TY - JOUR T1 - Embryonically Expressed GABA and Glutamate Drive Electrical Activity Regulating Neurotransmitter Specification JF - The Journal of Neuroscience JO - J. Neurosci. SP - 4777 LP - 4784 DO - 10.1523/JNEUROSCI.4873-07.2008 VL - 28 IS - 18 AU - Cory M. Root AU - Norma A. Velázquez-Ulloa AU - Gabriela C. Monsalve AU - Elena Minakova AU - Nicholas C. Spitzer Y1 - 2008/04/30 UR - http://www.jneurosci.org/content/28/18/4777.abstract N2 - Neurotransmitter signaling in the mature nervous system is well understood, but the functions of transmitters in the immature nervous system are less clear. Although transmitters released during embryogenesis regulate neuronal proliferation and migration, little is known about their role in regulating early neuronal differentiation. Here, we show that GABA and glutamate drive calcium-dependent embryonic electrical activity that regulates transmitter specification. The number of neurons expressing different transmitters changes when GABA or glutamate signaling is blocked chronically, either using morpholinos to knock down transmitter-synthetic enzymes or applying pharmacological receptor antagonists during a sensitive period of development. We find that calcium spikes are triggered by metabotropic GABA and glutamate receptors, which engage protein kinases A and C. The results reveal a novel role for embryonically expressed neurotransmitters. ER -