title: L-theanine partially counteracts caffeine-induced sleep disturbances in rats.
abstract: L-theanine has been reported to inhibit the excitatory effects of caffeine. The present study examined the effects of L-theanine on caffeine-induced sleep disturbances in rats. Rats received the following drug pairings: saline and saline (Control), 7.5 mg/kg caffeine and saline, or 7.5 mg/kg of caffeine followed by various doses of L-theanine (22.5, 37.5, 75, or 150 mg/kg). Vigilance states were divided into: wakefulness (W), transition to slow-wave sleep (tSWS), slow-wave sleep (SWS), and rapid-eye-movement sleep (REMS). Caffeine significantly increased the duration of W and decreased the duration of SWS and REMS compared to the Control. Although L-theanine failed to reverse the caffeine-induced W increase, at 22.5 and 37.5 mg/kg (but not at 75 and 150 mg/kg), it significantly reversed caffeine-induced decreases in SWS. In conclusion, low doses of L-theanine can partially reverse caffeine-induced reductions in SWS; however, effects of L-theanine on caffeine-induced insomnia do not appear to increase dose-dependently.
authors.affiliation: Department of Pharmacology, School of Medicine, Kyungpook National University, 2-101 Dongin-dong, Jung-gu Daegu 700-422, Republic of Korea.
authors.forename: Hwan-Soo
authors.initials: HS
authors.lastname: Jang
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Jung
authors.forename: Il-Sung
authors.initials: IS
authors.lastname: Jang
authors.forename: Kwang-Ho
authors.initials: KH
authors.lastname: Jang
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Kim
authors.forename: Jeoung-Hee
authors.initials: JH
authors.lastname: Ha
authors.forename: Kyoungho
authors.initials: K
authors.lastname: Suk
authors.forename: Maan-Gee
authors.initials: MG
authors.lastname: Lee
mesh_terms: D000818:Animals; D002110:Caffeine / Q000037:antagonists & inhibitors / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D005971:Glutamates / Q000494:pharmacology* / Q000627:therapeutic use; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012894:Sleep Stages / Q000187:drug effects; D012893:Sleep Wake Disorders / Q000139:chemically induced* / Q000503:physiopathology / Q000517:prevention & control*; D014851:Wakefulness / Q000187:drug effects
chemical_list: D005971:Glutamates; D002110:Caffeine; C026166:theanine