Abstract:
BACKGROUND:Manipulating thyroid hormones has been shown to influence learning and memory. Although a large body of literature is available on the effects of thyroid hormone deficiency on learning and memory functions during developmental or adult-onset hypothyroidism, electrophysiological findings are limited. This limitation is especially notable with respect to thyroxine administration in adult, normothyroid animals. METHODS:Experiments were carried out on 12 adult male Wistar rats, each 9-10 months of age. Rats were randomly divided into hyperthyroid (0.2 mg/kg/day intraperitoneal thyroxine injection, for 21 days) and control groups (n = 6 animals in each group). Following spatial learning performance tests on hyperthyroid and control groups, rats were anesthetized with urethane and placed in a stereotaxic frame. A bipolar, tungsten electrode was used to stimulate the medial perforant path. A glass micropipette was inserted within the granule cell layer of the ipsilateral dentate gyrus to record field excitatory postsynaptic potentials (fEPSP). Following a 15-min baseline recording of fEPSPs, long-term potentiation (LTP) was induced by four sets of tetanic pulse trains. RESULTS:Thyroxine-treated rats showed significantly worse performance in the spatial memory task and attenuated input-output relationships in the electrophysiological analyses. Treated rats also showed a lower efficacy of LTP induction when compared with controls. CONCLUSION:The present study provides clear in vivo evidence for the action of L-thyroxine in the impairment of synaptic plasticity and in inducing spatial memory task deficits in adult rats. These findings may explain the complaints of cognitive function reductions in hyperthyroid patients.
journal_name
Neuroendocrinologyjournal_title
Neuroendocrinologyauthors
Taşkın E,Artis AS,Bitiktas S,Dolu N,Liman N,Süer Cdoi
10.1159/000328513subject
Has Abstractpub_date
2011-01-01 00:00:00pages
218-27issue
3eissn
0028-3835issn
1423-0194pii
000328513journal_volume
94pub_type
杂志文章abstract::Studies were conducted to determine if the hypothermic effects of barbiturates were responsible for their ability to suppress luteinizing hormone (LH) secretion in rats following ovariectomy or treatment with gonadal steroids. In both ovariectomized rats and rats treated with estradiol and progesterone, pentobarbital ...
journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124822
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journal_title:Neuroendocrinology
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doi:10.1159/000122925
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abstract::Tyrosine hydroxylase activity in noradrenergic neurons of the locus coeruleus was found to rise in bilaterally adrenalectomized adult mice, with maximum increase of the enzyme activity (52% above control) occurring 7 days after the surgery. No such increase of tyrosine hydroxylase activity was found in dopaminergic ne...
journal_title:Neuroendocrinology
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000123413
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journal_title:Neuroendocrinology
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journal_title:Neuroendocrinology
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000122659
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journal_title:Neuroendocrinology
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journal_title:Neuroendocrinology
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124081
更新日期:1985-03-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000124936
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journal_title:Neuroendocrinology
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doi:10.1159/000123200
更新日期:1981-07-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
doi:10.1159/000125724
更新日期:1991-03-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
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更新日期:1985-11-01 00:00:00
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journal_title:Neuroendocrinology
pub_type: 杂志文章
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journal_title:Neuroendocrinology
pub_type: 杂志文章
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更新日期:1986-01-01 00:00:00