U-73122 (U73122) , an effective PLC inhibitor, reduces agonist-induced Ca2+ increases in platelets and PMN.

0.1 mg/ml U73122分别抑制狗体内角叉菜胶诱导的74%淋巴细胞和65%巨噬细胞积累到皮下腔隙.30 mg/kg U73122（i.p.）阻断角叉菜胶处理1小时和3小时后大鼠后爪65%和80%的水肿.其还完全抑制小鼠腹膜炎模型中脂多糖诱导的巨噬细胞和淋巴细胞浸润,以及前列腺素E2(80%),并且也会抑制12-O-十四酰-佛波醇-13-乙酸盐诱导的小鼠耳肿胀.

U-73122抑制胶原蛋白诱导的血栓素B的产生,胶原蛋白通过抑制受体耦合的花生四烯酸转移产生诱导作用。U73122也会抑制FMLP诱导的人多形核中性白细胞聚合,以及相关的IP3和甘油二酯的产生。U73122明显抑制各种激动剂,包括凝血酶,胶原蛋白,ADP,花生四烯酸诱导的人血小板的聚集（IC50为1-5 μM）。凝血酶或者U-46619通过抑制被血小板可溶组分催化的磷脂酰[3H]肌糖和磷脂酰[3H]肌糖4,5-二磷酸的水解（Ki：9/40 μM）,诱导IP3的产生和随后细胞溶质中Ca2+的快速增加,10 μM U-73122会对其产生抑制。

PMNs (4×107/4 mL) are incubated with U-73122 according to protocols. The reactions are stopped with cold calcium-free PBS. The cells are centrifuged at 750 × g (4°C) and resuspended in 1 mL of Triton X-100-free extraction buffer (50 mM Tris, pH 7.5, 50 mM fimercaptoethanol, 2 mM EGTA, 1 mM phenylmethylsulfonyl fluoride and 4 μg/mL of leupeptin, soybean trypsin inhibitor and aprotinin), and then sonicated for 10- and 5-sec consecutive bursts at 20% output. The lysates are centrifuged at 240 × g (4°C) for 20 mm in a TL-100 ultracentrifuge with the supernatant designated as the cytosol fraction. The pellet is resuspended in 1% Triton-containing extraction buffer, sonicated, shaken for 30 mm at 4°C and centrifuged (240 × g for 20 mm at 4°C). The supernatant constitutes the extractable particulate fraction, and the pellet is sonicated in extraction buffer with Triton and constituted the nonextractable particulate fraction.

U-73122 is dissolved in DMSO. Agonist-induced production of IP3 in PMN is measured by use of the competitive radiobinding assy. PMN (2 x 106-107) in 0.2 mL of phosphate-buffered saline, pH 7.4 [NaC1 (138 mM), Na2HPO4 (8.1 mM), KH2PO4 (1.5 mM), KCI (2.7 mM), CaCl2 (1.0 mM), MgC12 (1.0 mM) and glucose (0.1%, w/v)] are incubated in conical polypropylene tubes at 37°C in a shaking water bath. U-73122 or U-73343 is added (in 1 μL of DMSO) 3 min before the addition of agonist, FMLP (0.1 μM) plus cytochalasin B (5 μg/mL). FMLP and cytochalasin B are added in 1 μL each of DMSO and ethanol, respectively. Appropriate vehicle controls are included in each experiment. PMN incubation mixtures are quenched with the addition of 0.07 mL of ice-cold TCA (20%, w/v) and a portion (0.2 mL) of the TCA extract is processed for the measurement of IP3 by competitive radiobinding as described above for platelets.