Dietary (n-3) polyunsaturated fatty acids exert antihypertensive effects by modulating calcium signaling in T cells of rats.
After 10 wk of feeding an experimental diet enriched with (n-3) polyunsaturated fatty acids (PUFA), i.e., eicosapentaenoic acid [EPA, 20:5(n-3)] and [DHA, 22:6(n-3)] (EPAX), blood pressure in spontaneously hypertensive rats (SHR), but not in normotensive Wistar-Kyoto (WKY) rats was reduced relative to rats fed an unsupplemented control diet. Concanavalin A-stimulated T-cell proliferation was diminished in both strains of rats fed the PUFA/EPAX diet. The experimental diet lowered secretion of interleukin-2 in SHR, but not in WKY rats compared with rats fed the control diet. To determine whether there was a defect in calcium homeostasis in T cells during hypertension, we employed the following agents: caffeine, which recruits calcium from the cytosolic Ca(2+)-induced Ca(2+)-release pool; ionomycin, which at low concentrations opens calcium channels; and thapsigargin (TG), which mobilizes [Ca(2+)]i from the endoplasmic reticulum (ER) pool. Caffeine-induced increases in [Ca(2+)]i were not modified by the PUFA/EPAX diet. The ionomycin-induced increases in [Ca(2+)]i in T cells from SHR were greater than in those from WKY rats; consumption of the PUFA/EPAX diet did not modify Ca(2+) influx in cells of either strain. The TG-induced increases in [Ca(2+)]i in T cells from SHR were greater than those in cells from WKY rats. Interestingly, consumption of the experimental diet reduced TG-evoked increases in [Ca(2+)]i in T cells from SHR and increased those in T cells from WKY rats, indicating that the PUFA/EPAX diet could reverse the calcium mobilization from the ER pool in T cells. These results suggest that (n-3) PUFA exert antihypertensive effects and modulate T-cell calcium signaling during hypertension in rats.
Triboulot
C
C
UPRES Lipids & Nutrition, Faculty of Life Sciences, Université de Bourgogne, Dijon 21000, France.
Hichami
A
A
Denys
A
A
Khan
N A
NA
D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001667:Binding, Competitive; D020013:Calcium Signaling / Q000187:drug effects*; D004041:Dietary Fats / Q000494:pharmacology*; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated / Q000378:metabolism / Q000494:pharmacology*; D007165:Immunosuppression Therapy; D007425:Intracellular Membranes / Q000378:metabolism; D008297:Male; D010743:Phospholipids / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D013601:T-Lymphocytes / Q000378:metabolism*
D000959:Antihypertensive Agents; D004041:Dietary Fats; D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D010743:Phospholipids