The existence of electrical communication among pyramidal cells (PCs) in the adult cortex has been debated by neuroscientists for several decades. Gap junctions (GJs) among cortical interneurons have been well documented experimentally and their functional roles have been proposed by both computational neuroscientists and experimentalists alike. Experimental evidence for similar junctions among pyramidal cells in the cortex, however, has remained elusive due to the apparent rarity of these couplings among neurons. In this work, we develop a neuronal network model that includes observed probabilities and strengths of electrotonic coupling between PCs and gap-junction coupling among interneurons, in addition to realistic synaptic connectivity among both populations. We use this network model to investigate the effect of electrotonic coupling between PCs on network behavior with the goal of theoretically addressing this controversy of existence and purpose of electrotonically coupled PCs in the cortex.
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http://dx.doi.org/10.1007/s10827-020-00762-5 | DOI Listing |
Background: Patients with arrhythmogenic cardiomyopathy (ACM) due to pathogenic variants in , the gene for the desmosomal protein plakophilin-2, are being enrolled in gene therapy trials designed to replace the defective allele via adeno-associated viral (AAV) transduction of cardiac myocytes. Evidence from experimental systems and patients indicates that ventricular myocytes in ACM have greatly reduced electrical coupling at gap junctions and reduced Na current density. In previous AAV gene therapy trials, <50% of ventricular myocytes have generally been transduced.
View Article and Find Full Text PDFJ Am Heart Assoc
January 2025
Graduate Program in Translational Biology Medicine and Health, Virginia Tech Roanoke VA USA.
Background: Previous studies suggest the relationship between activation time (AT) and action potential duration (APD) in the heart is dependent on electrotonic coupling, but this has not been directly tested. This study assessed whether acute changes in electrical coupling, or other determinants of conduction or repolarization, modulate APD heterogeneity.
Methods And Results: Langendorff-perfused guinea pig hearts were epicardially paced and optically mapped after treatment with the gap junction uncoupler carbenoxolone, ephaptic uncoupler mannitol, ephaptic enhancer dextran 2MDa, sodium channel inhibitor flecainide, or rapid component of the delayed rectifier potassium channel inhibitor E4031.
Nano Lett
October 2024
Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States.
Dis Model Mech
August 2024
Victor Chang Cardiac Research Institute, Sydney, 2010, Australia.
Hypertrophic cardiomyopathy (HCM) is an inherited heart muscle disease that is characterised by left ventricular wall thickening, cardiomyocyte disarray and fibrosis, and is associated with arrhythmias, heart failure and sudden death. However, it is unclear to what extent the electrophysiological disturbances that lead to sudden death occur secondary to structural changes in the myocardium or as a result of HCM cardiomyocyte electrophysiology. In this study, we used an induced pluripotent stem cell model of the R403Q variant in myosin heavy chain 7 (MYH7) to study the electrophysiology of HCM cardiomyocytes in electrically coupled syncytia, revealing significant conduction slowing and increased spatial dispersion of repolarisation - both well-established substrates for arrhythmia.
View Article and Find Full Text PDFSci Adv
May 2024
Centre de Biologie Structurale, Université de Montpellier, CNRS, INSERM. Montpellier, France.
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