Background: gamma-Aminobutyric acid (GABA) is a known inhibitory neurotransmitter in the mammalian central nervous system, and homocysteine (Hcy) behaves as an antagonist for GABA(A) receptor. Although the properties and functions of GABA(A) receptors are well studied in mouse neural tissue, its presence and significance in non-neural tissue remains obscure. The aim of the present study was to examine the expression of GABA(A) receptor and its subunits in non-neural tissue.
Methods: The mice were analyzed. The presence of GABA(A) receptor and its subunits was evaluated using Western blot and reverse transcription polymerase chain reaction.
Results: We report that GABA(A) receptor protein is abundant in the renal medulla, cortex, heart, left ventricle, aorta and pancreas. Low levels of GABA(A) receptor protein were detected in the atria of the heart, right ventricle, lung and stomach. The mRNA protein expression of GABA(A) receptor subunit shows that alpha1, beta1, beta3 and gamma1 subunits are present only in brain. The mRNA protein expression levels of GABA(A) receptor alpha2, alpha6, beta2 and gamma3 subunits were highly expressed in brain compared to other tested tissue, while GABA(A) receptor gamma2 subunit was expressed only in brain and kidney. Treatment of microvascular endothelial cells with Hcy decreased GABA(A) receptor protein level, which was restored to its baseline level in the presence of GABA(A) receptor agonist, muscimol. The distribution of GABA(A) and GABA(B) receptors in wild type mice was determined and tissue-specific expression patterns were found showing that several receptor subtypes were also expressed in the central nervous system.
Conclusions: Hcy, a GABA(A) agonist, was found to decrease GABA(A) expression levels. These data enlarge knowledge on distribution of GABA receptors and give novel ideas of the effects of Hcy on different organs.
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http://dx.doi.org/10.1515/CCLM.2007.342 | DOI Listing |
J Med Chem
January 2025
Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, Copenhagen DK-2100, Denmark.
GABA receptors (GABARs) are the major elements of inhibitory neurotransmission in the central nervous system (CNS). They are established targets for regulation by endogenous brain neuroactive steroids (NASs) such as pregnanolone. However, the complexity of de novo synthesis of NAS derivatives has hindered attempts to circumvent the principal limitations of using endogenous NASs, including selectivity and limited oral bioavailability.
View Article and Find Full Text PDFIBRO Neurosci Rep
December 2024
Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Previous investigations have revealed the role of GABAergic and serotonergic systems in the modulation of pain behavior. This research aimed to examine the effects of intracerebroventricular (i.c.
View Article and Find Full Text PDFDrug Des Devel Ther
January 2025
Department of Anesthesiology, The Affiliated Hospital of Qingdao University, Qingdao, People's Republic of China.
Introduction: The mechanism of remimazolam, a benzodiazepine that activates γ-aminobutyric acid a (GABAa) receptors, in cerebral ischemia/reperfusion (I/R) injury is not well understood. Therefore, we explored whether remimazolam activates protein kinase B (AKT)/glycogen synthase kinase-3β (GSK-3β)/nuclear factor erythroid 2-related factor 2 (NRF2) to attenuate brain I/R injury in transcerebral I/R-injured rats and transoxygenic glucose deprivation/reperfusion (OGD/R)-injured SY5Y cells.
Material And Methods: Remimazolam was added at the beginning of cell and rat reperfusion, and the PI3K/AKT inhibitor LY294002 was added to inhibit the AKT/GSK-3β/NRF2 pathway 24 h before cellular OGD/R treatment and 30 min before rat brain I/R treatment.
Eur J Neurosci
January 2025
Université Grenoble Alpes, CNRS, LIPhy, Grenoble, France.
Staining brain slices with acetoxymethyl ester (AM) Ca dyes is a straightforward procedure to load multiple cells, and Fluo-4 is a commonly used high-affinity indicator due to its very large dynamic range. It has been shown that this dye preferentially stains glial cells, providing slow and large Ca transients, but it is questionable whether and at which temporal resolution it can also report Ca transients from neuronal cells. Here, by electrically stimulating mouse hippocampal slices, we resolved fast neuronal signals corresponding to 1%-3% maximal fluorescence changes.
View Article and Find Full Text PDFConditioned suppression is a useful paradigm for measuring learned avoidance. In most conditioned suppression studies, forward conditioning is used where a cue predicts an aversive stimulus. However, backward conditioning, in which an aversive stimulus predicts a cue, provides unique insights into learned avoidance due to its influence on both conditioned excitation and inhibition.
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