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Zusammenfassung: <jats:title>Abstract</jats:title><jats:p>In animal models of diabetes mellitus, such as the streptozotocin‐diabetic rat (STZ‐rat), spatial learning impairments develop in parallel with a reduced expression of long‐term potentiation (LTP) and enhanced expression of long‐term depression (LTD) in the hippocampus. This study examined the time course of the effects of STZ‐diabetes and insulin treatment on the hippocampal post‐synaptic glutamate <jats:italic>N</jats:italic>‐methyl‐<jats:sc>d</jats:sc>‐aspartate (NMDA) receptor complex and other key proteins regulating hippocampal synaptic transmission in the post‐synaptic density (PSD) fraction. In addition, the functional properties of the NMDA‐receptor complex were examined. One month of STZ‐diabetes did not affect the NMDA receptor complex. In contrast, 4 months after induction of diabetes NR2B subunit immunoreactivity, CaMKII and Tyr‐dependent phosphorylation of the NR2A/B subunits of the NMDA receptor were reduced and αCaMKII autophosphorylation and its association to the NMDA receptor complex were impaired in STZ‐rats compared with age‐matched controls. Likewise, NMDA currents in hippocampal pyramidal neurones measured by intracellular recording were reduced in STZ‐rats. Insulin treatment prevented the reduction in kinase activities, NR2B expression levels, CaMKII–NMDA receptor association and NMDA currents. These findings strengthen the hypothesis that altered post‐synaptic glutamatergic transmission is␣related to deficits in learning and plasticity in this animal model.</jats:p>
Umfang: 438-447
ISSN: 0022-3042
1471-4159
DOI: 10.1046/j.0022-3042.2001.00713.x