Bielkiewicz-Vollrath B, Carpenter J R, Schulz R, Cook D A
Mol Pharmacol. 1987 May;31(5):513-22.
We have examined the time course of the formation of inositol mono-, bis-, tris, and tetrakisphosphates (InsP1, InsP2, InsP3, and InsP4, respectively) in slices of the longitudinal muscle of guinea pig small intestine that had been prelabeled with myo-3H-inositol. The agonists employed were histamine and carbachol. InsP3 increases immediately with a time course which is similar to that of the increase in contractile force and remains elevated for the rest of the incubation period. High performance liquid chromatography analysis revealed that InsP3 is composed of two isomers, the 1,4,5- and 1,3,4-isomers. The release of 1,4,5-inositol trisphosphate [Ins(1,4,5)P3] was followed by the rapid accumulation of InsP4 and later on by the formation of 1,3,4-inositol trisphosphate [Ins(1,3,4)P3]. Ins(1,3,4)P3 and InsP4 were identified by co-chromatography with the Ins(1,3,4)P3 and 1,3,4,5-inositol tetrakisphosphate prepared from 3H-Ins(1,4,5)P3 using a kinase from rat brain. The time course of accumulation of these compounds is consistent with a second messenger role of Ins(1,4,5)P3 in initiation of smooth muscle contraction.
我们检测了预先用3H-肌醇标记的豚鼠小肠纵肌切片中肌醇单磷酸、双磷酸、三磷酸和四磷酸（分别为InsP1、InsP2、InsP3和InsP4）形成的时间进程。所用的激动剂是组胺和卡巴胆碱。InsP3立即增加，其时间进程与收缩力增加的时间进程相似，并在其余孵育期内保持升高。高效液相色谱分析显示InsP3由两种异构体组成，即1,4,5-异构体和1,3,4-异构体。1,4,5-肌醇三磷酸[Ins(1,4,5)P3]释放后，InsP4迅速积累，随后形成1,3,4-肌醇三磷酸[Ins(1,3,4)P3]。通过与用大鼠脑激酶从3H-Ins(1,4,5)P3制备的Ins(1,3,4)P3和1,3,4,5-肌醇四磷酸共色谱法鉴定了Ins(1,3,4)P3和InsP4。这些化合物积累的时间进程与Ins(1,4,5)P3在平滑肌收缩起始中的第二信使作用一致。
