The hippocampus, a medial temporal lobe structure
necessary for the formation of spatial memory, is
particularly affected by both normal and pathologic
aging impairment In rats as in humans, learning and memory
performance declines with age which makes this rodent
species a suitable model to evaluate therapeutic
strategies of potential clinical value for restoring agerelated
cognitive deficits. In previous studies we have
reported that hypothalamic or intracerebroventricular
insulin-like growth factor-I (IGF-I) gene therapy is able
to reverse or at least attenuate the lactotrophic,
reproductive and motor derangements of aging female
rats and are now interested in assessing
the restorative potential of this intervention on the spatial
memory performance of aging female rats. In most
rodent studies, spatial memory has been assessed using
the Morris Water Maze for which a
considerable performance database is available both for
rats and mice. Most rat studies on the impact of aging
on spatial memory have been performed in males (some
relevant studies are a fact that makes it difficult to establish
eventual sex-related differences in the impact of aging on
cognitive performance. A potential disadvantage of the
MWM in aging studies is that it requires a substantial
degree of physical fitness. This has led some investigators
to prefer the less physically demanding Barnes maze especially for aged rats. In both tests, rats learn to use spatial cues to guide them to a hidden platform
or tunnel. While the MWM involves immersion in water, a stimulus that provokes considerable corticosterone and corticotropin release in the Barnes maze animals are placed on an open, unprotected circular platform for them to walk in search
of the escape tunnel. Comparison between the Barnes maze and MWM in mice has shown that the latter induces higher circulating corticosterone concentration than the
former and that serum corticosterone levels show an inverse correlation with the performance of the animals in the MWM but not in the Barnes maze Furthermore, even at the tepid temperatures typically used in MWM studies, swim stress also causes
sympathetic activation and peripheral adrenaline release,especially in aged rats In order to generate a reference framework for future
therapeutic investigations in female rats, in the present
study we undertook to characterize the changes in
spatial memory in old and very old (senescent) females
using a modified version of the Barnes maze so that
nonspecific exploration and target-seeking activity as
well as the ability for acquisition and retention of spatial
information can be compared in the different age
groups. A set of relevant hippocampal cell markers was
also quantitated in the animals by means of an
unbiased stereological approach.
ฮิบโปโครงสร้างตรงกลางกลีบขมับที่จำเป็นสำหรับการก่อตัวของหน่วยความจำเชิงพื้นที่จะได้รับผลกระทบโดยเฉพาะอย่างยิ่งทั้งปกติและพยาธิวิทยาจากการด้อยค่าริ้วรอยในหนูที่เป็นมนุษย์ในการเรียนรู้และความจำประสิทธิภาพการทำงานลดลงตามอายุที่ทำให้หนูนี้ชนิดรูปแบบที่เหมาะสมในการประเมินผลการรักษากลยุทธ์ของมูลค่าทางคลินิกที่มีศักยภาพสำหรับการเรียกคืน ขาดดุลองค์ The hippocampus, a medial temporal lobe structure
necessary for the formation of spatial memory, is
particularly affected by both normal and pathologic
aging impairment In rats as in humans, learning and memory
performance declines with age which makes this rodent
species a suitable model to evaluate therapeutic
strategies of potential clinical value for restoring agerelated
cognitive deficits. In previous studies we have
reported that hypothalamic or intracerebroventricular
insulin-like growth factor-I (IGF-I) gene therapy is able
to reverse or at least attenuate the lactotrophic,
reproductive and motor derangements of aging female
rats and are now interested in assessing
the restorative potential of this intervention on the spatial
memory performance of aging female rats. In most
rodent studies, spatial memory has been assessed using
the Morris Water Maze for which a
considerable performance database is available both for
rats and mice. Most rat studies on the impact of aging
on spatial memory have been performed in males (some
relevant studies are a fact that makes it difficult to establish
eventual sex-related differences in the impact of aging on
cognitive performance. A potential disadvantage of the
MWM in aging studies is that it requires a substantial
degree of physical fitness. This has led some investigators
to prefer the less physically demanding Barnes maze especially for aged rats. In both tests, rats learn to use spatial cues to guide them to a hidden platform
or tunnel. While the MWM involves immersion in water, a stimulus that provokes considerable corticosterone and corticotropin release in the Barnes maze animals are placed on an open, unprotected circular platform for them to walk in search
of the escape tunnel. Comparison between the Barnes maze and MWM in mice has shown that the latter induces higher circulating corticosterone concentration than the
former and that serum corticosterone levels show an inverse correlation with the performance of the animals in the MWM but not in the Barnes maze Furthermore, even at the tepid temperatures typically used in MWM studies, swim stress also causes
sympathetic activation and peripheral adrenaline release,especially in aged rats In order to generate a reference framework for future
therapeutic investigations in female rats, in the present
study we undertook to characterize the changes in
spatial memory in old and very old (senescent) females
using a modified version of the Barnes maze so that
nonspecific exploration and target-seeking activity as
well as the ability for acquisition and retention of spatial
information can be compared in the different age
groups. A set of relevant hippocampal cell markers was
also quantitated in the animals by means of an
unbiased stereological approach.
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