Referenced in: none

Automatically associated channels: Cav1.1 , Kir2.1 , Kv1.1 , Slo1

Title: Electrophysiology of human cardiac atrial and ventricular telocytes.

Authors: Jingwei Sheng, Winston Shim, Jun Lu, Sze Yun Lim, Boon Hean Ong, Tien Siang Lim, Reginald Liew, Yeow Leng Chua, Philip Wong

Journal, date & volume: J. Cell. Mol. Med., 2014 Feb , 18, 355-62

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/24467431

Abstract
Telocytes (TCs) with exceptionally long cellular processes of telopodes have been described in human epicardium to act as structural supporting cells in the heart. We examined myocardial chamber-specific TCs identified in atrial and ventricular fibroblast culture using immunocytochemistry and studied their electrophysiological property by whole-cell patch clamp. Atrial and ventricular TCs with extended telopodes and alternating podoms and podomers that expressed CD34, c-Kit and PDGFR-β were identified. These cells expressed large conductance Ca²⁺-activated K⁺ current (BK(Ca)) and inwardly rectifying K⁺ current (IK(ir)), but not transient outward K⁺ current (I(to)) and ATP-sensitive potassium current (K(ATP)). The active channels were functionally competent with demonstrated modulatory response to H2 S and transforming growth factor (TGF)-β1 whereby H₂S significantly inhibited the stimulatory effect of TGF-β1 on current density of both BKCa and IK(ir). Furthermore, H₂S attenuated TGF-β1-stimulated KCa1.1/Kv1.1 (encode BK(Ca)) and Kir2.1 (encode IK(ir)) expression in TCs. Our results show that functionally competent K⁺ channels are present in human atrial and ventricular TCs and their modulation may have significant implications in myocardial physiopathology.