NPAS4 and Brain atrophy: L-theanine intake (6 mg/kg) could prevent brain atrophy and stress vulnerability in senescence-accelerated mice prone 10 (SAMP10) mice, with the mechanism of intaking L-theanine could block the expression changes of the transcription factor neuronal PAS domain protein 4 (Npas4) and Lipocalin 2 (Lcn2) in hippocampus and PFC of SAMP10 (58).