Figure 1.

A schematic diagram of synaptic organization in hypocretin neurons. (A) Hypocretin-containing cell bodies are predominantly innervated by excitatory but not inhibitory synapses. There are more excitatory (glutamatergic) synapses than inhibitory (GABAergic) synapses on hypocretin-containing cell bodies. (B) The AMPA receptor (AMPAR)-carried excitatory postsynaptic current (EPSC) is significantly larger than NMDA receptor (NMDAR)-carried EPSC in hypocretin neurons, suggesting that a dominating number of AMPARs [including GluR2-lacking, calcium permeable AMPARs (Cp-AMPARs)] are expressed in hypocretin neurons.