Immunoreactive-β-endorphin and LHRH levels in the brains of aged male rats with impaired sex behavior

—Levels of immunoreactive β-endorphin and luteinizing hormone releasing hormone (LHRH) were measured in brain tissue of aged male Long-Evans rats. The animals were tested for sex behavior twice in one week at bimonthly intervals between the 7th and 27th month of life and were sacrificed along with a group of young (5-month old) sexually active rats. Thirty-one of the 89 rats which began the study remained healthy and tumor-free. By month 27, 21 of these had completely ceased to mate and 10 continued to show adequate sexual behavior. Diminished levels of β-endorphin-like immunoreactivity were measured in the hypothalami and hindbrain of the old animals grouped together as compared to young animals and this reduction was shown to be significantly greater in hypothalamic tissue from the behaviorally inactive subgroup. Hypothalamic LHRH levels were not significantly altered by age in these animals. However, a marked reduction of LHRH content in the septal and midbrain regions of the aged-behaviorally inactive subgroup was evident when compared with the behaviorally active group. The data suggest that altered function of β-endorphin and LHRH neurons of the aged brain may be involved in the behavioral deterioration observed in aged animals.     

Age-related changes in brain proDynorphin gene expression in the rat

Dynorphin has a well-established role in feeding and gustation. Alterations in taste perception and feeding behavior are common with age. We hypothesized that proDynorphin gene expression in brain areas involved in taste and feeding declines with age. Male Sprague-Dawley rats were housed individually with ad libitum access to food and water. Brain punches of the selected regions were dissected out in groups of rats aged 4–6, 12–14 and 18–21 months. ProDynorphin mRNA (measured using a cDNA probe) decreased significantly with age in arcuate nucleus and amygdala; increased significantly with age in hippocampus; and was not significantly affected in nucleus of the solitary tract, cortex, caudate putamen or hypothalamic paraventricular nucleus. These data suggest an age-related decrease in the synthesis of dynorphin in two brain regions strongly associated with feeding behavior, and an increase in dynorphin synthesis in a brain region associated with learning and memory.     

Alterations in the activity and expression of endothelial NO synthase in aged human endothelial cells

This study was to investigate factors underlying the age-related decrease in NO production in vascular endothelial cells. The age-related changes in NO production, the activity and expression level of eNOS, and eNOS binding proteins, were studied in HUVECs.NO production in HUVECs significantly decreased in an age-dependent manner. The potentiation of NO production by l-Arg was significantly suppressed by L-NIO (eNOS-specific inhibitor) in young HUVECs and was suppressed by 1400W (iNOS-specific inhibitor) in aged HUVECs. The aged HUVECs had lower eNOS protein levels than young cells. eNOS phosphorylation at Ser-1177 (active) decreased gradually from PDL 23 through 40, and eNOS phosphorylation at Thr-495 (inactive) increased in aged cells. Changes of intracellular eNOS binding proteins, such as caveolin-1, pAkt, and Hsp90, as well as interaction between eNOS and eNOS binding proteins, indicated decreasing enzyme activity in aged HUVECs.Aging might decrease the activity as well as expression level of eNOS in HUVECs. And the decrease in eNOS activity probably implicated to the alterations in the regulatory binding proteins. For further study, it needs to be confirmed that the age-related change in the intracellular distribution of eNOS and the relative contribution of eNOS and iNOS on vascular dysfunction in aged endothelial cells.     

Tissue-specific functions based on information content of gene ontology using cap analysis gene expression

Gene expressions differ depending on tissue types and developmental stages. Analyzing how each gene is expressed is thus important. One way of analyzing gene expression patterns is to identify tissue-specific functions. This is useful for understanding how vital activities are performed. DNA microarray has been widely used to observe gene expressions exhaustively. However, comparing the expression value of a gene to that of other genes is impossible, as the gene expression value of a condition is measured as a proportion of that for the same gene under a control condition. We therefore could not determine whether one gene is more expressed than other genes. Cap analysis gene expression (CAGE) allows high-throughput analysis of gene expressions by counting the number of cDNAs of expressed genes. CAGE enables comparison of the expression value of the gene to that of other genes in the same tissue. In this study, we propose a method for exploring tissue-specific functions using data from CAGE. To identify tissue-specificity, one of the simplest ways is to assume that the function of the most expressed gene is regarded as the most tissue-specific. However, the most expressed gene in a tissue might highly express in all tissues, as seen with housekeeping genes. Functions of such genes cannot be tissue-specific. To remove these from consideration, we propose measuring tissue specificity of functions based on information content of gene ontology terms. We applied our method to data from 16 human tissues and 22 mouse tissues. The results from liver and prostate gland indicated that well-known functions of these tissues, such as functions related to signaling and muscle in prostate gland and immune function in liver, displayed high rank.     

Parallel changes in gene expression in aged human and mouse cortex

The intensity of expression of over 20,000 genes and expressed sequence tags within the cerebral cortex has previously been described for both the human and mouse genomes. In both these species, the degree of expression of a relatively limited number of cortical genes, around 300, is significantly altered during senescence. The extent of similarity between age-related alterations of levels of specific mRNAs in either species has been compared. There is a significant correlation between species in those genes whose expression changes markedly in either direction with aging. This parallel serves to validate the use of mouse strains to study general age-related genetic events associated with aging.     

Lifetime brain serotonin: Regional effects of age and precursor availability

In the rat, regional brain serotonin levels which do not change from 2–30 months of age are increased at 36 months. Corresponding catecholamine levels progressively decrease. Feeding a diet restricted in the amino acid tryptophan (the precursor of serotonin) from weaning to two years of age markedly reduces serotonin levels in all brain regions and lowers norepinephrine levels in the cerebral hemispheres. Regional activity of synthesizing (tyrosine and tryptophan hydroxylases) and catabolizing enzymes (MAO-A) does not change markedly with age or dietary manipulation except for sporatic increases in tryosine hydroxylase activity in pair-fed animals. Returning the tryptophan-deficient animals to a normal diet produces a certain degree of rehabilitation the effectiveness of which varies with the function considered: Impaired brain serotonin levels recover moderately but remain lower than controls as late as 36 months, growth is never completely compensated, and norepinephrine levels show a rebound increase.     

The effect of hypoxia on monoamine levels in discrete regions of aged rat brain

Aged rats were exposed to 10% oxygen for 2, 13, and 36 hr. Norepinephrine levels in cerebral cortex, hypothalamus, hippocampus, midbrain, cerebellum, ponsmedulla and dopamine levels in striatum were determined after each exposure. While there was no significant change in monoamine levels in brain regions after 2 hr, norepinephrine concentration in hypothalamus and midbrain decreased significantly after 13 hr of hypoxia. After 36 hr in a hypoxic environment, levels of the monoamines in brain regions were similar to the controls. This would suggest NE metabolism is most vulnerable to hypoxia in two regions of the aged brain. The precise mechanism of these changes is unknown, but they suggest both a vulnerability and an adaptive recovery of central adrenergic metabolism by the aged brain under hypoxia.     

老年大鼠空间记忆减退与cNOS基因表达变化

目的：从基因表达角度研究原生型NOS（cNOS,包括神经元型nNOS和内应型eNOS）与老年记忆减退发生的关系。方法：用Morris水迷宫将老年大鼠筛选为记忆正常和记忆减退两组,以老年记忆减退大鼠作为老年记忆减退模型;用半定量反转录一聚合酶链反应（RT－PCR）方法测定nNOS和eNOS的mRNA含量。结果：（1）海马组织中老年记忆正常组和老年记忆减退组较青年组nNOS和eNOSmRNA含量均下降,nNOS以记忆减退组下降更为显著;（2）小脑组织中老年记忆减退组nNOS和eNOSmRNA含量的下降与老年记忆正常组和青年组均有显著差异。（3）额叶组织nNOSmRNA含量三组之间均无显著差异;eNOSmRNA含量老年记忆正常组和老年记忆减退组技青年组均下降,以记忆减退组下降更为显著。结论：老年记忆减退的发生可能与有关脑区cNOS基因表达下降有关。     

Regional and cellular gene expression changes in human Huntington's disease brain

Huntington's disease (HD) pathology is well understood at a histological level but a comprehensive molecular analysis of the effect of the disease in the human brain has not previously been available. To elucidate the molecular phenotype of HD on a genome-wide scale, we compared mRNA profiles from 44 human HD brains with those from 36 unaffected controls using microarray analysis. Four brain regions were analyzed: caudate nucleus, cerebellum, prefrontal association cortex [Brodmann's area 9 (BA9)] and motor cortex [Brodmann's area 4 (BA4)]. The greatest number and magnitude of differentially expressed mRNAs were detected in the caudate nucleus, followed by motor cortex, then cerebellum. Thus, the molecular phenotype of HD generally parallels established neuropathology. Surprisingly, no mRNA changes were detected in prefrontal association cortex, thereby revealing subtleties of pathology not previously disclosed by histological methods. To establish that the observed changes were not simply the result of cell loss, we examined mRNA levels in laser-capture microdissected neurons from Grade 1 HD caudate compared to control. These analyses confirmed changes in expression seen in tissue homogenates; we thus conclude that mRNA changes are not attributable to cell loss alone. These data from bona fide HD brains comprise an important reference for hypotheses related to HD and other neurodegenerative diseases.     

慢性缺氧和二氧化碳潴留大鼠脑阴离子转运蛋白的研究

目的：观测慢性缺氧和二氧化碳潴留大鼠脑桥组织中脑阴离子转运蛋白（ＡＥ３）ｍＲＮＡ的变化。方法：采用密闭舱内灌注混合气体的方法，分别复制慢性缺氧，慢性缺氧伴二氧化碳潴留及慢性呼吸性酸中毒大鼠模型，以地高辛标记的（ＡＥ３）ｃＤＮＡ探针，应用点杂交技术，对各实验组及对照组大鼠脑桥组织中ＡＥ３ｍＲＮＡ的相对含量进行测定。结果：（１）慢性缺氧组ＡＥ３ｍＲＮＡ的相对含量明显地低于对照组（Ｐ〈０．０５），慢性缺     

Regional decline of cerebral blood flow with age in cognitively intact subjects

Cerebral blood flow was measured by the 133Xenon washout method in 44 cognitively intact subjects. Regression analysis of cerebral blood flow with age was performed on data from 33 subjects without arteriosclerotic cardiovascular disease, hypertension, or chronic obstructive pulmonary disease, factors which have been previously shown to lower cerebral blood flow. Changes with normal aging were significant in the left and right hemispheres with bilateral changes in temporal, parietal, and occipital regions. An additional group of 11 cognitively intact subjects with arteriosclerotic cardiovascular disease but no accompanying dementing disease had lower mean flow values at each detector position than did age- and sex-matched controls, although the differences did not always reach statistical significance. Decreased flows in temporal regions seem to be a concomitant of normal aging, and are not related to the presence of vascular disease.     

Rheological properties of young and aged human erythrocytes

Summary Rheological properties were studied of young and old human erythrocytes from healthy adults. Viscosity measurements of packed erythrocyte suspensions as well as filtration of cells through polycarbonate sieves show that young cells are more flexible than aged ones. Since deformability of erythrocytes is the product of cell shape, flexibility of the membrane and fluidity of the intracellular hemoglobin, we studied the manner in which these factors are relevant to the diminished flexibility of aged erythrocytes. The biconcave cell shape is maintained during the process of aging. The viscosity of packed ghost suspensions from aged erythrocytes is increased versus that of young ones. The diminished flexibility of old ghosts correlates well with their smaller cell volume. The fluidity of the hemoglobin in the interior of the cells is decreased as indicated by an increased hemoglobin content of the isolated ghosts. We conclude that aged erythrocytes loose their deformability as a result of both a decreased fluidity of the intracellular hemoglobin and a diminished flexibility of the membrane.This work was supported by the Deutsche Forschungsgemeinschaft     

Metallothionein-I-II expression in young and adult bovine pineal gland

Aging is characterized, among other features, by an increased concentration of metal ions in the brain that may contribute to a greater increase in free radicals production. The present paper reports data regarding the concentration of some relevant metal ions (Cu, Fe, Mn, Zn), as well as the immunopositivity of metallothionein-I-II and GFAP in the bovine pineal gland with respect to animal aging. The pineal gland of young bovines displays several immunoreactive metallothionein-I-II positive elements in the parenchyma, whose number decreases with age. We also report that a well defined group of neurons bordering the third ventricle and located close to the subcommissural organ shows an intense metallothionein-I-II immunopositivity. The presence of metallothionein-I-II was confirmed by means of liquid chromatography coupled to tandem mass spectrometry. In particular, it proved possible to identify the amino acid sequences of the unique tryptic peptide not containing cysteine and two pepsin fragments containing cysteines. In conclusion, our data suggest the presence of a metallothionein-I-II expressing system in the pineal gland and ventricle-adjacent areas of the bovine epithalamus might possibly be related to the anti-aging effects of melatonin.