Oleic acid versus linoleic and α-linolenic acid. different effects on Ca2+ signaling in rat thymocytes.

Oleic acid is the principal fatty acid of olive oil composition and is reported to play a crucial role in its healthy aspects. However, the detailed mechanism of action is poorly understood. This study aims to elucidate the role of oleic acid in calcium signaling in rat thymocytes, in comparison to linoleic and linolenic acid. Fatty acids were applied to thymocytes isolated from wistar rats and loaded with Fura-2 to measure calcium signals. The main results showed a concentration-dependent increase in [Ca(2+)](i) induced by the 3 fatty acids. Raising the number of unsaturations resulted in greater increases. Two different pathways contributed to the increase induced by the polyunsaturated fatty acids: an IP(3)- independent release from the thapsigargin-sensitive stores and an extracellular calcium entry by econazole and nifedipine-insensitive channels. However, the OA-induced increases in [Ca(2+)](i) seemed to be due mostly to the Ca(2+) recruited from the intracellular stores. This study demonstrates that the fatty acids tested induce increases in [Ca(2+)](i) in rat thymocytes, with differences in close relation to the degree of unsaturation. Such differences could be responsible for their different physiological action.