Incorporated sarcolemmal fish oil fatty acids shorten pig ventricular action potentials.

Abstract

BACKGROUND:

Omega-3 polyunsaturated fatty acids (omega3-PUFAs) from fish oil reduce the risk of sudden death presumably by preventing life-threatening arrhythmias. Acutely administered omega3-PUFAs modulate the activity of several cardiac ion channels, but the chronic effects of a diet enriched with fish oil leading to omega3-PUFA-incorporation into the sarcolemma on membrane currents are unknown.

METHODS:

Pigs received a diet either rich in omega3-PUFAs or in omega9-fatty acids for 8 weeks. Ventricular myocytes (VMs) were isolated and used for patch-clamp studies.

RESULTS:

omega3-VMs contained higher amounts of omega3-PUFAs and had a shorter action potential (AP) with a more negative plateau than control VM. In omega3 VMs, L-type Ca(2+) current (I(Ca,L)) and Na(+)-Ca(2+) exchange current (I(NCX)) were reduced by approximately 20% and 60%, respectively, and inward rectifier K(+) current (I(K1)) and slow delayed rectifier K(+) current (I(Ks)) were increased by approximately 50% and 70%, respectively, compared to control. Densities of rapid delayed rectifier K(+) current, Ca(2+)-activated Cl(-) current, and Na(+) current (I(Na)) were unchanged, although voltage-dependence of I(Na) inactivation was more negative in omega3 VMs.

CONCLUSIONS:

A fish oil diet increases omega3-PUFA content in the ventricular sarcolemma, decreases I(Ca,L) and I(NCX), and increases I(K1) and I(Ks), resulting in AP shortening. Incorporation of omega3-PUFAs in the sarcolemma may have consequences for arrhythmias independent of circulating omega3-PUFAs.

• Authors: Arie O Verkerk, Antoni C G van Ginneken, Géza Berecki, Hester M den Ruijter, Cees A Schumacher, Marieke W Veldkamp, Antonius Baartscheer, Simona Casini, Tobias Opthof, Robert Hovenier, Jan W T Fiolet, Peter L Zock, Ruben Coronel
• Journal: Cardiovascular research (Cardiovasc Res) Vol. 70 Issue 3 Pg. 509-20 (Jun 01 2006) ISSN: 0008-6363 [Print] England
• PMID: 16564514 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Antioxidants
• Calcium Channel Blockers
• Calcium Channels
• Chromans
• Fatty Acids, Omega-3
• Fish Oils
• Sodium Channels
• Sodium-Calcium Exchanger
• 2,2,5,7,8-pentamethyl-1-hydroxychroman
• Nifedipine
• 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid

Topics

• 4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid
• Action Potentials (physiology)
• Animals
• Antioxidants (pharmacology)
• Arrhythmias, Cardiac (metabolism)
• Calcium Channel Blockers (pharmacology)
• Calcium Channels (metabolism)
• Chromans (pharmacology)
• Diet
• Fatty Acids, Omega-3 (administration & dosage)
• Fish Oils
• Heart Ventricles
• Male
• Membrane Potentials (physiology)
• Myocytes, Cardiac (metabolism, physiology)
• Nifedipine (pharmacology)
• Patch-Clamp Techniques
• Sarcolemma (metabolism, physiology)
• Sodium Channels (metabolism)
• Sodium-Calcium Exchanger (physiology)
• Swine
• Time Factors