Extracellular Electrical Currents in the Chick Blastoderm

Abstract

Extracellular electrical currents were recorded using a computer-controlled scanning vibrating electrode from gastrulating chick blastoderms cultured in vitro. On the ventral surface, currents of 10-20 µA/cm diverged from the area opaca and turned around the margin of blastoderm across the vitelline membrane. Weaker currents (1-10 µA/cm) converged to the anterolateral area pellucida and penetrated it in the ventrodorsal direction. On the dorsal surface, currents returned to the area opaca from the margin and from the center of area pellucida. During development, the pattern of currents remained similar on the dorsal surface while the leaky area on the ventral surface progressively extended to all the periphery of area pellucida. The intensity of currents in the blastoderm oscillated with a period of 5 to 6 min. This spatio-temporal organization of extracellular currents is compared to physiological activities of embryonic cells in different regions of the blastoderm.

Bioelectromagnetics in morphogenesis

“…Table 4 summarizes data showing that endogenous EM fields exist in a wide variety of developing systems and correlate with and predict spatio-temporal events in embryonic development. Developing systems generally drive steady ion currents and produce substantial fields within themselves; examples include currents that enter the prospective and continuing growth point of several tip growing plant cells, voltage across the cytoplasmic bridge between an insect oocyte and its nurse cell, current traversing a recently fertilized egg from animal to vegetal pole, and early potentials across embryonic Fields between egg-ovary systems drive materials into oocyte Hagiwara and Jaffe, 1979;Jaffe and Woodruff, 1979;Barish, 1983;Nuccitelli, 1983;Bohrmann et al, 1984;Kunkel, 1986Kunkel, , 1991Bowdan and Kunkel, 1990;Kindle et al, 1990;Diehl-Jones and Huebner, 1993;Anderson et al, 1994;Kunkel and Faszewski, 1995 Eggs drive currents around themselves Chambers and de Armendi, 1979;Robinson, 1979;Bohrmann et al, 1986a;Bowdan and Kunkel, 1990;Kindle et al, 1990;Coombs et al, 1992;Anderson et al, 1994;Kunkel and Smith, 1994;Kunkel and Faszewski, 1995;Faszewski and Kunkel, 2001 Mouse and chick embryos drive fields around themselves Burr and Hovland, 1937b;Kucera and de Ribaupierre, 1989;Hotary and Robinson, 1990;Keefe et al, 1995 Neural tube of amphibians generates large fields Nuccitelli, 1984;Hotary and Robinson, 1991 Plants drive a variety of fields which correlate with sites of growth and also predict growth rates and dimensions of final shape Burr, 1942Burr, , 1950…”

“…Fields between egg-ovary systems drive materials into oocyte Hagiwara and Jaffe, 1979;Jaffe and Woodruff, 1979;Barish, 1983;Nuccitelli, 1983;Bohrmann et al, 1984;Kunkel, 1986Kunkel, , 1991Bowdan and Kunkel, 1990;Kindle et al, 1990;Diehl-Jones and Huebner, 1993;Anderson et al, 1994;Kunkel and Faszewski, 1995 Eggs drive currents around themselves Chambers and de Armendi, 1979;Robinson, 1979;Bohrmann et al, 1986a;Bowdan and Kunkel, 1990;Kindle et al, 1990;Coombs et al, 1992;Anderson et al, 1994;Kunkel and Smith, 1994;Kunkel and Faszewski, 1995;Faszewski and Kunkel, 2001 Mouse and chick embryos drive fields around themselves Burr and Hovland, 1937b;Kucera and de Ribaupierre, 1989;Hotary and Robinson, 1990;Keefe et al, 1995 Neural tube of amphibians generates large fields Nuccitelli, 1984;Hotary and Robinson, 1991 Plants drive a variety of fields which correlate with sites of growth and also predict growth rates and dimensions of final shape Burr, 1942Burr, , 1950Burr and Sinnot, 1944;Burr and Nelson, 1946;Rosene and Lund, 1953;Stump et al, 1980;Miller and Gow, 1989;Wang et al, 1989;…”

Fibronectin distribution in the chick embryo during formation of the blastula

“…5, from stage X-XI to 6 HH) is accompanied by an increase in oxidative metabolism (Raddatz and Kucera 1983). Furthermore, the ECM in the AO becomes organized in space (Monnet-Tschudi et al 1985), and this supracellular arrangement takes place in parallel with the appearance of vectorial organization of specific cell functions such as mechanical activity (Kucera and Monnet-Tschudi 1987) and ionic transports (Kucera and de Ribaupierre 1989). The morphological and physiological data thus suggest that the supracellular arrangement of ECM and the functional differentiation of cells might modulate one another, and represent early intercellular communications in the blastoderm.…”