Journal de la maladie d'Alzheimer et du parkinsonisme

Abstrait

Morphofunctional Correlation of Excitatory and Depressor Synaptic Processes in Hippocampus, Amygdala and Basal Meynert Nucleus Neurons in Dynamics of Development of Alzheimer's Disease Model Induced by Aβ25-35

Sarkissian JS, Minasyan AL, Sahakyan KT, Danielyan MH, Stepanyan HY, Poghossyan MV and Sarkisian VH

Objective: Compensatory mechanisms are responsible for the clinical signs of suppression of neurodegeneration. Intervention into their mechanisms on an example of the ratio of excitatory and depressor synaptic responses will contribute to the development of therapeutic strategies.
Methods: After 12-28 weeks (w) of experiment on the model of Alzheimer’s disease (AD), an activity of single neurons of hippocampus (H), Amygdala (Am) and, nucleus basalis of Meynert (NBM) to high frequency stimulation (HFS) of entorhinal cortex (EC) was recorded. The high frequency stimulation of H resulted in an activity of single neurons of the Am and NBM. By means of on-line selection and special mathematical analysis, tetanic potentiation (TP) and depression (TD) with further combination into posttetanic uni and multidirectional sequences, were revealed. In morpho- and histochemical study, the method of revelation of Сa²⁺- dependent phosphorylation was used.
Results: After 12 weeks of experiment on the model of AD, a heavy TD of NBM and Аm neurons to HFS of H, as well as a weak (TD) in H and NBM neurons to HFS of EC were found. TP occurred by the activation of ЕС in the H (TP PTP) and in Am (TP PTD) neurons, equal to and above the norm in neurons of Am to HFS of H. In the neurons of NBM to HFS of EC, the weakest excitation to HFS of H was detected. In the neurons H to HFS of EC, Am and NBM to HFS of H, after 13-28 weeks, TD and tetanic excitation in all cases were low, which indicating on depletion of compensatory opportunities. Morpho- and histo-chemical changes of H, Am and NBM neurons on the model of AD were characterized by total tendency to structural-metabolic dysfunctions, with distortion of forms, central chromatolysis, presence of light ectopic nucleus with increased nucleolus, change reaction of neurofibrills, lack of reaction processes, accumulation of hyper phosphorylated entities and, presence of spaces with the lack of cellular reaction.
Conclusion: The absence of expressed depression, presupposed by us as a protector in the present study, makes it necessary to involve pharmacological interventions with a view to its strengthening, and therefore is the subject of the next reports. Electrophysiological data have been confirmed morphologically.