The impact of chronic imipramine treatment on amino acid concentrations in the hippocampus of mice.
The relationship between antidepressants and monoamine concentrations in the brain has been well investigated, but few studies have investigated the relationship between antidepressants and amino acid concentrations in the brain. The purpose of the present study was therefore to investigate the effect of the chronic antidepressant imipramine on amino acid and monoamine concentrations in the mouse brain and plasma. Chronic imipramine treatment decreased the concentration of 5-hydroxyindoleaceticacid/5-hydroxytryptamine in the cerebral cortex and increased that of norepinephrine (NE) in the hippocampus. Since these changes were conspicuous effects of the antidepressant, we concluded that imipramine acts on the central nervous system. No change in amino acid concentrations in plasma was induced by chronic imipramine treatment, but several changes were confirmed in the cerebral cortex, the hypothalamus and the hippocampus. Chronic imipramine treatment caused increases in L-methionine, L-tyrosine, and L-lysine in the cerebral cortex, and an increase in L-aspartate in the hypothalamus. Contrary to this, the concentrations of L-aspartate, L-serine, L-asparagine, glycine, L-glutamine, gamma-aminobutyric acid, L-threonine, L-arginine, L-proline, L-valine, and L-methionine in the hippocampus were decreased by chronic imipramine treatment. The present results demonstrate that the metabolism of several amino acids in the brain, but not of those in plasma, was altered by chronic imipramine treatment. The findings in the present study may help to further elucidate the relationship between amino acids and the effects and side effects of antidepressants.
Laboratory of Regulation in Metabolism and Behavior, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan.
Mao
M
Nagasawa
Tatsuro
T
Murakami
Shozo
S
Tomonaga
Mitsuhiro
M
Furuse
D000596:Amino Acids / Q000097:blood / Q000378:metabolism*; D000818:Animals; D000929:Antidepressive Agents, Tricyclic / Q000494:pharmacology*; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D001923:Brain Chemistry / Q000187:drug effects / Q000502:physiology; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism; D003865:Major Depressive Disorder / Q000188:drug therapy / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006624:Hippocampus / Q000187:drug effects* / Q000378:metabolism*; D006897:Hydroxyindoleacetic Acid / Q000378:metabolism; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D007099:Imipramine / Q000494:pharmacology*; D051379:Mice; D008813:Mice, Inbred ICR; D009638:Norepinephrine / Q000378:metabolism; D011897:Random Allocation; D012701:Serotonin / Q000378:metabolism
D000596:Amino Acids; D000929:Antidepressive Agents, Tricyclic; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D007099:Imipramine; D009638:Norepinephrine