MORPHOLOGICAL AND ELECTROPHYSIOLOGICAL CHARACTERISTICS OF DISSOCIATED CHICK EMBRYONIC SPINAL GANGLION CELLS IN CULTURE

Previous electrophysiological studies of cultured neurons have utilized explants of intact fragments of nervous tissue. In the present study 10-day chick embryo spinal ganglia were dissociated into single cells before culturing thus disrupting the normal tissue integrity. The dissociated cells were cultured by a method which permitted their maintenance for longer periods (7 weeks) and greater morphological development than reported previously. The non-neural cells proliferated and formed a multilayered connective tissue sheet. The neurons became established on the surface of this sheet and regenerated nerve fibers which travelled both over the surface and in the extracellular substance of the sheet. Fasciculation of the nerve fibers was common. These cultures were maintained in a liquid medium. This along with other technological improvements (including the use of an inverted microscope) greatly facilitated the electrophysiological investigation. Resting potentials were recorded from 322 neurons which had been maintained in culture for 5 weeks. Over 80% of these neurons had potentials in the range 40-55 mv. Of 71 neurons stimulated electrically, 44 generated action potentials similar to those recorded previously from cultured whole ganglia. The seven values of conduction velocity obtained for the regenerated nerve fibers ranged from 0.12 to 0.58 m/sec. From these morphological and electrophysiological observations it is concluded that the disruption of the original tissue integrity does not preclude the expression of both cytotypic and histotypic signs of normal neural differentiation. © 1969.