Attenuated store-operated Ca2+ entry in mesenteric artery endothelial cells of aged rat

Abstract

Objective To observe attenuated store-operated Ca2+ entry in superior mesenteric artery endothelial cells of aged rat. Methods The pressure myograph was applied to measure the vasodilation of superior mesenteric artery induced by bradykinin (BK) in aged versus non-elder rats. Primarily cultured MAECs were treated by thapsigargin (TG) and BK to deplete intracellular Ca2+ stores for comparing SOCE. SOCE of MAECs was detected by calcium imaging technology and was compared between aged and non-elder rats. The expression levels of Orai 1 and stromal interaction factor 1 (STIM 1) were observed by immunofluorescence method. Results Compared with the non-elder rats (70.0±4.1%), BK-induced vasodilation in aged rats (27.0±4.9)% was declined by (60.7±4.3)%. SOCE induced by BK and TG in primarily cultured MAECs was attenuated by 37.6% and 39.2% in aged rats (1.71±0.18 and 1.06±0.03) respectively as compared with non-elder rats (2.72±0.39 and 1.75±0.06). The expressions of SOCE's components Orai 1 and STIM 1 in MAECs were decreased obviously in aged rats than in non-elder rats. Conclusions SOCE of MAECs and SOCE-induced vasodilation are significantly attenuated in aged rats. The decreased expression level of Orai 1 and STIM 1 may contribute to this alteration. Key words: Mesenteric artery superior; Endothelial cells; Calcium