Fetal calf serum, RPMI-1640 culture medium and antibiotics were from Biological Industries (Bet-Haemek, Israel). Fura-2 AM was from either Molecular Probes (Eugene, OR, USA) or from Teflabs (Austin, TX, USA). The dye was stored in solid form at -20°C and fresh solutions were made before each experiment in dry dimethyl sulphoxide (DMSO). Phorbol 12-myristate, 13-acetate (TPA), 8,8′-[carbonylbis [imino-3,1-phenylenecarbonylimino (4-methyl-3,1-phenylene) carbonylimino]] bis-1, 3, 5-naphthalenetrisulphonic acid hexasodium (Suramin hexasodium) and RP-adenosine 3′, 5′-cyclic monophosphothioate triethylamine (Rp-cAMPS) were from RBI (Natick, MA, USA). 1-(6-((17β-3-Methoxyestra-1, 3, 5 (10)-trien-17-yl) amino) hexyl)-1H-pyrrole-2, 5-dione (U-73122), 6-anilino-5, 8-quinolinedione (LY-83583), bisindolylmaleimide I (GF 109203X) and KT-5823 were from Calbiochem (La Jolla, CA, USA). L-NAME was from Biomol (Plymouth Meeting, PA, USA). All other materials were obtained from Sigma (USA). The standard Ringer solution was composed of (mM): 150 NaCl, 2.5 KCl, 1.5 CaCl2, 1.5 MgCl2, 5 D-glucose and 5 Hepes. The pH of all the solutions was set to 7.4 with NaOH and HCl.
TPA, GF 109203X, U-73122 and KT-5823 were dissolved in DMSO, chelerythrine chloride was dissolved in DMSO/H2O (1:1), and LY-83583 was dissolved in CH3OH/C2H5OH (1:1). Stock solutions of ATP and UTP were prepared in 0.05 M Hepes buffer (pH 7.4) and diluted into the Ringer solutions just prior to use. All other chemicals were dissolved in water. The final concentration of DMSO was not more than 0.1 %, and that of the alcohol not more than 0.5 %.