Neurons in a developing embryo respond to changes in their own electrical activity by altering the types of chemical messengers that they produce, a new study suggests. This finding counters the traditional scientific view that genes alone determine which neurotransmitters a brain cell synthesizes.
A team led by Laura N. Borodinsky and Nicholas C. Spitzer, both of the University of California, San Diego, first measured distinctive patterns of electrical activity in each of four types of embryonic neurons in the spinal cords of frogs. The researchers then changed the electrical activity in such cells in other frog embryos by genetically engineering them to pass either more or less current through their membranes.
Those alterations that led to boosts in electrical activity also led to a surge in the number of cells producing inhibitory neurotransmitters that slow down neurons . Conversely, changes that caused electrical activity to decline triggered a rise in the number o