Tepel M, Bachmann J, Schluter H, Zidek W
Medizinische Universitats-Poliklinik, University of Munster, Germany.
J Hypertens. 1995 Dec;13(12 Pt 2):1686-8.
To evaluate the effects of two new endogenous vasoconstricting substances, diadenosine pentaphosphate (AP5A) and diadenosine hexaphosphate (AP6A) on the cytosolic free calcium concentration in vascular smooth muscle cells.
Spectrofluorophotometric measurements of cytosolic Ca2+ were conducted in monolayers of cultured rat vascular smooth muscle cells using the calcium-sensitive fluorescent dye fura-2.
The resting Ca2+ concentration in vascular smooth muscle cells was 80 +/- 5 nmol/l (mean +/- SEM; n = 39). The addition of 10 mu mol/l AP5A or AP6A significantly increased Ca2+ in vascular smooth muscle cells to 248 +/- 55 and 358 +/- 124 nmol/l, respectively. The sustained increase in Ca2+ after administration of AP5A or AP6A was 143 +/- 40 and 148 +/- 57 nmol/l, respectively. Diadenosine polyphosphates induce a transplasmamembrane calcium influx as detected by experiments in the absence of external calcium or by using the manganese quenching technique to report unidirectional calcium fluxes. The effects of diadenosine polyphosphates were compared to those of the well known vasoconstrictor angiotensin II, which increased Ca2+ in vascular smooth muscle cells by 1053 +/- 174 nmol/l.
Diadenosine polyphosphates increase Ca2+ in vascular smooth muscle cells, thereby regulating the contractility of vascular smooth muscle and subsequently blood pressure.
评估两种新的内源性血管收缩物质，二腺苷五磷酸（AP5A）和二腺苷六磷酸（AP6A）对血管平滑肌细胞胞质游离钙浓度的影响。
使用钙敏荧光染料fura-2，对培养的大鼠血管平滑肌细胞单层进行胞质Ca2+的分光荧光光度测量。
血管平滑肌细胞的静息Ca2+浓度为80±5 nmol/L（平均值±标准误；n = 39）。添加10 μmol/L的AP5A或AP6A可使血管平滑肌细胞中的Ca2+分别显著增加至248±55和358±124 nmol/L。给予AP5A或AP6A后Ca2+的持续增加分别为143±40和148±57 nmol/L。通过在无细胞外钙的情况下进行实验或使用锰淬灭技术来报告单向钙通量，检测到二腺苷多磷酸诱导跨质膜钙内流。将二腺苷多磷酸的作用与众所周知的血管收缩剂血管紧张素II的作用进行比较，血管紧张素II可使血管平滑肌细胞中的Ca2+增加1053±174 nmol/L。
二腺苷多磷酸可增加血管平滑肌细胞中的Ca2+，从而调节血管平滑肌的收缩力以及随后的血压。
