Sub-chronic effects of s-limonene on brain neurotransmitter levels and behavior of rats.
The present study was designed to gain insight into the effects of s-limonene on the brain after 1-wk administration. For this purpose, neurotransmitters such as dopamine (DA), serotonin (5-HT), gamma-aminobutyric acid (GABA), glutamic acid (Glu) and some of their metabolites (DOPAC and 5-HIAA) were determined by HPLC-ECD and amino acid analyzer after 1-wk administration of s-limonene of different concentrations (0, 5, 25, 50 mg/kg). Significant changes, such as GABA, 5-hydroxyindoleacetic acid (5-HIAA) and 5-HT, were confirmed. At the same time, basal hypothalamic-pituitary-adrenal (HPA) activity after 1-wk administration of s-limonene was evaluated by corticosterone. Considering the increment of GABA and the changes of other neurotransmitters, anti-stress effects after 1-wk administration were observed. The experimental results showed that s-limonene could inhibit HPA activity under physical stress and this anti-stress effect of s-limonene may act through the GABA(A) receptor.
Zhou
Wenjun
W
Laboratory of Nutritional Biochemistry, Global COE Program in the 21st Century, Graduate School of Nutritional and Environmental Sciences, The University of Shizuoka, Yada, Suruga, Shizuoka, Japan.
Yoshioka
Miyuki
M
Yokogoshi
Hidehiko
H
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D001921:Brain / Q000187:drug effects* / Q000378:metabolism; D003345:Corticosterone; D053138:Cyclohexenes / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism; D018755:GABA Agonists / Q000494:pharmacology; D018698:Glutamic Acid / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects; D000077222:Limonene; D008297:Male; D018377:Neurotransmitter Agents / Q000378:metabolism*; D009822:Oils, Volatile / Q000494:pharmacology; D010913:Pituitary-Adrenal System / Q000187:drug effects; D010936:Plant Extracts / Q000494:pharmacology*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D012701:Serotonin / Q000378:metabolism; D013312:Stress, Physiological / Q000187:drug effects*; D013729:Terpenes / Q000494:pharmacology*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism*
D053138:Cyclohexenes; D018755:GABA Agonists; D018377:Neurotransmitter Agents; D009822:Oils, Volatile; D010936:Plant Extracts; D013729:Terpenes; D012701:Serotonin; D018698:Glutamic Acid; D005680:gamma-Aminobutyric Acid; D000077222:Limonene; D004298:Dopamine; D003345:Corticosterone