Roles of GSK3b in Odor Habituation and Spontaneous Neural Activity of the Mouse Olfactory Bulb

Glycogen synthase kinase 3b (GSK3b), a multifaceted kinase, is abundantly expressed in the brain, including the olfactory bulb (OB). In resting cells, GSK3b is constitutively active, and its over-activation is presumably involved in numerous brain diseases, such as Alzheimer’s disease. However, the functions of the constitutively active GSK3b in the adult brain under physiological conditions are not well understood. Here, we studied the possible functions of GSK3b activity in the OB. Odor stimulation, or blockade of peripheral olfactory inputs caused by either transgenic knock-out or ZnSO4 irrigation to the olfactory epithelium, all affected the expression level of GSK3b in the OB. When GSK3b activity was reduced by a selective inhibitor, the spontaneous oscillatory activity was significantly decreased in the granule cell layer of the OB. Furthermore, local inhibition of GSK3b activity in the OB significantly impaired the odor habituation ability. These results suggest that GSK3b plays important roles in both spontaneous neural activity and odor information processing in the OB, deepening our understanding of the potential functions of the constitutively active GSK3b in the brain under physiological conditions