|  Help  |  About  |  Contact Us

Publication : Expression pattern of neuronal and skeletal muscle voltage-gated Na+ channels in the developing mouse heart.

First Author  Haufe V Year  2005
Journal  J Physiol Volume  564
Issue  Pt 3 Pages  683-96
PubMed ID  15746173 Mgi Jnum  J:109097
Mgi Id  MGI:3625769 Doi  10.1113/jphysiol.2004.079681
Citation  Haufe V, et al. (2005) Expression pattern of neuronal and skeletal muscle voltage-gated Na+ channels in the developing mouse heart. J Physiol 564(Pt 3):683-96
abstractText  In the mammalian heart, a variety of voltage-gated Na(+) channel transcripts and proteins have been detected. However, little quantitative information is available on the abundance of each transcript during development, or the contribution of TTX-sensitive Na(+) channels to the cardiac sodium current (I(Na)). Using competitive and real-time RT-PCR we investigated the transcription of six Na(+) channels (Na(v)1.1-Na(v)1.6) and the beta1 subunit during mouse heart development. Na(v)1.5 was predominantly expressed in the adult heart, whereas the splice variant Na(v)1.5a was the major Na(+) channel isoform in embryonic hearts. The TTX-resistant Na(+) channel transcripts (Na(v)1.5 and Na(v)1.5a) increased 1.7-fold during postnatal development. Transcripts encoding TTX-sensitive Na(+) channels (Na(v)1.1-Na(v)1.4) and the beta1 subunit gradually increased up to fourfold from postnatal day (P)1 to P126, while the Na(v)1.6 transcript level remained low and constant over the same period. In adults, TTX-sensitive channel mRNA accounted for 30-40% of the channel pool in whole-heart preparations (Na(v)1.3 > Na(v)1.4 > Na(v)1.2 >> Na(v)1.1 approximately Na(v)1.6), and 16% in mRNA from isolated cardiomyocytes (Na(v)1.4 > Na(v)1.3 > Na(v)1.2 > Na(v)1.1 > Na(v)1.6). Confocal immunofluorescence on ventricular myocytes suggested that Na(v)1.1 and Na(v)1.2 were localized at the intercalated disks and in the t tubules. Na(v)1.3 labelling predominantly produced a diffuse but strong intracellular signal. Na(v)1.6 fluorescence was detected only along the Z lines. Electrophysiological recordings showed that TTX-sensitive and TTX-resistant Na(+) channels, respectively, accounted for 8% and 92% of the I(Na) in adult ventricular cardiomyocytes. Our data suggest that neuronal and skeletal muscle Na(+) channels contribute to the action potential of cardiomyocytes in the adult mammalian heart.
Quick Links:
 
Quick Links:
 

Expression

Publication --> Expression annotations

 

Other

13 Bio Entities

Trail: Publication

111 Expression

Trail: Publication