... were coexpressed in PC12h cells, and their interaction was analyzed by measuring changes in fluorescence intensity Increases in cellular calcium and Ins(1,4,5)P3 were induced using carbachol (CCh; ... of these calcium increases were accompanied by increased Ins(1,4,5)P3, indicating that calcium can enhance receptor -induced Ins(1,4,5)P3 increases The peak Ins(1,4,5)P3 increases were similar ... Ins(1,4,5)P3 increases The level of receptor -induced Ins(1,4,5)P3 was about half that induced by the combination of receptor and calcium, and was further enhanced by the subsequent increase in...