RAC1 and Alzheimer disease: Moreover, hippocampal Rac1 is activated in 6-week-old 3xTg-AD mice and total protein levels are reduced at 7 months, but the intranasal administration of constitutively active Rac1 peptides in 6.5-months-3xTg-AD mice inhibits dendritic spine loss and rescues spine and synaptic abnormalities [155].