Figure 1: Neural networks, classical neurotransmitters and neuropeptides involved in major depression. Alpha1AR: alpha-1A receptor, a subreceptor of the noradrenergic receptor; CRH: corticotropin-releasing hormone; CRH1R: CRH-1 receptor, a subreceptor of the CRH receptor; DA: dopamine; D2R: D2 receptor: a subreceptor of the dopaminergic receptor; GABA: gamma-aminobutyric acid; GABAAR: GABAA receptor: a subreceptor of the GABAergic receptor; GABABR: GABAB receptor: a subreceptor of the GABAergic receptor; Glu: glutamate; 5-HT: serotonin; 5-HT1AR: 5-HT1A receptor: a subreceptor of the serotonergic receptor; 5-HT2CR: 5-HT2C receptor: a subreceptor of the serotonergic receptor; m5GluR: m5Glu receptor: a subreceptor of the metabotropic glutaminergic receptor; MD: major depression; NA: noradrenalin; NMDAR: N-methyl-Daspartate receptor. A plus mark indicates a postsynaptic excitatory impulse, and a minus mark indicates a presynaptic inhibitory impulse. The arrow upwards denotes increase, and the arrow downwards denotes decrease.