Figure 2

Schematic representation of the glutamatergic and GABAergic receptors in a CA1 pyramidal neuron. The left box represents a CA3-CA1 synapse. The CA3 axon (orange) releases glutamate from the presynaptic terminals. The postsynaptic CA1 neuron expresses three types of glutamatergic receptors: metabotropic receptor (mGluR), alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR), and N-methyl-D-aspartate receptor (NMDAR). The AMPARs are represented in their active state, as they allow Na⁺ to enter onto the dendritic spine. The NMDARs are represented both in the closed state (leftmost NMDAR, with the Mg²⁺ block seen as a red ball in the mouth of the receptor) and in the open state, when the NMDARs allow Ca²⁺ to enter onto the spine (notice the absence of the Mg²⁺ block). The right box represents a synapse between an inhibitory interneuron and the CA1 cell. The interneuron releases γ-aminobutyric acid (GABA) onto the CA1 pyramidal neuron, which expresses GABA_A receptors (yellow) and GABA_B receptors (gray), leading to inhibition of the target cell. The GABA_A receptors are represented in the open state when they allow Cl^- to enter onto the CA1 dendrite.