Linoleic Acid Stimulates Ca2 i Increase in Rat Pancreatic Beta-Cells through Both Membrane Receptor- and Intracellular Metabolite-Mediated PathwaysReportar como inadecuado




Linoleic Acid Stimulates Ca2 i Increase in Rat Pancreatic Beta-Cells through Both Membrane Receptor- and Intracellular Metabolite-Mediated Pathways - Descarga este documento en PDF. Documentación en PDF para descargar gratis. Disponible también para leer online.

The role of the free fatty acid FFA receptor and the intracellular metabolites of linoleic acid LA in LA-stimulated increase in cytosolic free calcium concentration Ca2+i was investigated. Ca2+i was measured using Fura-2 as indicator in rat pancreatic β-cells in primary culture. LA 20 µM for 2 min stimulated a transient peak increase followed by a minor plateau increase in Ca2+i. Elongation of LA stimulation up to 10 min induced a strong and long-lasting elevation in Ca2+i. Activation of FFA receptors by the non-metabolic agonist GW9508 40 µM for 10 min resulted in an increase in Ca2+i similar to that of 2-min LA treatment. Inhibition of acyl-CoA synthetases by Triacsin C suppressed the strong and long-lasting increase in Ca2+i. The increase in Ca2+i induced by 2 min LA or GW9508 were fully eliminated by exhaustion of endoplasmic reticulum ER Ca2+ stores or by inhibition of phospholipase C PLC. Removal of extracellular Ca2+ did not influence the transient peak increase in Ca2+i stimulated by 2 min LA or GW9508. The strong and long-lasting increase in Ca2+i induced by 10 min LA was only partially suppressed by extracellular Ca2+ removal or thapsigargin pretreatment, whereas remaining elevation in Ca2+i was eliminated after exhaustion of mitochondrial Ca2+ using triphenyltin. In conclusion, LA stimulates Ca2+ release from ER through activation of the FFA receptor coupled to PLC and mobilizes mitochondrial Ca2+ by intracellular metabolites in β-cells.



Autor: Yufeng Zhao , Li Wang , Jianhua Qiu, Dingjun Zha, Qiang Sun, Chen Chen

Fuente: http://plos.srce.hr/



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