Angiotensin II induced biphasic inositol 1,4,5-triphosphate response in rat vascular smooth muscle cells

We examined angiotensin II induced changes of inositol 1,4,5-triphosphate (Ins(1,4,5)P3) in cultured vascular smooth muscle cells from spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY) using a specific protein binding assay system. We observed a rapid biphasic Ins(1,4,5)P3 response, which peaked at 5 s and at 30 s after angiotensin II stimulation. At every period of time the Ins(1,4,5)P3 level of SHR was 2- to 5-fold higher than that of WKY. Thus, the Ins(1,4,5)P3 specific assay revealed a complex Ins(1,4,5)P3 response after angiotensin II stimulation and suggested the need for further investigation of the Ins(1,4,5)P3 metabolism following agonist stimulation in vascular smooth muscle cells.