The effects of elevated potassium on sympathetic ganglion cells in culture.

Abstract

Effects of a high potassium (40 mM) medium on the survival and differentiation of sympathetic ganglion cells from chick embryos were studied in dissociated cell culture. In the high potassium medium, survival of the sympathetic ganglion neurons was improved and catecholamine fluorescence of the nerve fibers increased with several days in culture, while acetylcholinesterase activity was slightly positive. In contrast, in the control medium, catecholamine fluorescence was only faintly observed, while acetylcholinesterase became strongly positive. Catecholamine fluorescence was intensified by increasing the potassium concentration in a medium, while it was diminished by reversing the potassium level back to the normal one. The effect of the high potassium medium on catecholamine fluorescence was reduced by Ca++ influx inhibitors, diltiazem or Mg.++ It is suggested that the high potassium medium increased the survival rate and prevented the sympathetic neurons from becoming cholinergic and allowed them to develop their adrenergic properties presumably through an increased level of the intracellular Ca++ due to Ca++ entry. sympathetic ganglion ; potassium ; cell culture ; differentiation Membrane potential is known to be an important factor involved in the mechanism and regulation of neuronal transmission. A question remains, however, if it has any trophic effects on neurons themselves. It has been shown that chronic depolarization of the cell membrane by an elevated extracellular potassium (K+) level increases the number of surviving neurons in culture of several cells, such as cerebellar neurons, ciliary ganglion neurons and dorsal root ganglion neurons

Perikaryal Myelination of Cultured Chick Embryo Statoacoustic Ganglion Cells: an Electron Microscopic Study

“…They were cultured on a collagen-coated cover glass in a humidified 3% CO 2 , 97% air atmosphere at 36°C. The culture medium consisted of 80% Eagle's MEM, 10% chick embryo extract and 10% horse serum, and it was changed every 3 days (13,14). Developments of the SAG cells were observed with a phase-contrast microscope.…”