title: Changes in Synaptic Plasticity and Glutamate Receptors in Type 2 Diabetic KK-Ay Mice.
abstract: In the present study, the progressive alteration of cognition and the mechanisms of reduction in long-term potentiation (LTP) in spontaneous obese KK-Ay type 2 diabetic mice were investigated. In the study, 3-, 5-, and 7-month-old KK-Ay mice were used. The results indicated that KK-Ay mice showed cognitive deficits in the Morris water maze test beginning at the age of 3 months. LTP was significantly impaired in KK-Ay mice during whole study period (3 to 7 months). The above deficits were reversible at an early stage (3 to 5 months old) by diet intervention. Moreover, we found the underlying mechanisms of LTP impairment in KK-Ay mice might be attributed to abnormal phosphorylation or expression of postsynaptic glutamate receptor subunits instead of alteration of basal synaptic transmission. The expression levels of NR1, NR2A, and NR2B subunits of N-methyl-d-aspartate receptors (NMDARs) were unchanged while the Tyr-dependent phosphorylation of both NR2A and NR2B subunits were significantly reduced in KK-Ay mice. The level of p-Src expression mediating this process was decreased, and the level of αCaMKII autophosphorylation was also reduced. Meanwhile, the GluR1 of α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs) was decreased, and GluR2 was significantly increased. These data suggest that deficits in synaptic plasticity in KK-Ay mice may arise from the abnormal phosphorylation of the NR2 subunits and the alteration of subunit composition of AMPARs. Diet intervention at an early stage of diabetes might alleviate the cognitive deficits and LTP reduction in KK-Ay mice.
authors.forename: Huajing
authors.initials: H
authors.lastname: Yin
authors.forename: Weiping
authors.initials: W
authors.lastname: Wang
authors.forename: Wenwen
authors.initials: W
authors.lastname: Yu
authors.forename: Jiang
authors.initials: J
authors.lastname: Li
authors.forename: Nan
authors.initials: N
authors.lastname: Feng
authors.forename: Ling
authors.initials: L
authors.lastname: Wang
authors.forename: Xiaoliang
authors.initials: X
authors.lastname: Wang
mesh_terms: D000818:Animals; D003072:Cognition Disorders / Q000178:diet therapy / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000178:diet therapy / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000178:diet therapy / Q000378:metabolism*; D059305:Diet, High-Fat; D018450:Disease Progression; D006624:Hippocampus / Q000378:metabolism; D017774:Long-Term Potentiation / Q000502:physiology*; D008297:Male; D018782:Maze Learning / Q000502:physiology; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D009765:Obesity / Q000178:diet therapy / Q000378:metabolism*; D017470:Receptors, Glutamate / Q000378:metabolism*; D065852:Spatial Memory / Q000502:physiology; D046509:Tissue Culture Techniques
chemical_list: D017470:Receptors, Glutamate
keywords: AMPA receptor; KK-Ay mice; NMDA receptor; diabetic encephalopathy; long-term potentiation; type 2 diabetes mellitus