NR3C1 and Alzheimer disease: In addition, apelin-13 has shown anxiolytic effects in rat models of AD treated with Aβ25-35, possibly via upregulating the expression of the glucocorticoid receptor (GR) and downregulating those ofFK506 binding protein 51 (FKBP5), which play a pivotal role in the regulation of the HPA axis [120].