title: L-Theanine Improves Immunity by Altering TH2/TH1 Cytokine Balance, Brain Neurotransmitters, and Expression of Phospholipase C in Rat Hearts.
abstract: BACKGROUND This study aimed to investigate the regulatory effects of L-theanine on secretion of immune cytokines, hormones, and neurotransmitters, and mRNA expression of phospholipase C (PLC) in rats, and to explore its regulatory mechanism in immune function. MATERIAL AND METHODS Sixty-four Sprague-Dawley rats received daily intragastric infusion of different doses of L-theanine solution [0, 50 (LT), 200 (MT), and 400 (HT) mg/kg BW]. Cytokines, immunoglobulins, and hormones in the serum, neurotransmitters, and mRNA expression of PLC in the relevant tissues were assayed. RESULTS L-theanine administration increased the splenic organ index and decreased the contents of ILs-4/6/10 and the ratio of IL-4/IFN-γ in the serum. High-dose L-theanine administration increased the levels of dopamine and 5-hydroxytryptamine in the pituitary and hippocampus, resulting in decrease in corticosterone level in the serum. L-theanine administration decreased the mRNA expressions of PLC isomers in the liver and PLC-γ1 and PLC-δ1 in the spleen. Interestingly, mRNA expressions of PLC-β1 in the spleen and PLC isomers mRNA in the heart were up-regulated by L-theanine administration. CONCLUSIONS Administration of 400 mg/kg BWL-theanine improved immune function of the rats by increasing the splenic weight, altering the Th2/Th1 cytokine balance, decreasing the corticosterone level in the serum, elevating dopamine and 5-hydroxytryptamine in the brain, and regulating the mRNA expression of PLC isomers in the heart.
authors.affiliation: National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients from Botanicals, Provincial Co-Innovation Center for Utilization of Botanical Function Ingredients, Hunan Agricultural University, Changsha, Hunan, China (mainland).
authors.forename: Chengjian
authors.initials: C
authors.lastname: Li
authors.affiliation: National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients from Botanicals, Provincial Co-Innovation Center for Utilization of Botanical Function Ingredients, Hunan Agricultural University, Changsha, Hunan, China (mainland).
authors.forename: Haiou
authors.initials: H
authors.lastname: Tong
authors.affiliation: Key Laboratory of Agro-ecological Processes in Subtropical Region, Hunan Research Center of Livestock & Poultry Sciences, South-Central Experimental Station of Animal Nutrition and Feed Science in Ministry of Agriculture, Institute of Subtropical Agriculture, The Chinese Academy of Sciences, Changsha, Hunan, China (mainland).
authors.forename: Qiongxian
authors.initials: Q
authors.lastname: Yan
authors.affiliation: Key Laboratory of Agro-ecological Processes in Subtropical Region, Hunan Research Center of Livestock & Poultry Sciences, South-Central Experimental Station of Animal Nutrition and Feed Science in Ministry of Agriculture, Institute of Subtropical Agriculture, The Chinese Academy of Sciences, Changsha, Hunan, China (mainland).
authors.forename: Shaoxun
authors.initials: S
authors.lastname: Tang
authors.affiliation: National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients from Botanicals, Provincial Co-Innovation Center for Utilization of Botanical Function Ingredients, Hunan Agricultural University, Changsha, Hunan, China (mainland).
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Han
authors.affiliation: National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients from Botanicals, Provincial Co-Innovation Center for Utilization of Botanical Function Ingredients, Hunan Agricultural University, Changsha, Hunan, China (mainland).
authors.forename: Wenjun
authors.initials: W
authors.lastname: Xiao
authors.affiliation: National Research Center of Engineering Technology for Utilization of Botanical Functional Ingredients from Botanicals, Provincial Co-Innovation Center for Utilization of Botanical Function Ingredients, Hunan Agricultural University, Changsha, Hunan, China (mainland).
authors.forename: Zhiliang
authors.initials: Z
authors.lastname: Tan
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D016207:Cytokines / Q000097:blood*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D005971:Glutamates / Q000008:administration & dosage / Q000494:pharmacology*; D007109:Immunity / Q000187:drug effects*; D008297:Male; D009206:Myocardium / Q000201:enzymology*; D018377:Neurotransmitter Agents / Q000378:metabolism*; D009928:Organ Specificity / Q000187:drug effects; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D018417:Th1 Cells / Q000187:drug effects / Q000276:immunology*; D018418:Th2 Cells / Q000187:drug effects / Q000276:immunology*; D010738:Type C Phospholipases / Q000235:genetics / Q000378:metabolism*
chemical_list: D016207:Cytokines; D005971:Glutamates; D018377:Neurotransmitter Agents; C026166:theanine; D010738:Type C Phospholipases