GABAA Receptor Availability in Relation to Cortical Excitability in Depressed and Healthy: A Positron Emission Tomography and Transcranial Magnetic Stimulation Study.

Autor:	Steinholtz L; Department of Medical Sciences, Psychiatry, Uppsala University, Uppsala, Sweden., Thörnblom E; Department of Medical Sciences, Psychiatry, Uppsala University, Uppsala, Sweden., Bodén R; Department of Medical Sciences, Psychiatry, Uppsala University, Uppsala, Sweden., Wall A; PET-Centre, Uppsala University Hospital, Uppsala, Sweden.; Department of Surgical Sciences, Nuclear medicine and PET, Uppsala University, Uppsala, Sweden., Axelson HW; Department of Medical Sciences, Clinical neurophysiology, Uppsala University, Uppsala, Sweden., Lubberink M; Department of Surgical Sciences, Nuclear medicine and PET, Uppsala University, Uppsala, Sweden.; Department of Medical Physics, Uppsala University Hospital, Uppsala, Sweden., Fällmar D; Department of Surgical Sciences, Neuroradiology, Uppsala University, Uppsala, Sweden., Persson J; Department of Medical Sciences, Psychiatry, Uppsala University, Uppsala, Sweden.
Jazyk:	angličtina
Zdroj:	Neuropsychobiology [Neuropsychobiology] 2024; Vol. 83 (1), pp. 17-27. Date of Electronic Publication: 2023 Dec 27.
DOI:	10.1159/000535512
Abstrakt:	Introduction: Gamma-aminobutyric acid (GABA) deficiency is suggested in depressive disorders, along with alterations in cortical excitability. However, whether these excitability changes are related to GABAA receptor availability is largely unknown. Our aim was to assess the correlation between these measures in depressed patients and healthy controls. Methods: Twenty-eight patients with a major depressive episode, measured before and after participating in a clinical trial with repetitive transcranial magnetic stimulation (TMS), and 15 controls underwent [11C]flumazenil positron emission tomography to assess GABAA receptor availability and paired pulse TMS (ppTMS) to evaluate cortical excitability. Both whole-brain voxel-wise GABAA receptor availability and mean values from left hand motor cortex and left paracentral lobule were correlated to the ppTMS outcomes: short-interval intracortical inhibition reflecting GABAA receptor activity, long-interval intracortical inhibition representing GABAB receptor activity, intracortical facilitation reflecting glutamate N-methyl-D-aspartate-receptor activity, as well as the resting motor threshold (rMT), considered a global measure of corticospinal excitability. Results: No significant differences in baseline GABAA receptor availability or cortical excitability were found between patients and controls. Additionally, no correlations were observed between baseline measurements of GABAA receptor availability and TMS outcomes. Changes in GABAA receptor availability in the hand motor cortex, between pre- and post-assessments, were inversely related to pre-post changes in hand rMT. Conclusion: We found that a change in GABAA receptor availability was inversely related to a change in rMT, suggesting a link between GABA deficiency and increased rMT previously observed in depressive episodes. The results highlight the complex mechanisms governing cortical excitability measures and offer new insight into their properties during the depressive state. (© 2023 The Author(s). Published by S. Karger AG, Basel.)
Databáze:	MEDLINE
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