NPY and Alzheimer disease: In harmony with this concept, several studies reported reduced numbers of GABAergic interneurons in the hippocampus of transgenic mouse models of AD and found profound changes in cells immunopositive for parvalbumin (PV+), somatostatin (SST+), calretinin (CR+), and neuropeptide Y (NPY+) (Ramos et al., 2006; Popović et al., 2008; Takahashi et al., 2010; Stanley et al., 2012; Albuquerque et al., 2015; Giesers and Wirths, 2020; Xu et al., 2020; Ali et al., 2023), while negative findings exist as well (e.g., Sos et al., 2020).