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C‐type natriuretic peptide activates a non‐selective cation current in acutely isolated rat cardiac fibroblasts via natriuretic peptide C receptor‐mediated signalling
Author(s) -
Rose R. A.,
Hatano N.,
Ohya S.,
Imaizumi Y.,
Giles W. R.
Publication year - 2007
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2006.120832
Subject(s) - trpc3 , natriuretic peptide , endocrinology , medicine , trpc5 , brain natriuretic peptide , trpc , receptor , phospholipase c , transient receptor potential channel , agonist , npr2 , atrial natriuretic peptide , pertussis toxin , protein kinase c , chemistry , biology , signal transduction , g protein , microbiology and biotechnology , heart failure
In the heart, fibroblasts play an essential role in the deposition of the extracellular matrix and they also secrete a number of hormonal factors. Although natriuretic peptides, including C‐type natriuretic peptide (CNP) and brain natriuretic peptide, have antifibrotic effects on cardiac fibroblasts, the effects of CNP on fibroblast electrophysiology have not been examined. In this study, acutely isolated ventricular fibroblasts from the adult rat were used to measure the effects of CNP (2 × 10 −8 m ) under whole‐cell voltage‐clamp conditions. CNP, as well as the natriuretic peptide C receptor (NPR‐C) agonist cANF (2 × 10 −8 m ), significantly increased an outwardly rectifying non‐selective cation current (NSCC). This current has a reversal potential near 0 mV. Activation of this NSCC by cANF was abolished by pre‐treating fibroblasts with pertussis toxin, indicating the involvement of G i proteins. The cANF‐activated NSCC was inhibited by the compounds Gd 3+ , SKF 96365 and 2‐aminoethoxydiphenyl borate. Quantitative RT‐PCR analysis of mRNA from rat ventricular fibroblasts revealed the expression of several transient receptor potential (TRP) channel transcripts. Additional electrophysiological analysis showed that U73122, a phospholipase C antagonist, inhibited the cANF‐activated NSCC. Furthermore, the effects of CNP and cANF were mimicked by the diacylglycerol analogue 1‐oleoyl‐2‐acetyl‐ sn ‐glycerol (OAG), independently of protein kinase C activity. These are defining characteristics of specific TRPC channels. More detailed molecular analysis confirmed the expression of full‐length TRPC2, TRPC3 and TRPC5 transcripts. These data indicate that CNP, acting via the NPR‐C receptor, activates a NSCC that is at least partially carried by TRPC channels in cardiac fibroblasts.