Agonist-induced Calcium Oscillations in Depolarized Fibroblasts and Their Manipulation by Photoreleased Ins(l,4,5)P3, and Ca++, and Ca++ Buffer

With the advent of techniques for measuring or even imaging cytosolic free calcium (Ca++i) in single cells (Tsien and Poenie 1986), it has become apparent that this important second messenger often shows marked oscillations. Such remarkable phenomena have been observed in a wide variety of activated cell types (Berridge et al. 1988), including early embryos (Cuthbertson et al. 1981; Cuthbertson and Cobbold 1985; Miyazaki et al. 1986), hepatocytes (Woods et al. 1986,) 1987a,b), cardiac (Orchard et al. 1983; Wier et al. 1987) and smooth (Ambler et al. 1988) muscle cells, nuerons (Gorman et al. 1982; Lipscombe et al. 198), fibroblasts (Ueda et al. 1986), lymphocytes (Wilson et al. 1987), mast cells (Neher and Almers 1986), endothelial cells (Jacob et al. 1988), and epithelial cell lines (Yada et al. 1986). Nonrepetitive or spatially uniform Ca++i is also often observed, sometimes even in cells immediately adjacent to those with more flamboyant behaviors....