Skip to main content
. Author manuscript; available in PMC: 2010 Jan 1.
Published in final edited form as: Brain Dev. 2008 May 19;31(1):1–10. doi: 10.1016/j.braindev.2008.03.014

Figure 2.

Figure 2

Diagram of the three major types of excitatory neurotransmitter receptors for glutamate. NMDA receptors are activated when glutamate (glu) and glycine (gly) both occupy receptor sites and the membrane depolarizes, allowing magnesium (Mg++) to leave the channel. Relief of the magnesium block allows calcium and sodium to pass through the channel. Most fast excitatory activity in the brain is mediated by AMPA receptor channels, which flux mostly sodium, but channels lacking the GluR2 subunit also pass calcium. In contrast to NMDA and AMPA receptors, metabotropic glutamate receptors are not linked to ion channels but to G proteins and second messenger systems such as phosphoinositide turnover that regulate intracellular calcium levels and protein translation.