Paper Information

Title:  PROTECTIVE ROLE OF ESTRADIOL ON HIPPOCAMPAL DENTATE GYRUS FIELD POTENTIALS IN AN EXPERIMENTAL ALZHEIMER’S DISEASE MODEL IN FEMALE RATS
Type: POSTER
Author(s): MOTAMEDI F.,PARVISHAN A.*
 
 *NEUROSCIENCE RESEARCH CENTER
 
Name of Seminar: IRANIAN CONGRESS OF PHYSIOLOGY AND PHARMACOLOGY
Type of Seminar:  CONGRESS
Sponsor:  PHYSIOLOGY AND PHARMACOLOGY SOCIETY, MASHHAD UNIVERSITY OF MEDICAL SCIENCE
Date:  2009Volume 19
 
 
Abstract: 

The protective role of estrogen in several areas has been proposed but there is a debate about the protective role of this hormone in hippocampus of Alzheimer’s disease (AD) patients. In the present study, by using an AD animal model, the possible protective role of estrogen was investigated on the hippocampal synaptic plasticity of female rats. Experimental AD was induced by bilateral injection of beta amyloid 1-42 in the dentate gyrus (DG) of female rats, and then learning and memory were tested using the passive avoidance task. Field potentials were recorded from DG. For induction of LTP, 200 Hz tetanic stimulation was used. Six days after removal of ovaries, 17- beta estradiol was subcutaneously injected twice in a 24h interval in order to assess the absence and supplementary effects of this substance. 48 hours after the second injection, DG field potentials, were recorded. Beta amyloid 1-42 disrupted the memory retention but not acquisition in the passive avoidance task. Beta amyloid had no effect on the baseline of field potentials but could significantly decrease the LTP of both population spikes (PS) and excitatory post-synaptic potentials (EPSP) in the intact and ovariectomized rats. On the other hand, presence and absence of estrogen had no effect on the LTP. However, estrogen could significantly reverse the destructive effect of beta amyloid 1-42 on the PS amplitude but had no effect on the slope of EPSP. It seems that the protective effect of estrogen is through the action potentials evoked in somatic region of hippocampal DG.

 
Keyword(s): ALZHEIMER’S DISEASE, BETA AMYLOID, ESTRADIOL, DENTATE GYRUS, LTP, SYNAPTIC PLASTICITY
 
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