Endocrine Abstracts

Bilateral ovariectomy (OVX) in female rats cause neurodegeneration in the nervous system of rodents and imitates systemic disorders in postmenopausal women’s organism. Synaptic modulation by estrogen is essential to understand the molecular mechanisms of estrogen replacement therapy. The aim of present work was to determine the action of Sinestrol on rats’ hippocampal synaptic transmission, plasticity and cell survival in condition of bilateral OVX. Electrophysiological and morphohistochemical (by revealing Ca²⁺-dependent acid phosphatase) studies by extracellular recording of hippocampal single-neuronal spike activity under high-frequency stimulation (HFS) of entorhinal cortex (EC) were performed on: 1) intact Albino rats, 2) after 8 week of OVX (placebo-control), 3) after 8 week of OVX (after 3 weeks i.m. injection of Sinestrol- 0.1 ml 2%). Our data suggest that OVX reduces hippocampal synaptic activity and failures the balance of excitatory and inhibitory responses of norm. After 8 week following OVX in hippocampal neurons dominate effects of tetanic depression in combination with posttetanic potentiation (45%) in response to HFS EC and typical of presence of areactive neurons (21%). Sinestrol promote the reorganization of neuronal circuitries of cortex-hippocampus by modulation of anomalous synaptic activity, as well as the balance of areactive and reactive units. Morphohistochemical analysis of studies by revealing Ca²⁺-dependent acid phosphatase testify that in whole Sinestrol enhances phosphorylation processes providing optimization of regeneration process following OVX.