Interrelation and dynamic activity of visceral muscle and nerve cells from insect embryos in long-term cultures.

Abstract

AbstractMultiple segments of esophagus dissected out from 16‐day cockroach embryos were cultured in vitro in a chemically defined medium in the presence of dissociated nerve cells from the same donors. A first migratory wave of cells took place from the explants between the first and fourth week of culture. The morphological characteristics of these cells suggest that they originate from tracheolar cells. Between the second and fifth month of culture, a second migratory wave of a different cell type replaces the first wave of short‐living cells. These cells migrate out only after nerve fibers from the ingluvial ganglion have branched into the medium. They form long cellular ribbons and exhibit spontaneous contractility. The characteristics of the contractile cycles were examined at the inverted microscope, with Nomarski optics, and in time‐lapse cinematography. The cells were identified as myocytes and their origin traced to the longitudinal and circular muscle layer of the explants. The contratile cell ribbons establish firm contact with nerve fibers from the ingluvial ganglion, which in turn exhibit a vibratory motion identical to that of the cells. The most plausible interpretation is that nerve fibers are pushed and pulled by contractile myocytes. The results of these in vitro experiments show a strong affinity of myocytes for nerve fibers and bring to light a new aspect of the relationship between these cells and the visceral fibers which provide for their innervation.