In the mammalian CNS, the expression of neuronal gap junction protein, connexin 36 (Cx36), increases during the first 2 weeks of postnatal development and then decreases during the following 2 weeks. Recently we showed that the developmental increase in Cx36 expression is augmented by chronic (2 weeks) activation of group II metabotropic glutamate receptors (mGluR), prevented by chronic receptor inactivation, and the receptor-dependent increase in Cx36 expression is regulated via transcriptional control of the Cx36 gene activity. We demonstrate here that acute (60 min) activation of group II mGluRs in developing cortical neuronal cultures causes transient increase in Cx36 protein expression with decrease during the following 24h. However, there is no change in Cx36 mRNA expression. In addition, the data indicate that transient increase in Cx36 expression is due to new protein synthesis. The results suggest that, during development, acute activation of group II mGluRs causes up-regulation of Cx36 via post-transcriptional mechanisms. However, if the receptor activation is sustained, transcriptional activation of the Cx36 gene occurs.
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http://dx.doi.org/10.1016/j.neulet.2012.01.075 | DOI Listing |
Biology (Basel)
June 2024
Departamento de Biología Celular y Tisular, Facultad de Medicina, UNAM, Mexico City 04510, Mexico.
Unlabelled: Glucotoxicity may exert its deleterious effects on pancreatic β-cell function via a myriad of mechanisms, leading to impaired insulin secretion and, eventually, type 2 diabetes. β-cell communication requires gap junction channels to be present among these cells. Gap junctions are constituted by transmembrane proteins of the connexins (Cxs) family.
View Article and Find Full Text PDFMath Biosci
August 2024
Department of Mathematics, Erzurum Technical University, Erzurum, Turkey; Department of Cardiology, Erasmus University Medical Center, Rotterdam, The Netherlands. Electronic address:
Gain of function mutations in the pore forming Kir6 subunits of the ATP sensitive K channels (K(ATP) channels) of pancreatic β-cells are the major cause of neonatal diabetes in humans. In this study, we show that in insulin secreting mouse β-cell lines, gain of function mutations in Kir6.1 result in a significant connexin36 (Cx36) overexpression, which form gap junctional connections and mediate electrical coupling between β-cells within pancreatic islets.
View Article and Find Full Text PDFInt J Mol Sci
May 2024
Department of Pathophysiology, University of Split School of Medicine, 21000 Split, Croatia.
Gap junctions (GJs) are important in the regulation of cell growth, morphology, differentiation and migration. However, recently, more attention has been paid to their role in the pathogenesis of different diseases as well as tumorigenesis, invasion and metastases. The expression pattern and possible role of connexins (Cxs), as major GJ proteins, under both physiological and pathological conditions in the adrenal gland, were evaluated in this review.
View Article and Find Full Text PDFExp Eye Res
April 2024
School of Optometry, The Hong Kong Polytechnic University, Kowloon, Hong Kong; Centre for Eye and Vision Research (CEVR), 17W Hong Kong Science Park, Hong Kong; Research Centre for SHARP Vision (RCSV), The Hong Kong Polytechnic University, Hong Kong; Hong Kong Polytechnic University Shenzhen Research Institute, Shenzhen, China. Electronic address:
Myopia and astigmatism are two primary types of refractive errors characterized by inaccurate focusing images on the retina. This study aimed to investigate the response characteristics of Retinal Ganglion Cells (RGCs), represented by alpha (α) RGCs, when exposed to focused, simulated spherically defocused images and astigmatically defocused images projected onto mouse retinas. Negative pressure was applied to stretch the soma of RGC in vitro to simulate myopia using a 7-8 μm diameter glass microelectrode, resulting in a 5% increase in the cell's diameter.
View Article and Find Full Text PDFEur J Neurosci
April 2024
Institute of Neurobiology, Center of Brain, Behaviour and Metabolism, Marie-Curie-Strasse, University of Lübeck, Lübeck, Germany.
The circadian clock orchestrates many physiological and behavioural rhythms in mammals with 24-h periodicity, through a hierarchical organisation, with the central clock located in the suprachiasmatic nucleus (SCN) in the hypothalamus. The circuits of the SCN generate circadian rhythms with precision, relying on intrinsic coupling mechanisms, for example, neurotransmitters like arginine vasopressin (AVP), vasoactive intestinal peptide (VIP), neuronal gamma-aminobutyric acid (GABA) signalling and astrocytes connected by gap junctions composed of connexins (Cx). In female rodents, the presence of estrogen receptors (ERs) in the dorsal SCN suggests an influence of estrogen (E2) on the circuit timekeeping that could regulate circadian rhythm and coupling.
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