Thyroid hormones in the rat amygdala as common targets for antidepressant drugs, mood stabilizers, and sleep deprivation.
BACKGROUND
There have been repeated reports of antidepressant effects of thyroid hormones. In this study, we investigated whether antidepressant treatments enhance the concentrations of thyroid hormones in rat brain.


METHODS
Each of the groups of rats was treated for 14 days with one of the following: an antidepressant drug (desipramine, paroxetine, venlafaxine, or tianeptine); a mood stabilizer (lithium or carbamazepine); or 8 hours' partial sleep deprivation. Thyroid hormone concentrations were quantified in homogenates, nuclei, mitochondria, synaptosomes, myelin, and microsomes in 11 rat brain areas.


RESULTS
No drug effects were seen on nuclear triiodothyronine (T(3)) concentrations in any brain area. In the amygdala, all antidepressant drugs enhanced the levels of T(3) in the myelin fraction. Triiodothyronine molecules were identified in the myelin by immunogold labeling. Quantification of the major lipid components showed a selective decrease in cholesterol in the myelin of the amygdala after desipramine treatment. Desipramine induced an increase in protein concentrations, 3,5-diiodothyronine levels, and the activity of the mitochondrial enzyme succinate dehydrogenase in the mitochondria of the amygdala. Lithium, carbamazepine, and partial sleep deprivation raised the levels of T(3) in synaptosomes of the amygdala.


CONCLUSIONS
These results demonstrate that thyroid hormones in the amygdala are a common target of different antidepressant and mood-stabilizing therapies.
Pinna
Graziano
G
Department of Radiology and Nuclear Medicine, Universitätsklinikum Benjamin-Franklin, Free University of Berlin, Berlin, Germany.
Broedel
Oliver
O
Eravci
Murat
M
Stoltenburg-Didinger
Gisela
G
Plueckhan
Hanna
H
Fuxius
Sandra
S
Meinhold
Harald
H
Baumgartner
Andreas
A
D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases / Q000032:analysis; D027322:Amino Acid Transport System X-AG / Q000378:metabolism; D000679:Amygdala / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D000928:Antidepressive Agents / Q000494:pharmacology*; D018692:Antimanic Agents / Q000494:pharmacology*; D015153:Blotting, Western; D001923:Brain Chemistry; D017252:CD3 Complex / Q000378:metabolism; D002855:Chromatography, Thin Layer / Q000379:methods; D004247:DNA / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D008854:Microscopy, Electron; D009249:NADP / Q000032:analysis; D015388:Organelles / Q000378:metabolism / Q000648:ultrastructure; D050765:Qa-SNARE Proteins; D011863:Radioimmunoassay; D051381:Rats; D012892:Sleep Deprivation / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism / Q000648:ultrastructure; D013385:Succinate Dehydrogenase / Q000032:analysis; D016704:Synapsins / Q000378:metabolism; D013963:Thyroid Hormones / Q000378:metabolism*
D027322:Amino Acid Transport System X-AG; D000928:Antidepressive Agents; D018692:Antimanic Agents; D017252:CD3 Complex; D008565:Membrane Proteins; D050765:Qa-SNARE Proteins; D016704:Synapsins; D013963:Thyroid Hormones; D009249:NADP; D004247:DNA; D007770:L-Lactate Dehydrogenase; D013385:Succinate Dehydrogenase; D015087:2',3'-Cyclic-Nucleotide Phosphodiesterases