Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypothyroidism causes mental retardation secondary to changes in the organization of the CNS. These changes affect higher brain functions for which interhemispheric transfer of information is crucial. In present study, the anterior commissure (AC) and corpus callosum (CC) of normal (C) and hypothyroid (H) rats has been examined using quantitative electron microscopy. H rats received an antithyroid treatment with methimazole from embryonic day 14 (E14) and surgical thyroidectomy at postnatal day 6 (P6). In the AC, the number of axons (unmyelinated and myelinated) increased from 0.17 x 10(6) axons at E18 to 1.08 x 10(6) axons at P4 and it was almost the same at P180 (1.01 x 10(6) axons). In H rats the number of axons between P14 and P180 was similar to that of C rats. In contrast, there were only 0.11 x 10(6) myelinated axons at P180 resulting in a 66% reduction with respect to C rats (0.36 x 10(6) axons). In the CC of C rats, the number of myelinated axons increased from 1.76 x 10(3) axons at P12 to 3.34 x 10(6) axons at P184. In H rats, there were only 0.84 x 10(6) axons at P184 resulting in a 76% reduction with respect to C rats. This reduction was more important in the posterior sector of the CC (95%) than in the rest (on average 63%). Therefore these results show that thyroid hormones play an important role in the processes involved in the maturation of commissural axons.
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PMID:Role of thyroid hormones in the maturation of interhemispheric connections in rats. 784 Aug 96

Mutation of the gene encoding Caytaxin causes human Cayman ataxia by interfering with normal splicing and, in mutant rodents, by reducing normal transcription, which leads to ataxia, dystonia, and mental retardation: These observations suggest that Caytaxin may be crucial for higher brain functions such as motor learning. We generated antibodies against mouse Caytaxin. Interestingly, we found that the expression of Caytaxin is regulated during brain development while quantitative real time RT-PCR indicated that the mRNA level did not change between postnatal days 7 (P7) and P14 in the cerebellum and hippocampus, implying that the expression of Caytaxin may be controlled by a post-transcriptional mechanism. Immunostaining analyses demonstrated that Caytaxin was localized in many brain areas including the cerebellum and hippocampus. Furthermore, Caytaxin was localized to the presynaptic cytosol by the subcellular fractionation of mouse brain and an observation that was confirmed by co-localization studies with synapsin I and VGLUT1. The above data, disease phenotypes, and mutant animals suggest that Caytaxin may be essential for synaptic function. Thus, identifying the role of Caytaxin in synapse maturation may lead to the development of therapeutic interventions for cerebellar ataxia as well as mental disorders.
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PMID:Expression and localization of Cayman ataxia-related protein, Caytaxin, is regulated in a developmental- and spatial-dependent manner. 1715 73

In order to understand the alcohol's toxicity to the quantitative alternations of synapses in mouse visual cortex, the expression of synaptophysin after prenatal alcohol exposure was investigated. In present study, the experimental mice at P0, P7, P14 and P30 were grouped, as control, 2 g x kg(-1) alcohol treatment and 4 g x kg(-1) alcohol treatment. The pre-synaptic elements which were used to represent synapses were marked with synaptophysin (a synaptic vesicle associated protein) by immunocytochemistry technique. The synaptophysin positive boutons in layer VI of visual cortex were imaged under laser confocal microscope. With stereological methods, the number cal density of synapse in visual cortex was calculated in different groups at various ages. Moreover, Western blotting was carried out to detect the expression of synaptophysin in visual cortex. The results showed that prenatal alcohol exposure could cause synaptic loss with long-term effect and in a dose dependent manner. For instance, there were significant difference among the different treatment groups of P0, P14 and P30 as well (P < 0.05). Western blotting supported the results of immunofluorescent labeling. In conclusion, prenatal alcohol exposure can induce the synaptic loss dose dependently and with long-term effect. Our findings implicate that the synaptic loss with long-term effect in CNS probably contributes to the lifelong mental retardation and memorial lowliness associated with childhood FAS.
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PMID:[Stereological study on the synapse loss in visual cortex of mouse after prenatal alcohol exposure]. 2093 77