Details

Autor(en) / Beteiligte

• Sha, Qun
• Robinson, Shawn W.
• McCulle, Stacey L.
• Shorofsky, Stephen R.
• Welling, Paul A.
• Goldman, L.
• Balke, C. William

Titel

An Antisense Oligonucleotide Against H1 Inhibits the Classical Sodium Current but not ICa(TTX) in Rat Ventricular Cells

Ist Teil von

• The Journal of physiology, 2003-03, Vol.547 (2), p.435-440

Ort / Verlag

Oxford, UK: The Physiological Society

Erscheinungsjahr

2003

Link zum Volltext

Quelle

Wiley Online Library - AutoHoldings Journals

Beschreibungen/Notizen

• I Ca(TTX) is a sodium current component, functionally distinct from the main body of sodium current, seen in cardiac and other cells. To determine if I Ca(TTX) channels are a separate isoform from the classical cardiac sodium channels, we exposed rat ventricular cells in primary culture to an antisense oligonucleotide (AON) directed against rH1 (rNa v 1.5): 5′-CTCCTCATACCCTCT-3′. The homologous human sequence has been identified (and confirmed by us on HEK 293 cells) as effective against hH1 expressed heterologously. Scrambled sequence (5′-CCCCCCTTATCTACT-3′) controls were also included. The AON (10 μ m ; day 2 of exposure) reduced the classical sodium current by 69.6 % compared to untreated and 60.8 % compared to scrambled sequence (10 μ m ; day 2 of exposure) controls (mean ± s.e.m. maximum peak inward current density of −8.23 ± 0.60 pA pF −1 , 18 cells, for untreated; −6.37 ± 0.79 pA pF −1 , 16 cells, for scrambled sequence; and −2.50 ± 0.31 pA pF −1 , 18 cells, for AON-treated cells). The two control groups are not significantly different from each other, but are both significantly different from the AON-treated group ( P < 0.001). The inhibition was specific for sodium channels, with no significant AON effect on the L-type calcium current. This confirms that H1 generates the classical cardiac sodium current. This same AON at the same concentration and time of exposure had no significant effect on I Ca(TTX) (mean of −4.72 ± 0.55, 15 cells; −5.47 ± 0.53, 13 cells; and −5.04 ± 0.63 pA pF −1 , 15 cells, for untreated controls, scrambled controls and AON treated, respectively). Hence, I Ca(TTX) , which is functionally distinct from the classical cardiac sodium current, is encoded by a distinct gene.