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Raitsin S, Tong J, Kish S, Xu X, Magomedova L, Cummins C, Andreazza AC, Scola G, Baker G, Meyer JH. Subchronic glucocorticoids, glutathione depletion and a postpartum model elevate monoamine oxidase a activity in the prefrontal cortex of rats. Brain Res 2017; 1666:1-10. [PMID: 28435083 DOI: 10.1016/j.brainres.2017.03.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/27/2017] [Accepted: 03/29/2017] [Indexed: 10/19/2022]
Abstract
Recent human brain imaging studies implicate dysregulation of monoamine oxidase-A (MAO-A), in particular in the prefrontal cortex (PFC) and anterior cingulate cortex (ACC), in the development of major depressive disorder (MDD). This study investigates the influence of four alterations underlying important pathologies of MDD, namely, chronic elevation of glucocorticoid levels, glutathione depletion, changes in female gonadal sex hormones and serotonin concentration fluctuation, on MAO-A and MAO-B activities in rats. Young adult rats exposed chronically to the synthetic glucocorticoid dexamethasone at 0, 0.05, 0.5, and 2.0mg/kg/day (osmotic minipumps) for eight days showed significant dose-dependent increases in activities of MAO-A in PFC (+17%, p<0.001) and ACC (+9%, p<0.01) and MAO-B in PFC (+14%, p<0.001) and increased serotonin turnover in the PFC (+31%, p<0.01), not accounted for by dexamethasone-induced changes in serotonin levels, since neither serotonin depletion nor supplementation affected MAO-A activity. Sub-acute depletion of the major antioxidant glutathione by diethyl maleate (5mmol/kg, i.p.) for three days, which resulted in a 36% loss of glutathione in PFC (p=0.0005), modestly, but significantly, elevated activities of MAO-A in PFC and MAO-B in PFC, ACC and hippocampus (+6-9%, p<0.05). Changes in estrogen and progesterone representing pseudopregnancy were associated with significantly elevated MAO-A activity in the ACC day 4-7 postpartum (10-18%, p<0.05 to p<0.0001) but not the PFC or hippocampus. Hence, our study provides data in support of strategies targeting glucocorticoid and glutathione systems, as well as changes in female sex hormones for normalization of MAO-A activities and thus treatment of mood disorders.
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Affiliation(s)
- Sofia Raitsin
- Research Imaging Centre and Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Junchao Tong
- Human Brain Laboratory, Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada
| | - Stephen Kish
- Human Brain Laboratory, Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada
| | - Xin Xu
- Research Imaging Centre and Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada
| | - Lilia Magomedova
- Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ontario M5S 3M2, Canada
| | - Carolyn Cummins
- Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ontario M5S 3M2, Canada
| | - Ana C Andreazza
- Departments of Psychiatry and Pharmacology and Toxicology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Gustavo Scola
- Departments of Psychiatry and Pharmacology and Toxicology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada; Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Glen Baker
- Neuroscience and Mental Health Institute and Department of Psychiatry (NRU), University of Alberta, 8440 112 Street NW, Edmonton, Alberta T6G 2G3, Canada
| | - Jeffrey H Meyer
- Research Imaging Centre and Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada; Department of Psychiatry and Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.
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Leung TK, Lai JC, Lim L. Type A and type B monoamine oxidase activities in rat brain and liver mitochondria: a comparison of their properties using the non-ionic detergent Triton X-100. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. C: COMPARATIVE PHARMACOLOGY 1982; 71:219-22. [PMID: 6122536 DOI: 10.1016/0306-4492(82)90040-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
1. The effects of the non-ionic detergent Triton X-100 on the heterogeneity of monoamine oxidase activities were studied and compared in synaptic (fractions SM and SM2) and non-synaptic (fraction M) brain mitochondria and liver mitochondria. 2. Triton X-100 inhibited type A and type B monoamine oxidase activities in all four mitochondrial fractions in a concentration-dependent manner. Liver mitochondrial enzymatic activities were much more sensitive to this inhibition than those of brain mitochondria. The activities in the SM fraction of synaptic brain mitochondria were the least susceptible. 3. In all four mitochondrial fractions, type A activities were more sensitive to inhibition than type B activities. 4. These results suggest that the membrane micro-environment around the enzyme molecules in situ may be important in the functional expression of the activity of the enzyme.
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