Intracellular Calcium Ion Elevation in Chicken Phagocytes Treated with Activating Agents

Abstract

Cytoplasmic calcium ion concentrations [Ca2+]i were measured for the first time in chicken heterophils and macrophages stimulated with Leukotriene B4 (LTB4), phorbol myristate acetate (PMA), formyl-methionyl-leucyl-phenylalanine (fMLP) and lipopolysaccharide (LPS) which are known to be activating factors of phagocyte functions. [Ca2+]i in rat neutrophils and macrophages was also measured after stimulation with these activating factors. [Ca2+]i was measured by the Fura-2-AM-loading method using an intracellular ion analyzer. Resting levels of [Ca2+]i in chicken phagocytes were similar to those reported previously in rats. [Ca2+]i of chicken phagocytes was elevated by treatment with LTB4, PMA and LPS, and the patterns and duration times of the elevation of [Ca2+]i by these factors resembled those in rat phagocytes. However, fMLP did not elevate [Ca2+]i in chicken phagocytes, although the agent elevated [Ca2+]i of rat phagocytes. The degree of elevation of [Ca2+]i in chicken heterophils and macrophages stimulated by LTB4, PMA and LPS was significantly higher than that in the same kinds of rat phagocytes (neutrophils and macrophages) stimulated with the corresponding factors. The degree of elevation of [Ca2+]i in granulocytes treated with these factors was significantly higher than that in macrophages in chickens and rats. The reasons for these differences are unclear at the present time. It is valuable to examine the reason for these differences.