title: The effect of elevated potassium on the time course of neuron survival in cultures of dissociated dorsal root ganglia.
abstract: The effect of potassium (K+) on the time course of neuron survival has been investigated by counting neurons over a 24-day period in live cultures of dissociated dorsal root ganglia from embryonic chick, fetal and newborn mouse, and fetal human material. In both normal K (6 mM) and in elevated K (20 mM mouse and human, 40 mM chick) there was initially a rapid exponential decrease in neuron survival. However, the magnitude of this decrease was less in the elevated K. In normal K neuron number decreased monotonically; the rate of degeneration itself decreased with time so that after 24 days neuron survival became relatively constant. In contrast, in elevated K the neuron number actually increased over a limited time interval before attaining a stable long-term value much greater than that in normal K. Thus, elevated K enhanced long-term survival by causing a lower rate of degeneration and also by causing an increase in neuron number during a limited period of the time in culture. From these observations and other evidence, it is argued that K can substitute to some extent for the trophic action normally exerted by the peripheral field of innervation of the DRG. It is further argued that K acts through its depolarizing effect on the membrane potential and that modification of intracellular ionic concentrations seems less likely to be involved.
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002470:Cell Survival / Q000187:drug effects; D002642:Chick Embryo; D003470:Culture Media; D046508:Culture Techniques; D005727:Ganglia, Spinal / Q000166:cytology* / Q000187:drug effects / Q000196:embryology; D006801:Humans; D051379:Mice; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D011188:Potassium / Q000494:pharmacology*; D013045:Species Specificity
chemical_list: D003470:Culture Media; D011188:Potassium