cholecystokinin and mastoparan

Microfluorimetry of fura-2 was used to monitor [Ca2+]i in single cells stimulated with the G-protein activating agent mastoparan. Mastoparan induced the generation of [Ca2+]i oscillations, which in contrast to oscillations induced by low concentrations of CCK were acutely dependent on the presence of extracellular Ca2+. Oscillations were inhibited by phorbol ester. Sodium fluoride, a known activator of G-proteins, gave similar results. Both mastoparan and CCK induced turnover of inositol phosphates, at concentrations higher than necessary to induce oscillations.

Topics: Alkaloids; Animals; Calcium; Cholecystokinin; Cytosol; In Vitro Techniques; Inositol Phosphates; Intercellular Signaling Peptides and Proteins; Kinetics; Male; Microscopy, Fluorescence; Pancreas; Peptides; Protein Kinase C; Rats; Sodium Fluoride; Staurosporine; Tetradecanoylphorbol Acetate; Time Factors; Wasp Venoms