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Alkadhi KA. Synaptic Plasticity and Cognitive Ability in Experimental Adult-Onset Hypothyroidism. J Pharmacol Exp Ther 2024; 389:150-162. [PMID: 38508752 DOI: 10.1124/jpet.123.001887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 02/05/2024] [Accepted: 02/20/2024] [Indexed: 03/22/2024] Open
Abstract
Adult-onset hypothyroidism impairs normal brain function. Research on animal models of hypothyroidism has revealed critical information on how deficiency of thyroid hormones impacts the electrophysiological and molecular functions of the brain, which leads to the well known cognitive impairment in untreated hypothyroid patients. Currently, such information can only be obtained from experiments on animal models of hypothyroidism. This review summarizes important research findings that pertain to understanding the clinical cognitive consequences of hypothyroidism, which will provide a better guiding path for therapy of hypothyroidism. SIGNIFICANCE STATEMENT: Cognitive impairment occurs during adult-onset hypothyroidism in both humans and animal models. Findings from animal studies validate clinical findings showing impaired long-term potentiation, decreased CaMKII, and increased calcineurin. Such findings can only be gleaned from animal experiments to show how hypothyroidism produces clinical symptoms.
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Affiliation(s)
- Karim A Alkadhi
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas
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Barros CFD, Guarnieri LDO, Mansk LMZ, Secio-Silva A, Emrich F, Ferreira M, Silva WND, Peliciari-Garcia RA, Pereira GS, Bargi-Souza P. The memory impairment by hypothyroidism in mice is dependent on time-of-day and sex. Behav Brain Res 2023; 452:114595. [PMID: 37482305 DOI: 10.1016/j.bbr.2023.114595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Revised: 07/18/2023] [Accepted: 07/20/2023] [Indexed: 07/25/2023]
Abstract
Hypothyroidism is an endocrine-metabolic disorder, and as such it compromises a wide range of physiological functions. Memory deficits and, the most recently described, circadian rhythm disruption are among the impairments caused by thyroid dysfunctions. However, although highly likely, there is no evidence connecting these two effects of hypothyroidism. Here, we hypothesized the time-of-day interferes with the memory deficit caused by hypothyroidism. C57BL/6 J mice from both sexes were subjected to novel object recognition (NOR) task during the rest and active phases, corresponding to ZT 2-4 and 14-16, respectively (ZT: Zeitgeber time; ZT 0: lights on at 07:00 am). First, we showed that neither sex nor ZT altered object recognition memory (ORM) in euthyroid mice. Next, animals were divided into control (euthyroid) and hypothyroid [induced with methimazole (0.01%) and perchlorate (0.1%) treatment in the drinking water for 21 days] groups. Under euthyroid conditions, male and female mice recognized the novel object regardless of the time-of-day. However, hypothyroidism impaired ORM at rest phase (ZT 2-4) in both sexes. Surprisingly, in the active phase (ZT 14-16), the hypothyroid males performed the NOR, though a longer time to execute the task was required. In contrast, female hypothyroid mice showed a greater impairment in ORM. Our results suggest that hypothyroidism may disrupt the circadian rhythm in brain areas related to mnemonic processes since in euthyroid condition ORM is not affected by the time-of-day. Furthermore, our findings in an animal model indicate a pronounced deleterious effect of hypothyroidism in women.
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Affiliation(s)
- Carolina Fonseca de Barros
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Leonardo de Oliveira Guarnieri
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil; Centro de Tecnologia e Pesquisa em Magneto Ressonância, Programa de Pós-Graduação em Engenharia Elétrica, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Lara Monteiro Zanetti Mansk
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Ayla Secio-Silva
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Felipe Emrich
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Maíza Ferreira
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Walison Nunes da Silva
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil
| | - Rodrigo Antonio Peliciari-Garcia
- Departamento de Ciências Biológicas, Setor de Morfofisiologia e Patologia, Universidade Federal de São Paulo (UNIFESP), Diadema, SP, Brazil
| | - Grace Schenatto Pereira
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil.
| | - Paula Bargi-Souza
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG, Brazil.
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Tan B, Dursun N, Süer C. Comparison of the subsequent LTP in hippocampal synapses primed by low frequency stimulations ranging from 0.5 to 5 Hz: An in vivo study. Neurosci Lett 2022; 767:136311. [PMID: 34743896 DOI: 10.1016/j.neulet.2021.136311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 10/22/2021] [Accepted: 10/23/2021] [Indexed: 11/29/2022]
Abstract
According to the Bienenstock,Cooper, andMunro's (BCM) model, the level of afferent activity regulates the point of crossover from long-term depression (LTD) to long-term potentiation (LTP) of the active synapses. Although experimental results from the hippocampus and visual cortex have supported the BCM theory, it remains unclear whether previous activity of synapses regulates the output of neuron populations in vivo, as expected from the theory. In the present study, we studied the effects of priming stimulations at different frequencies (LFS, 0.5, 1, 2 and 5 Hz) on the magnitude of LTP at synaptic and somatic levels in the dentate gyrus of hippocampal formation. LTP in the dentate gyrus (DG) of LFS-primed or unprimed hippocampal formation was induced by delivering of tetanic stimulation to the perforant pathway (PP) in anesthetized rats. The field excitatory postsynaptic potential (fEPSP) slope and the population spike (PS) amplitude were evaluated to measure the magnitude of LTP. 1 Hz- and 5 Hz- (not 0.5 Hz and 2 Hz) stimulation of the PP led to an early LTD of fEPSP. The LTP of fEPSP was completely inhibited by previously delivering 0.5 Hz and 2 Hz LFS, but instead converted to LTD by 1 Hz LFS. However, none of the frequencies used was able to inhibit the LTP of PS. These results suggest that temporal dynamics which are critical to determine the direction of synaptic plasticity has no impact on the plasticity of neuronal output. We concluded that it is needed to explain why neuronal output does not behave within the framework of the BCM theory.
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Affiliation(s)
- Burak Tan
- Erciyes University, School of Medicine, Department of Physiology, Kayseri, Turkey.
| | - Nurcan Dursun
- Erciyes University, School of Medicine, Department of Physiology, Kayseri, Turkey
| | - Cem Süer
- Erciyes University, School of Medicine, Department of Physiology, Kayseri, Turkey
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Głombik K, Detka J, Budziszewska B. Venlafaxine and L-Thyroxine Treatment Combination: Impact on Metabolic and Synaptic Plasticity Changes in an Animal Model of Coexisting Depression and Hypothyroidism. Cells 2021; 10:cells10061394. [PMID: 34198731 PMCID: PMC8227539 DOI: 10.3390/cells10061394] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/31/2021] [Accepted: 06/02/2021] [Indexed: 12/23/2022] Open
Abstract
The clinical effectiveness of supportive therapy with thyroid hormones in drug-resistant depression is well-known; however, the mechanisms of action of these hormones in the adult brain have not been fully elucidated to date. We determined the effects of venlafaxine and/or L-thyroxine on metabolic parameters and markers involved in the regulation of synaptic plasticity and cell damage in an animal model of coexisting depression and hypothyroidism, namely, Wistar Kyoto rats treated with propylthiouracil. In this model, in relation to the depression model itself, the glycolysis process in the brain was weakened, and a reduction in pyruvate dehydrogenase in the frontal cortex was normalized only by the combined treatment with L-thyroxine and venlafaxine, whereas changes in pyruvate and lactate levels were affected by all applied therapies. None of the drugs improved the decrease in the expression of mitochondrial respiratory chain enzymes. No intensification of glucocorticoid action was shown, while an unfavorable change caused by the lack of thyroid hormones was an increase in the caspase-1 level, which was not reversed by venlafaxine alone. The results indicated that the combined administration of drugs was more effective in normalizing glycolysis and the transition to the Krebs cycle than the use of venlafaxine or L-thyroxine alone.
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Affiliation(s)
- Katarzyna Głombik
- Laboratory of Immunoendocrinology, Department of Experimental Neuroendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland; (J.D.); (B.B.)
- Correspondence: ; Tel.: +48-12-662-33-94
| | - Jan Detka
- Laboratory of Immunoendocrinology, Department of Experimental Neuroendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland; (J.D.); (B.B.)
| | - Bogusława Budziszewska
- Laboratory of Immunoendocrinology, Department of Experimental Neuroendocrinology, Maj Institute of Pharmacology, Polish Academy of Sciences, Smętna 12, 31-343 Kraków, Poland; (J.D.); (B.B.)
- Department of Biochemical Toxicology, Medical College, Jagiellonian University, Medyczna 9, 30-688 Kraków, Poland
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Contribution of Hypothyroidism to Cognitive Impairment and Hippocampal Synaptic Plasticity Regulation in an Animal Model of Depression. Int J Mol Sci 2021; 22:ijms22041599. [PMID: 33562494 PMCID: PMC7915890 DOI: 10.3390/ijms22041599] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 01/29/2021] [Accepted: 02/03/2021] [Indexed: 12/11/2022] Open
Abstract
The role that thyroid hormone deficiency plays in depression and synaptic plasticity in adults has only begun to be elucidated. This paper analyzes the possible link between depression and hypothyroidism in cognitive function alterations, using Wistar–Kyoto (WKY—an animal model of depression) rats and control Wistar rats under standard and thyroid hormone deficiency conditions (propylthiouracil administration—PTU). A weakening of memory processes in the WKY rats is shown behaviorally, and in the reduction of long-term potentiation (LTP) in the dentate gyrus (DG) and CA1 hippocampal regions. PTU administration decreased LTP and increased basal excitatory transmission in the DG in Wistar rats. A decrease in short-term synaptic plasticity is shown by the paired-pulse ratio measurement, occurring during hypothyroidism in DG and CA1 in WKY rats. Differences between the strains may result from decreases in the p-CaMKII, p-AKT, and the level of acetylcholine, while in the case of the co-occurrence of depression and hypothyroidism, an increase in the p-ERK1-MAP seemed to be important. Obtained results show that thyroid hormones are less involved in the inhibition of glutamate release and/or excitability of the postsynaptic neurons in WKY rats, which may indicate a lower sensitivity of the hippocampus to the action of thyroid hormones in depression.
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