Impact of L-Thyroxin on Allergic Vascular Constriction and Intracellular Calcium Modulating Mechanism

Objective:To investigate the changes of allergic vascular response in L-thyroxin treated guinea pig pathological model. Methods: L-thyroxin treated guinea pig pathological model was prepared as hyperthyroidism group. The allergic vascular constriction was induced by ovalbumin in vitro. In calcium-contained or -free medium and under drug's interference, the changes of allergic vascular constrictions in normal and hyperthyroidism groups and the dependence on either extracellular or intracellular calcium was observed. Results: The allergic vascular constrictions in two groups were mainly dependent on the intracellular calcium release and less on the extracellular calcium. The effect of the caffeine-sensitive intracellular calcium pool was most important, and the effect of the phenylephrine-sensitive intracellular calcium pool was less significant. Conclusion: An increase of the intracellular calcium release in hyperthyroidism group was more remarkable than that in normal group, which resulted mainly from increased intracellular calcium release from caffeine-sensitive calcium pool.