Electrostimulation enhances FAT/CD36-mediated long-chain fatty acid uptake by isolated rat cardiac myocytes.
We investigated palmitate uptake and utilization by contracting cardiac myocytes in suspension to explore the link between long-chain fatty acid (FA) uptake and cellular metabolism, in particular the role of fatty acid translocase (FAT)/CD36-mediated transsarcolemmal FA transport. For this, an experimental setup was developed to electrically stimulate cardiomyocytes in multiple parallel incubations. Electrostimulation at voltages > or =170 V resulted in cellular contraction with no detrimental effect on cellular integrity. At 200 V and 4 Hz, palmitate uptake (measured after 3-min incubation) was enhanced 1.5-fold. In both quiescent and contracting myocytes, after their uptake, palmitate was largely and rapidly esterified, mainly into triacylglycerols. Palmitate oxidation (measured after 30 min) contributed to 22% of palmitate taken up by quiescent cardiomyocytes and, after stimulation at 4 Hz, was increased 2.8-fold to contribute to 39% of palmitate utilization. The electrostimulation-mediated increase in palmitate uptake was blocked in the presence of either verapamil, a contraction inhibitor, or sulfo-N-succinimidyl-FA esters, specific inhibitors of FAT/CD36. These data indicate that, in contracting cardiac myocytes, palmitate uptake is increased due to increased flux through FAT/CD36.
Luiken
J J
JJ
Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, NL-6200 MD Maastricht, The Netherlands.
Willems
J
J
van der Vusse
G J
GJ
Glatz
J F
JF
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D018955:CD36 Antigens / Q000502:physiology*; D002245:Carbon Dioxide / Q000032:analysis; D002478:Cells, Cultured; D004558:Electric Stimulation; D005230:Fatty Acids, Nonesterified / Q000378:metabolism*; D006321:Heart / Q000502:physiology*; D007700:Kinetics; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism*; D027361:Organic Anion Transporters; D010084:Oxidation-Reduction; D010168:Palmitates / Q000494:pharmacology; D019308:Palmitic Acid / Q000378:metabolism; D010693:Phloretin / Q000494:pharmacology; D010743:Phospholipids / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew; D012508:Sarcolemma / Q000378:metabolism; D013388:Succinimides / Q000494:pharmacology; D014280:Triglycerides / Q000378:metabolism; D014700:Verapamil / Q000494:pharmacology
D018955:CD36 Antigens; D005230:Fatty Acids, Nonesterified; D008562:Membrane Glycoproteins; D027361:Organic Anion Transporters; D010168:Palmitates; D010743:Phospholipids; D013388:Succinimides; D014280:Triglycerides; C097197:sulfo-N-succinimidyl palmitate; D002245:Carbon Dioxide; D019308:Palmitic Acid; D014700:Verapamil; D010693:Phloretin