AIMS/HYPOTHESIS: Moderate disturbances of learning and memory were recognized as a complication of diabetes mellitus in patients. The streptozotocin-diabetic rat, an animal model of insulin-dependent diabetes, shows impairments in spatial memory and in long-term potentiation expression. We have studied the effect of experimental diabetes on expression of post-synaptic glutamate N-Methyl-D-Aspartate ionotropic receptors and of other key proteins regulating synaptic transmission at the post-synaptic compartment. METHODS: In situ hybridization and Western blot analysis were used to assess expression and protein concentration of N-Methyl-D-Aspartate receptors and alpha-calcium-calmodulin-dependent kinase II. Receptor subunits alphaCaMKII-dependent phosphorylation was studied in post-synaptic densities obtained from the hippocampus and cortex of control, streptozotocin-diabetic and insulin-treated rats. RESULTS: The transcript levels of NR1 and NR2A subunits of N-Methyl-D-Aspartate were unchanged in rats with a diabetic duration of 3 months when compared with age-matched control rats. Accordingly, NR1 and NR2A as well as GluR1, GluR2/3, PSD-95 and alphaCaMKII protein concentrations in post-synaptic densities were the same in both control and diabetic rats, whereas the immunoreactivity for NR2B was reduced by about 40%. In addition, the activity of alphaCaMKII on exogenous substrates, such as syntide-2, and the phosphorylation of NR2A/B subunits of N-Methyl-D-Aspartate receptor was reduced in hippocampal post-synaptic densities of streptozotocin-diabetic rats as compared with control rats. Furthermore, we show that insulin intervention for 3 months after diabetic duration partially restored both alphaCaMKII activity and NR2B levels. CONCLUSION/ INTERPRETATION: N-Methyl-D-Aspartate receptor expression and phosphorylation is possibly involved in behavioural and electrophysiological abnormalities observed in streptozotocin-diabetic rats.
AIMS/HYPOTHESIS: Moderate disturbances of learning and memory were recognized as a complication of diabetes mellitus in patients. The streptozotocin-diabeticrat, an animal model of insulin-dependent diabetes, shows impairments in spatial memory and in long-term potentiation expression. We have studied the effect of experimental diabetes on expression of post-synaptic glutamate N-Methyl-D-Aspartate ionotropic receptors and of other key proteins regulating synaptic transmission at the post-synaptic compartment. METHODS: In situ hybridization and Western blot analysis were used to assess expression and protein concentration of N-Methyl-D-Aspartate receptors and alpha-calcium-calmodulin-dependent kinase II. Receptor subunits alphaCaMKII-dependent phosphorylation was studied in post-synaptic densities obtained from the hippocampus and cortex of control, streptozotocin-diabetic and insulin-treated rats. RESULTS: The transcript levels of NR1 and NR2A subunits of N-Methyl-D-Aspartate were unchanged in rats with a diabetic duration of 3 months when compared with age-matched control rats. Accordingly, NR1 and NR2A as well as GluR1, GluR2/3, PSD-95 and alphaCaMKII protein concentrations in post-synaptic densities were the same in both control and diabeticrats, whereas the immunoreactivity for NR2B was reduced by about 40%. In addition, the activity of alphaCaMKII on exogenous substrates, such as syntide-2, and the phosphorylation of NR2A/B subunits of N-Methyl-D-Aspartate receptor was reduced in hippocampal post-synaptic densities of streptozotocin-diabeticrats as compared with control rats. Furthermore, we show that insulin intervention for 3 months after diabetic duration partially restored both alphaCaMKII activity and NR2B levels. CONCLUSION/ INTERPRETATION:N-Methyl-D-Aspartate receptor expression and phosphorylation is possibly involved in behavioural and electrophysiological abnormalities observed in streptozotocin-diabeticrats.
Authors: Derek A Costello; Marc Claret; Hind Al-Qassab; Florian Plattner; Elaine E Irvine; Agharul I Choudhury; K Peter Giese; Dominic J Withers; Paola Pedarzani Journal: PLoS One Date: 2012-02-27 Impact factor: 3.240
Authors: Ana R Santiago; Joana M Gaspar; Filipa I Baptista; Armando J Cristóvão; Paulo F Santos; Willem Kamphuis; António F Ambrósio Journal: Mol Vis Date: 2009-08-17 Impact factor: 2.367