Jun 10, 2002
NEW YORK (Reuters Health) - Researchers working with retinal ganglion cells of neonatal rats have discovered that early in development, amacrine cells trigger the irreversible loss of axon growth. The finding appears in the June 7th issue of Science.
"These CNS neurons undergo a developmental switch in their intrinsic ability to extend axons; specifically, they switch from being good at growing axons to being good at growing dendrites", Dr. Jeffery L. Goldberg, told Reuters Health.
In a series of experiments with retinal ganglion cells from neonatal rat retinas, Dr. Goldberg and colleagues from Stanford University School of Medicine, California, found that amacrine cells signal the retinal ganglion cells to stop the growth of axons. At the same time, retinal maturation triggers retinal ganglion cells to increase dendritic growth.
"Because this switch in growth mode appears to be irreversible and occurs neonatally, concurrent with the loss of regenerative ability observed in vivo, we propose that it is an important contributor to the failure of central nervous system (CNS) neurons to regenerate in vivo," Dr. Goldberg and colleagues comment.
If the same switch does occur in other CNS neurons, it may have implications for the treatment of brain or spinal cord injury. "It may provide a novel strategy, specifically to target the neuron's intrinsic growth ability and try to revert adult neurons to their earlier rapid growth ability, as a way towards effective, rapid regeneration after injury," Dr. Goldberg said. "Of course, any clinical benefit is still remote--much basic science remains to be done."
In a journal editorial, Drs. Lisa McKerracher and Benjamin Ellezam from the Universit de Montr al comment, "The Goldberg et al. work suggests that a better understanding of the developmental switch from axonal to dendritic growth may hold the key to regeneration in the CNS."
Science 2002;296:1860-1864. http://www.sciencemag.org.
© 2002 Reuters Ltd