The Allergic Response of Rabbit Platelets

[摘要] The allergic response of rabbit platelets as observed by increased membrane permeability to 86Rb and by histamine release is Mg++-dependent. There is competitive inhibition by Ca++ at optimal levels of Mg++ (1 to 3 × 10-4 M). Calcium can substitute for Mg++ at suboptimal levels of the latter, but is less effective. Calcium increases the range of Mg++ levels for an optimal response, possibly by stabilizing a reaction intermediate. The latent period for 86Rb efflux is brought to a minimum of about 1 min, by optimal Mg++ concentrations. The minimal latent period for histamine release is about 5 min. The initial rate is inhibited by excess Mg++. The latent period is far less responsive in this respect.The data suggest that increased membrane permeability and histamine release are successive steps in the allergic response of platelets, in which only a Mg++ requirement has been identified.

[学科分类] 生物科学（综合）