Mechanically induced potentials in rat atrial fibroblasts depend on actin and tubulin polymerisation

Citation
A. Kamkin et al., Mechanically induced potentials in rat atrial fibroblasts depend on actin and tubulin polymerisation, PFLUG ARCH, 442(4), 2001, pp. 487-497
Citations number
25
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Physiology
Journal title
PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY
ISSN journal
0031-6768 → ACNP
Volume
442
Issue
4
Year of publication
2001
Pages
487 - 497
Database
ISI
SICI code
0031-6768(200107)442:4<487:MIPIRA>2.0.ZU;2-D
Abstract
When atrial tissue contracts, mechanically induced potentials (MIPs) are ge nerated in fibroblasts, presumably by activation of a non-selective cation conductance G(ns). Non-stimulated atrial fibroblasts had a mean ( SD) membr ane potential (Em) of -22 +/-2 mV and an input resistance of 510 +/- 10 M O mega. MIP amplitude (A(MIP)) was 38 +/-4 mV when current injection had pola rised E-m to Vm=-50 mV. The slope of the function relating A(MIP) to Vm can be regarded as a mechanosensitive factor (X-ms) that describes the relativ e increase in Gls during a MIR Putative involvement of cytoskeletal fibres in activation of G(ns) was studied by delivering drugs from the intracellul ar recording, microelectrode. Destabilisation of F-actin by 0.2 mM cytochal asin D reduced A(MIP) from 38 to 16 mV and X-ms from 5 to 1.8. Destabilisat ion of tubulin with 0.2 mM colchicine reduced A(MIP) to 21 mV and X-ms to 2 .1. The combination colchicine plus cytochalasin D reduced A(MIP) to 9 mV a nd X-ms to 1.4. Promoting F-actin stability with exogenous adenosine 5 ' -t riphosphate (ATP) increased A(MIP) and X-ms and attenuated the effects of c ytochalasin D. Similarly, facilitation of tubulin stability with guanosine 5 ' -triphosphate (GTP) or taxol increased A(MIP) and X-ms and attenuated t he effects of colchicine. The results suggest that transfer of mechanical e nergy from the deformed fibroblast surface to the G(ns) channel protein dep ends on intact F-actin and tubulin fibres.