Vander Kooy D, Dubyak G R, Moore R M, Moore J J
Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44109.
Endocrinology. 1989 Apr;124(4):2005-12. doi: 10.1210/endo-124-4-2005.
Human amnion is hypothesized to be a target tissue for hormone messages from the fetus regarding labor. We have previously demonstrated prostaglandin E2 (PGE2) release in amnion after treatment with phorbol and oxytocin, but other potential agonists of the inositol phospholipid/protein kinase-C system have not been investigated. The effects of extracellular ATP on cytosolic calcium concentration [( Ca2+])i) inositol phosphate (IP) accumulation, and PGE2 production were studied in cultured human amnion cells. Intracellular free calcium [Ca2+]i was measured using the fluorescent dye fura-2. Addition of 0.01-30 microM ATP resulted in a [Ca2+]i transient which peaked within 15 sec and returned to baseline over 10 min. UTP (1 microM) was more effective than ATP (1 microM); [Ca2+]i levels rose from 233 to 2880 nM (UTP) and 2320 nM (ATP). A reduced effect was observed with other nucleotides in a rank order of agonist potency of ITP greater than CTP greater than ADP greater than GTP greater than TTP. No effect was seen with AMP, cAMP, or adenosine. This is consistent with P2 purinoceptors, as described in other tissues. ATP (100 microM) also dramatically increased IP accumulation. Inositol triphosphate, inositol bisphosphate, and inositol monophosphate were increased 7-, 9-, and 16-fold respectively. The agonist potency order of other nucleotides for IP accumulation was the same as that of [Ca2+]i. Pharmacological concentrations of ATP (1 mM) were required to increase PGE2 production. Many other nucleotides were equally effective at this concentration. ATP activates the phospholipase-C system in human amnion, as demonstrated by the increase in [Ca2+]i and inositol phosphates. The physiological significance of purinergic stimulation of this tissue remains unclear.
人类羊膜被假定为来自胎儿的关于分娩的激素信息的靶组织。我们之前已经证明，在用佛波酯和催产素处理后羊膜中会释放前列腺素E2（PGE2），但尚未研究肌醇磷脂/蛋白激酶-C系统的其他潜在激动剂。研究了细胞外ATP对培养的人羊膜细胞胞质钙浓度[（Ca2+]i）、肌醇磷酸（IP）积累和PGE2产生的影响。使用荧光染料fura-2测量细胞内游离钙[Ca2+]i。添加0.01 - 30 microM的ATP会导致[Ca2+]i瞬时升高，在15秒内达到峰值，并在10分钟内恢复到基线水平。1 microM的UTP比1 microM的ATP更有效；[Ca2+]i水平从233 nM升至2880 nM（UTP）和2320 nM（ATP）。观察到其他核苷酸的作用减弱，其激动剂效力顺序为ITP大于CTP大于ADP大于GTP大于TTP。AMP、cAMP或腺苷未观察到作用。这与其他组织中描述的P2嘌呤受体一致。100 microM的ATP也显著增加IP积累。肌醇三磷酸、肌醇二磷酸和肌醇单磷酸分别增加了7倍、9倍和16倍。其他核苷酸对IP积累的激动剂效力顺序与[Ca2+]i相同。需要药理浓度的ATP（1 mM）来增加PGE2产生。在此浓度下，许多其他核苷酸同样有效。如[Ca2+]i和肌醇磷酸的增加所示，ATP激活人羊膜中的磷脂酶-C系统。这种组织的嘌呤能刺激的生理意义仍不清楚。
