蛋白磷酸酶抑制剂对人成神经细胞瘤细胞钙瞬态的影响

Effects of Protein Phosphatase Inhibitor on Calcium Transient in Neuroblastoma Cells

应用荧光倒置显微镜系统，分别检测了蛋白磷酸酶ＰＰ－２Ａ和ＰＰ－１抑制剂岗田酸（Ｏｋａｄａｉｃａｃｉｄ，ＯＡ）和ＰＰ－２Ｂ抑制剂三氟吡拉嗪（Ｔｒｉｆｌｕｏｐｅｒａｚｉｎｅ，Ｔｒｉ）处理的人成神经细胞瘤细胞（ＳＨ－ＳＹ５Ｙ）胞浆钙瞬态变化。结果发现：１ｎｍｏｌ／ＬＯＡ抑制ＰＰ－２Ａ时，胞浆游离Ｃａ２＋浓度（［Ｃａ２＋］ｉ）瞬时波动明显增强，［Ｃａ２＋］ｉ在２０ｍｉｎ内逐步轻微升高，后逐渐回复；而用１００ｎｍｏｌ／ＬＯＡ同时抑制ＰＰ－２Ａ和ＰＰ－１时，则引起［Ｃａ２＋］ｉ即刻持续升高，并同时伴有［Ｃａ２＋］ｉ瞬时波动明显增强；用１００μｍｏｌ／ＬＴｒｉ抑制ＰＰ－２Ｂ时，则引起［Ｃａ２＋］ｉ即刻持续升高，［Ｃａ２＋］ｉ瞬时波动没有明显变化。提示：蛋白磷酸酶降低可能通过钙瞬态变化而参与Ａｌｚｈｅｉｍｅｒ病（ＡＤ）的发病过程。

The effects of protein phosphatase PP2A and PP1 inhibitor-okadaic acid (OA) and PP2B(calcineurin) inhibitor-trifluoperazine (Tri) on calcium transient in neuroblastoma cells (SHSY5Y) were investigated under the fluorescence inverted microscopy. The results indicated that the i was slightly increased in 20 min and then gradually returned to baseline level by incubating with 1 nmol/L OA which inhibited only PP2A. However, a rapid and steady increase of i was observed both when PP2A and PP1 were inhibited by 100 nmol/L OA or when PP2B by 100 mol/L Tri. Moreover, OA both with 1 nmol/L and 100 nmol/L could enhance instantaneous calcium fluctuation. The data suggested that an impaired protein phosphatase system might paticipate in AD pathogenesis by an alternative calcium transient pathway.