SST and Alzheimer disease: However, this may not be true in AD because GABAergic neurons in the dentate gyrus are vulnerable in AD, especially the so-called HIPP cells that co-localize neuropeptide Y (Chan-Palay et al., 1986; Loreth et al., 2012; Albuquerque et al., 2015) and somatostatin (Rossor et al., 1980; Chan-Palay, 1987; Ramos et al., 2006).