposure to 2 h restraint stress increased brain serotonin (5-hydroxytryptamine, 5-HT) metabolism. The increases were smaller in SRB rich than normal diet treated animals. A potential use of SRB in health and disease is discussed in the context of its antioxidant and serotonergic effect.