Calcium Signaling Regulation in Cells

Krebs-Henseleit (KH) solution and the nominally Ca²⁺-free solution were prepared as previously described [24 (link)]. Membrane permeant acetoxymethyl (AM) ester forms of Fura-2 and Pluronic F127 were obtained from Invitrogen (Carlsbad, USA). Uridine 5′-triphosphate (UTP), uridine 5′-diphosphate (UDP), adenosine 5′-(γ-thio)triphosphate (ATPγS), forskolin, poly-l-arginine hydrochloride, SQ 22536, U73122, E₂, and G1 were obtained from Sigma-Aldrich (St. Louis, USA). G15 was obtained from Tocris (Bristol, UK). H89 dihydrochloride and MDL 12330A were obtained from Calbiochem (La Jolla, USA). All other general laboratory reagents were obtained from Sigma-Aldrich, and all cell culture reagents were obtained from Invitrogen.