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Quantitative analysis of voltage-gated potassium currents from primary equine (Equus caballus) and elephant (Loxodonta africana) articular chondrocytes.
Abstract: In this comparative study, we have established in vitro models of equine and elephant articular chondrocytes, examined their basic morphology, and characterized the biophysical properties of their primary voltage-gated potassium channel (Kv) currents. Using whole cell patch-clamp electrophysiological recording from first-expansion and first-passage cells, we measured a maximum Kv conductance of 0.15 +/- 0.04 pS/pF (n = 10) in equine chondrocytes, whereas that in elephant chondrocytes was significantly larger (0.8 +/- 0.4 pS/pF, n = 4, P </= 0.05). Steady-state activation parameters of elephant chondrocytes (V = -22 +/- 6 mV, k = 11.8 +/- 3 mV, n = 4) were not significantly different from those of horse chondrocytes (V = -12.5 +/- 4.3 mV, k = 12 +/- 2, n = 10). This suggests that there would be slightly more resting Kv activation in elephant chondrocytes than in their equine counterparts. Kinetic analysis revealed that both horse and elephant chondrocyte Kv currents had similar activation and inactivation parameters. Pharmacological investigation of equine chondrocyte Kv currents showed them to be powerfully inhibited by the potassium channel blockers tetraethylammonium and 4-aminopyridine but not by dendrotoxin-I. Immunohistochemical studies using polyclonal antibodies to Kv1.1-Kv1.5 provided evidence for expression of Kv1.4 in equine chondrocytes. This is the first electrophysiological study of equine or elephant chondrocytes. The data support the notion that voltage-gated potassium channels play an important role in regulating the membrane potential of articular chondrocytes and will prove useful in future modeling of electromechanotransduction of fully differentiated articular chondrocytes in these and other species.
Publication Date: 2005-03-31 PubMed ID: 15802557DOI: 10.1152/ajpregu.00710.2004Google Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
Summary
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This study developed in vitro models of horse and elephant cartilage cells (chondrocytes), examined their basic structure, and analysed the biophysical properties of their main voltage-gated potassium channel currents. These studies are crucial to understanding cell membrane potential regulation and could aid in modelling the process of electromechanotransduction in these cells.
Research Purpose and Methodology
- The aim of this study was to create in vitro models of articular chondrocytes (cells that make up cartilage) from horses and elephants, investigate their morphology, and understand their key biophysical properties, particularly voltage-gated potassium channel currents.
- The researchers used a technique called whole-cell patch-clamp electrophysiological recording to measure these currents in first-expansion and first-passage cells.
Findings: Equine vs Elephant Chondrocytes
- The study found that the maximum conductance of these currents was 0.15 +/- 0.04 pS/pF in horse chondrocytes and significantly larger (0.8 +/- 0.4 pS/pF) in elephant chondrocytes.
- However, the steady-state activation parameters were not significantly different, suggesting slightly more resting activation in elephant chondrocytes.
- Kinetic analysis showed similar activation and inactivation parameters for the currents in both horse and elephant chondrocytes.
Pharmacological and Immunohistochemical Studies
- Pharmacological investigation revealed that the horse chondrocyte currents were significantly inhibited by potassium channel blockers tetraethylammonium and 4-aminopyridine, but not by dendrotoxin-I.
- Immunohistochemical studies, which use antibodies to detect specific proteins, provided evidence for the expression of Kv1.4 in horse chondrocytes.
Implications and Conclusions
- This is the first electrophysiological study of these chondrocytes types and it supports the idea that voltage-gated potassium channels are integral in regulating the membrane potential of these cells.
- The findings could be useful in future modelling of the process of electromechanotransduction – how mechanical forces are converted into electrical signals – in fully differentiated articular chondrocytes from these and other species.
Cite This Article
APA
Mobasheri A, Gent TC, Womack MD, Carter SD, Clegg PD, Barrett-Jolley R.
(2005).
Quantitative analysis of voltage-gated potassium currents from primary equine (Equus caballus) and elephant (Loxodonta africana) articular chondrocytes.
Am J Physiol Regul Integr Comp Physiol, 289(1), R172-R180.
https://doi.org/10.1152/ajpregu.00710.2004 Publication
Researcher Affiliations
- Faculty of Veterinary Science, University of Liverpool, Liverpool L69 7ZJ, United Kingdom.
MeSH Terms
- 4-Aminopyridine / pharmacology
- Animals
- Cartilage, Articular / cytology
- Cartilage, Articular / metabolism
- Chondrocytes / metabolism
- Elapid Venoms / pharmacology
- Electrophysiology
- Elephants / metabolism
- Horses / metabolism
- Immunohistochemistry
- Kinetics
- Models, Biological
- Potassium Channel Blockers / pharmacology
- Potassium Channels, Voltage-Gated / drug effects
- Potassium Channels, Voltage-Gated / metabolism
- Potassium Channels, Voltage-Gated / physiology
- Tetraethylammonium / pharmacology
Citations
This article has been cited 17 times.- Takács R, Kovács P, Ebeid RA, Almássy J, Fodor J, Ducza L, Barrett-Jolley R, Lewis R, Matta C. Ca(2+)-Activated K(+) Channels in Progenitor Cells of Musculoskeletal Tissues: A Narrative Review. Int J Mol Sci 2023 Apr 5;24(7).
- Abdallat R, Kruchek E, Matta C, Lewis R, Labeed FH. Dielectrophoresis as a Tool to Reveal the Potential Role of Ion Channels and Early Electrophysiological Changes in Osteoarthritis. Micromachines (Basel) 2021 Aug 11;12(8).
- Zhang K, Wang L, Liu Z, Geng B, Teng Y, Liu X, Yi Q, Yu D, Chen X, Zhao D, Xia Y. Mechanosensory and mechanotransductive processes mediated by ion channels in articular chondrocytes: Potential therapeutic targets for osteoarthritis. Channels (Austin) 2021 Dec;15(1):339-359.
- Haidar O, O'Neill N, Staunton CA, Bavan S, O'Brien F, Zouggari S, Sharif U, Mobasheri A, Kumagai K, Barrett-Jolley R. Pro-inflammatory Cytokines Drive Deregulation of Potassium Channel Expression in Primary Synovial Fibroblasts. Front Physiol 2020;11:226.
- Asmar A, Barrett-Jolley R, Werner A, Kelly R Jr, Stacey M. Membrane channel gene expression in human costal and articular chondrocytes. Organogenesis 2016 Apr 2;12(2):94-107.
- Li X, Liu C, Liang W, Ye H, Chen W, Lin R, Li Z, Liu X, Wu M. Millimeter wave promotes the synthesis of extracellular matrix and the proliferation of chondrocyte by regulating the voltage-gated K+ channel. J Bone Miner Metab 2014 Jul;32(4):367-77.
- Mobasheri A, Lewis R, Ferreira-Mendes A, Rufino A, Dart C, Barrett-Jolley R. Potassium channels in articular chondrocytes. Channels (Austin) 2012 Nov-Dec;6(6):416-25.
- Lewis R, Feetham CH, Gentles L, Penny J, Tregilgas L, Tohami W, Mobasheri A, Barrett-Jolley R. Benzamil sensitive ion channels contribute to volume regulation in canine chondrocytes. Br J Pharmacol 2013 Apr;168(7):1584-96.
- Hdud IM, El-Shafei AA, Loughna P, Barrett-Jolley R, Mobasheri A. Expression of Transient Receptor Potential Vanilloid (TRPV) channels in different passages of articular chondrocytes. Int J Mol Sci 2012;13(4):4433-4445.
- Varga Z, Juhász T, Matta C, Fodor J, Katona É, Bartok A, Oláh T, Sebe A, Csernoch L, Panyi G, Zákány R. Switch of voltage-gated K+ channel expression in the plasma membrane of chondrogenic cells affects cytosolic Ca2+-oscillations and cartilage formation. PLoS One 2011;6(11):e27957.
- Ramachandran M, Achan P, Salter DM, Bader DL, Chowdhury TT. Biomechanical signals and the C-type natriuretic peptide counteract catabolic activities induced by IL-1β in chondrocyte/agarose constructs. Arthritis Res Ther 2011;13(5):R145.
- Barrett-Jolley R, Lewis R, Fallman R, Mobasheri A. The emerging chondrocyte channelome. Front Physiol 2010;1:135.
- Lewis R, Asplin KE, Bruce G, Dart C, Mobasheri A, Barrett-Jolley R. The role of the membrane potential in chondrocyte volume regulation. J Cell Physiol 2011 Nov;226(11):2979-86.
- Mobasheri A, Lewis R, Maxwell JE, Hill C, Womack M, Barrett-Jolley R. Characterization of a stretch-activated potassium channel in chondrocytes. J Cell Physiol 2010 May;223(2):511-8.
- Ponce A, Jimenez L, Roldan ML, Shoshani L. Ion Currents Mediated by TRPA1 Channels in Freshly Dissociated Rat Articular Chondrocytes: Biophysical Properties and Regulation by Inflammatory Processes. Pharmaceuticals (Basel) 2025 Feb 26;18(3).
- Ponce A, Ogazon Del Toro A, Jimenez L, Roldan ML, Shoshani L. Osmotically Sensitive TREK Channels in Rat Articular Chondrocytes: Expression and Functional Role. Int J Mol Sci 2024 Jul 18;25(14).
- Wang X, Li X. Regulation of pain neurotransmitters and chondrocytes metabolism mediated by voltage-gated ion channels: A narrative review. Heliyon 2023 Jul;9(7):e17989.
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