Many researchers have long been investigating the mechanism of actomyosin contraction. Actomyosin is an interesting macromolecular complex, which enables energy conversion that generates mechanical force very efficiently at a temperature compatible for animals. Vertebrate embryos gradually develop striated muscles, and the embryos can make various body movements by muscular contraction as early as at the late embryonic stage before hatching. In lower vertebrates, pulsation of the heart is also observable in late stage embryos. Here, we examined whether active contraction of actomyosin is necessary for normal morphogenesis of the embryonic/larval heart. Xenopus early larvae are very transparent, so they are suitable to observe the heart morphology and its contractile activities non-invasively. From such a viewpoint, the Xenopus larva is an ideal model organism. Thus, we first administered Blebbistatin, an inhibitor of actomyosin contraction, to Xenopus late stage embryos, and reared them until the early larval stage. As the results, hypoplasia of heart morphogenesis was frequently induced. As a next step, we intended to perform a comparable experiment; we administered Omecamtiv, a cardiotonic reagent, to potentiate the actomyosin contraction of the developing heart. Unexpectedly, Omecamtiv also induced a dwarf heart at a high frequency. Immunostaining using the antibody for muscles revealed that both Blebbistatin and Omecamtiv caused changes of fine structures of the heart. Based on these complementary experiments, we concluded that moderate contraction of actomyosin is essential for the normal asymmetric morphogenesis of the heart. Finally we report that Phenylhydrazine significantly induced hyperplasia of the heart, and fasciculation of the ventricular muscles was disordered after Phenylhydrazine treatment.
内容記述
原著
雑誌名
Science Journal of Kanagawa University
巻
33
ページ
67 - 79
発行年
2022-07-30
ISSN
1880-0483
書誌レコードID
AA12068302
著者版フラグ
publisher
出版者
神奈川大学総合理学研究所
Research Institute for Integrated Science, Kanagawa University
両生類アフリカツメガエルの心臓の形態形成におけるActomyosinの役割
09 両生類アフリカツメガエルの心臓の形態形成におけるActomyosinの役割
(4.11MB)
