Search results for "Embryonic heart"
showing 3 items of 3 documents
Patterns of Reversal in the Heart of Ciona Intestinalis L.
1969
The reversal of the heart beat is not exclusive to tunicates, for Marcello Malpighi in 1660 described periodic reversal in Bombyx mori and in some Orthoptera. In 1821 Kuhl and van Hasselt reported the phenomenon in Ciona intestinalis L. We have observed reversal in many active pulsating blood vessels, both in vertebrates and in invertebrates, and even in embryonic heart tubes. Using four or five suction electrodes simultaneously, we were able to record electrical activity from multiple sites. Normally, the contraction wave originates from a localized site at one end of the tube and then traverses the whole length of the heart. When a wave of excitation does not propagate the full length, th…
Myogenesis and contraction in the early embryonic heart of the rainbow trout
1977
Myogenesis in the embryonic heart of the rainbow trout, Salmo galrdneri (Rich.), was investigated electron microscopically from the 29th to the 41st somite stage. Thick and thin myofilaments are formed simultaneously as well as precursors of Z-lines, to which the thin filaments are attached. The genesis of filaments takes place in the region around the intracellular yolk droplets. The first myofibrils appear by the 33rd somite stage, probably formed by a mechanism of self-assembly in which the binding sites of actin and myosin participate. A- and I-bands do not develop before the 38th somite stage. The contraction already begins during the 33rd somite stage in the middle of the tubular hear…
Primary culture of avian embryonic heart forming region cells to study the regulation of vertebrate early heart morphogenesis by vitamin A
2014
Background: Important knowledge about the role of vitamin A in vertebrate heart development has been obtained using the vitamin A-deficient avian in ovo model which enables the in vivo examination of very early stages of vertebrate heart morphogenesis. These studies have revealed the critical role of the vitamin A-active form, retinoic acid (RA) in the regulation of several developmental genes, including the important growth regulatory factor, transforming growth factor-beta2 (TGFβ2), involved in early events of heart morphogenesis. However, this in ovo model is not readily available for elucidating details of molecular mechanisms determining RA activity, thus limiting further examination o…