Flipping the switch from electrical to chemical communication

Abstract

Immature neurons in many brain regions are electrically coupled through gap junctions, which are lost as chemical synaptic transmission matures. This developmental uncoupling is now shown to require NMDA receptor activation.

Figure 1

NMDA receptor–mediated uncoupling of developing hypothalamic neurons. During synaptic circuit development in the medial hypothalamus and many other brain regions, the primary mode of neuronal communication switches from one based on gap junctions (left) to one based on chemical synapses (right). Arumugam and colleagues now show that downregulation of the neuronal gap-junction protein connexin36 (Cx36) and dye coupling (yellow) require activation of NMDA receptors, along with CaMKII/IV, PKC and CREB. In the intact brain, additional glutamatergic inputs are provided by other extrinsic sources.