More new research on Theanine (found in FRL Reboot) showing it reduces stress during confrontation...
Exp Physiol. 2012 Jun 15. [Epub ahead of print]
Ingestion of theanine, an amino acid in tea, suppresses psychosocial stress in mice.
Unno K, Iguchi K, Tanida N, Fujitani K, Takamori N, Yamamoto H, Ishii N, Nagano H, Nagashima T, Hara A, Shimoi K, Hoshino M.
University of Shizuoka.
The anti-stress effect of theanine (γ-glutamylethylamide), an amino acid in tea, was investigated using mice that were psychosocially stressed from a conflict among male mice under confrontational housing. Two male mice were housed in the same cage separated with a partition to establish a territorial imperative. Then, the partition was removed and mice were co-housed confrontationally (confrontational housing). As a marker for stress-response, changes in the adrenal gland were studied in comparison to group-housed control mice (6 mice in a cage). Significant adrenal hypertrophy was observed in mice under confrontational housing, which was developed in 24 h and persisted for at least 1 week. The cell size in the zona fasciculata of the adrenal gland, from which glucocorticoid is mainly secreted, increased (ca. 1.11 times) in mice under confrontational housing, which was accompanied by the flattened diurnal rhythm of corticosterone and ACTH in blood. The ingestion of theanine (>5 μg/ml) prior to confrontational housing significantly suppressed adrenal hypertrophy. An anti-depressant paroxetin similarly suppressed adrenal hypertrophy in mice under confrontational housing. In mice that ingested theanine, behavioral depression was also suppressed and a diurnal rhythm of corticosterone and ACTH was observed, even when mice were under confrontational housing. Furthermore, the daily dose of theanine (40 μg/ml) blocked the counteracting effects of caffeine (30 μg/ml) and catechin (200 μg/ml). The present study demonstrated that theanine prevents and relieves psychosocial stress through the modulation of HPA axis activity.
PMID: 22707502 [PubMed - as supplied by publisher]