Cytosolic free magnesium concentration in human platelets

Abstract

Although the magnesium ion (Mg 2+) is considered to play an important role in cell activation, information is limited by the lack of suitable methods for measuring cytosolic free Mg 2+ concentration ([Mg 2+]i). We measured [Mg 2+]i in resting and activated human platelets using a new fluorescent Mg 2+-indicator, mag-fura-2. [Mg 2+]i was 0.54±0.14 mM in resting platelets from 15 healthy volunteers. [Mg 2+]i was elevated to 1.33±0.44 mM and 0.92±0.37 mM in platelets stimulated with thrombin and collagen, respectively. Increased Mg 2+ was considered to be derived chiefly from intracellular Mg 2+ mobilization. These results suggest that platelet activation is associated with the increase in [Mg 2+]i. The estimation of [Mg 2+]i using this method is usefull for the investigation of mechanism for various cell activation.