18月龄雌性大鼠下丘脑内源性阿片肽含量及其mRNA水平变化的…

本文应用分子生物学和放射免疫测定方法，观察了老年前期雌性大鼠下丘脑、垂体和血浆中内阿片肽含量及下丘脑内阿片肽基因表达的变化。与５月龄青年大鼠比较，１８月龄雌性大鼠下丘脑和血浆β－ＥＰ、Ｌ－ＥＮＫ、Ｄｙ－ｎＡ含量减少，垂体β－ＥＰ、Ｌ－ＥＮＫ含量升高，ＤｙｎＡ含量降低（Ｐ〈０．０５￣０．０１）。下丘脑ＰＯＭＣ基因和ｐｒｏｅｎｋｅｐｈａｌｉｎ基因ｍＲＮＡ水平明显低于青年大鼠（Ｐ〈０．０５）。结果提示，     

寒冷条件下大鼠血浆,垂体,下丘脑中β—EP含量的改变

本文利用健康成年雄性Ｗｉｓｔａｒ大鼠，采用放射免疫学方法，观测了大鼠在不同寒冷条件下血浆，垂体，下丘脑中β－ＥＰ含量变化。结果表明：血浆，垂体，下丘脑中β－ＥＰ含量在冷刺激过程中总的趋势表现为升高，但Ⅱ组垂体中β－ＥＰ含量下降（Ｐ＜０．０５），且下丘脑中β－ＥＰ含量明显升高（Ｐ＜０．００１）。     

寒冷条件下大鼠血浆、垂体、下丘脑中β－EP含量的改变

本文利用健康成年雄性Ｗｉｓｔａｒ大鼠，采用放射免疫学方法，观测了大鼠在不同寒冷条件下血浆、垂体、下丘脑中β－ＥＰ含量变化。结果表明：血浆、垂体、下丘脑中β－ＥＰ含量在冷刺激过程中总的趋势表现为升高，但Ⅱ组垂体中β－ＥＰ含量下降（Ｐ＜０．０５），且下丘脑中β－ＥＰ含量明显升高（Ｐ＜０．００１）。     

氯化镧对大鼠生长素分泌调节影响的体外研究

目的：研究氯化湖（LaCl3）对大鼠生长素分泌调节轴的影响。方法：采用荧光法检测离体脑片培育液中单胺类神经递质含量;用放射免疫法测垂体脑片育液中生长素（GH）含量。结果：①0．01mmol／LLaCl3垂体组育液中GH含量明显高于对照组（P＜0．05）;而1mmol／LLaCl3垂体组有液中GH含量明显低于对照组（P＜0．05）。②0.01mmol／LLaCl3下丘脑＋垂体组,其有液中GH含量则明显高于对照组（P＜0．01）和同剂量的单纯垂体组（P＜0．01）;但1mmol／L下丘脑＋垂体组育液中GH含量与对照组比较无显著差异（P＞0．05）。③0．01mmol／LLaCl3下丘脑组有液中NE含量明显高于对照组（P＜0．01）,5－HT明显低于对照组（P＜0.05）。④1mmol／L下丘脑组有液中NE和DA含量明显少于对照组（P＜0．01和0．05）,而5－HT含量则明显高于对照组（P＜0．001）。结论：低剂量氯化调可通过下丘脑和腺垂体双重作用促进GH分泌。     

大鼠下丘脑内前阿黑皮素原mRNA的老年变化

研究大鼠下丘脑内前阿黑皮素原（POMC）mRNA表达的老年变化，本实验采用SPraque－Dawley大鼠3月龄（青年组）和28～30月龄（老年组）各8只，利用地高辛标记POMC反义RNA探针进行原位杂交组织化学并行图象定量分析。结果：在青年组大鼠肉，OPMCmRNA阳性胞体主要分布于弓状核及其邻近区域；老年大鼠POMCmRNA胞体主要分布于弓状核的内侧，着色浅谈．与年轻大鼠相比，老年大鼠下丘脑内POMCmRNA神经元数量显著减少，（P＜0．01），胞体灰度值明显升高（P＜0．05），而胞体截面积略有增大，但差异无显著性（P＞0．05）。结果表明，大鼠下丘脑内POMCInRNA神经元有明显的老年变化，提示老年大鼠下丘脑POMC神经元胞体发生了衰老形态学改变，功能活动低下，细胞丢失，POMC的表达显著增加，生物合成功能紊乱。     

吗啡依赖大鼠镇痛及生殖功能的改变

目的　研究吗啡依赖大鼠镇痛及生殖功能的改变。方法　采用大鼠戒断模型,观察吗啡依赖大鼠下丘脑和血浆β- 内啡肽、结状神经节和孤束核P物质以及血清内分泌激素的变化。结果　吗啡依赖大鼠下丘脑β-EP的含量均正常大鼠水平降低;吗啡依赖大鼠结状神经节和孤束核 SP的含量升高;吗啡依赖雌性大鼠血清FSH、E2、PRL均低于正常对照组;吗啡依赖大鼠睾丸酮(T)含量显著降低(P<0.01)。结论　吗啡依赖大鼠下丘脑—垂体—肾上腺可能发生变化。     

亮氨酸脑啡肽与TRH-TSH-甲状腺轴互相影响的研究

目的：探索阿片类物质与TRH－TSH－甲状腺轴之间的关系的相互影响。方法：制造大鼠高甲状腺激素水平及低甲状腺激素水平动物模型,用放免法测定甲状腺激素（T3、T4、TRH、TSH）、鸦片类物质亮氨酸脑啡肽（L－EK）及用高压液相－电化学法测定神经递质5－羟色胺（5－HT）。结果：高甲组T3、T4呈逐渐升高（P＜0．01）;血清TRH迅速下降以后又回升;下丘脑TRH呈持续抑制状态,TSH显著降低（P＜0．001）,L－EK升高（P＜0．05）,5－HT降低（P＜0．05）。低甲组T3、T4显著降低（P＜0．001）,血清TSH、TRH含量逐渐升高（P＜0．001）,垂体TSH、下丘脑TRH含量逐渐降低（P＜0．01）,以后又回升;L－EK升高,5－HT降低（P＜0．01）。结论：甲状腺功能改变后TRH、TSH升高而降低,并不伴随脑纹状体中L－EK必然的同步升高而降低。     

大鼠侧脑室内注射β淀粉样蛋白(25～35)致氧化应激反应的动态变化

观察外源性β淀粉样蛋白（β－Amyloid peptide,Aβ)25-35引起大鼠大脑的氧化应激。于大鼠侧脑室内一次性注射聚集态的Aβ（25－35）15nmol后，5，9和14d分别测定海马的脂质过氧化产物丙二醛（malodialdehyde,MDA)含量的还原型谷胱甘肽（reduced glutathione,GSH)水平以及谷胱革肽过氧化物酶（glutathione peroxidase,GSH-PX)和超氧化物歧化酶（Superoxide dismutase,SOD)活性。与对照组相比，Aβ组大鼠术后5d时MDA含量增加（P＜0．05），抗氧化酶GSH－PX活性下降（P＜0．001），9d时GSH－PX和SOD活性显著升高（P＜0．01和P＜0．05）。14d时，两组间各个指标均无明显差别。结果表明在大鼠脑室内一次性注射Aβ（25－35）可导致氧化应激反应，这一改变与时间相关，可被机体抗氧化系统所代偿。     

补肾药延缓老年大鼠下丘脑—垂体—甲状腺轴的功能退化

用放射免疫分析和高效液相测定不同组织和血液的激素和神经递质含量，以观察补肾益精主药－－固真方对老年大鼠下丘脑－垂体－甲状腺轴作用的影响。结果表明：（１）与青年对照组比较，老年大鼠下丘脑Ｔ３Ｒ、ＴＲＨ明显降低，垂体ＴＳＨ呈低下趋势；（２）老年大鼠血清Ｔ２、Ｔ４含量明显下降，而ｒＴ３则显著增高；血清ＴＲＨ和ＴＳＨ呈代偿性增高；而血冰亮氨酸脑啡肽（Ｌ－ＥＫ）含量明显降低：（３）老年大鼠在脑皮层去甲肾上腺     

雌激素及其拮抗剂对大鼠脂代谢和血管活性肽水平的影响

以假手术大鼠（Sham）作为对照组,切除大鼠双侧卵巢（OVX）后,血浆17β-雌二醇（17β-E2）水平下降48％。体重增加17％（P＜0．001）,血清总胆固醇（TC）含量升高约50％（P＜0．001）,甘油三酯（TG）含量降低30％（P＜0．01）。OVX后进行雌激素替代疗法（ERT）各组（ERT1-3）的TC和TG的含量分别下降（P＞0．05）到和升高（P＜0．01）至高于对照组的水平。给于雌激素受体拮抗剂──它莫西芬（TAM）的各组（TAM,OVX＋TAM,ERT3＋TAM）中,血清TC和TG含量均低于对照组（P＜0．01～P＜0．001）。此外,OVX组血浆降钙素基因相关肽（CGRP）和内皮素水平也分别降低为对照组的69％和89％（P＜0．05）。提示卵巢激素主要是雌激素通过其受体介导参与大鼠脂代谢和体重的调节,ERT和TAM对OVX大鼠血清TC浓度及体重的调节产生有利影响。OVX大鼠血浆CGRP和内皮素水平的调节可能与雌激素水平变化有关。     

Immunoreactive β-endorphin in the plasma, pituitary and hypothalamus of young and old male rats

Immunoreactive beta-endorphin (IR-β-ENDO) was measured in the plasma, pituitary, and hypothalamus of young (3–5 mo.) and old (19–23 mo.) male Sprague-Dawley rats, using a specific radioimmunoassay. Plasma IR-β-ENDO in old male rats (3.44±10.54 ng/ml) was more than three times higher than values observed in young male rats (1.00±0.10 ng/ml). Pituitary content and concentration of IR-β-ENDO also were significantly greater in the old (5.85±0.51 μg/gland and 1.17±0.10 μg/mg protein) than in the young (3.53±0.29 μg/gland and 0.78±0.06 μg/mg protein) male rats. The content of IR-β-ENDO in the hypothalamus of old and young rats was nearly the same (43.45±2.47 and 49.88±6.35 ng/hypothalamus, respectively), whereas the concentration of IR-β-ENDO in the hypothalamus of the old male rats (3.89±0.25 ng/mg protein) was approximately 50% lower than that observed in the young male rats (7.80±0.85 ng/mg protein). These changes in plasma, pituitary, and hypothalamic IR-β-ENDO may contribute to the increase in prolactin and decrease in gonadotropins observed in old male rats, since β-ENDO administration is known to produce these effects on prolactin and gonadotropin secretion.     

Growth hormone increases the total number of cardiac myocyte nuclei in young rats but not in old rats

Previously we have shown that growth hormone (GH) increases the total number of myocyte nuclei of the left ventricle in adult rats (8 months old). In the present study, we investigated whether GH could increase the total number of myocyte nuclei of the left ventricle in young and old rats. Female rats, 3 months old and 20 months old, were injected with GH or vehicle for 80 days. Using immersion-fixed left ventricles, unbiased stereological methods were applied. The weight of the left ventricle was increased by 49% (P<0.001) in the GH-injected young rats and by 32% (P<0.01) in the GH-injected old rats compared with the controls. Compared with the control groups, there was a 31% increase in the total number of myocyte nuclei in the GH-injected young group (P<0.05), but no significant increase in the GH-injected old group. The total number of non-myocyte nuclei was increased by 59% in the young GH-injected group (P<0.001) and by 25% in the old GH-injected group (P<0.01). In conclusion, GH induced a substantial left ventricle growth in both young and old rats. GH increased the total number of myocyte nuclei in the left ventricle of young rats, but not in old rats. This study shows that the myocyte response to GH declines with ageing.     

Changes in somatotropin and thyrotropin secretory patterns in aging rats

In order to clarify whether pituitary enlargement influences the secretory patterns of growth hormone (GH) and thyrotropin (TSH) in old rats, we studied the correlation between pituitary weight and plasma levels of GH and TSH in Sprague-Dawley rats of different age and sex. Young female (3–4 months; YF), old female (25 months; OF), and senescent female (33–35 months; SF) rats and young male (3–4 months; YM) and old male (24–26 months; OM) rats carrying chronic intraatrial cannulas were used. Sequential blood samples were removed through the cannulas while the animals remained conscious and undisturbed. Plasma TSH and GH as well as serum thyroxine (T₄) and triiodothyronine (T₃) were measured by radioimmunoassay. At two years of age, both males and females showed a consistent decline in GH pulse amplitude without change in trough levels. By 33–35 months of age, females showed a reversal in the previous pattern of change for GH secretion: pulse amplitude, trough levels, and mean plasma GH increased significantly with respect to the old females. The correlation between mean plasma GH and anterior pituitary (AP) weight was positive and significant (p<0.01) for females but nonsignificant for males. Old and senescent rats showed significantly lower serum T₄, but not T₃, than young animals while plasma TSH increased with age in both sexes. The present results show for the first time that senescent females hypersecrete GH and suggest that the age-related alteration of TSH secretion in rats may be due to the low levels of T₄ present in the aged animals. The correlation analysis shows that pituitary enlargement is in general associated with increased secretion of both GH and TSH in senescent female rats.     

Effect of monoamine nervous transmitter and neuropeptide Yin the aged rats with myocardial injury after brain ischemia-reperfusion

Effect of monoamine nervous transmitter and neuropeptide Yin the aged rats with myocardial injury after brain ischemia-reperfusion     

冷水游泳对去肾上腺大鼠下丘脑,垂体和血浆AVP含量的影响

ＡＶＰ主要合成于下丘脑的室旁核和视上核，正常情况下，每毫升血浆ＡＶＰ含量在１０ｐｇ以下，近年来的研究表明，疼痛、手术、应激等强刺激可引起ＡＶＰ大量释放，血浆中的ＡＶＰ含量可达１００ｐｇ以上。由于ＡＶＰ可使血管平滑肌收缩，并具ＣＲＦ样作用，可促进垂体释放ＡＣＴＨ，因此被认为是一种应激激素，而下丘脑－垂体－肾上腺皮质轴被认为是经典的应激系统。本工作旨在通过去除应激轴上的肾上腺这一环节，来验证ＡＶＰ是否     

Immunoreactive β-endorphin in the plasma, pituitary and hypothalamus of young and old male rats

Immunoreactive beta-endorphin (IR-β-ENDO) was measured in the plasma, pituitary, and hypothalamus of young (3–5 mo.) and old (19–23 mo.) male Sprague-Dawley rats, using a specific radioimmunoassay. Plasma IR-β-ENDO in old male rats (3.44±10.54 ng/ml) was more than three times higher than values observed in young male rats (1.00±0.10 ng/ml). Pituitary content and concentration of IR-β-ENDO also were significantly greater in the old (5.85±0.51 μg/gland and 1.17±0.10 μg/mg protein) than in the young (3.53±0.29 μg/gland and 0.78±0.06 μg/mg protein) male rats. The content of IR-β-ENDO in the hypothalamus of old and young rats was nearly the same (43.45±2.47 and 49.88±6.35 ng/hypothalamus, respectively), whereas the concentration of IR-β-ENDO in the hypothalamus of the old male rats (3.89±0.25 ng/mg protein) was approximately 50% lower than that observed in the young male rats (7.80±0.85 ng/mg protein). These changes in plasma, pituitary, and hypothalamic IR-β-ENDO may contribute to the increase in prolactin and decrease in gonadotropins observed in old male rats, since β-ENDO administration is known to produce these effects on prolactin and gonadotropin secretion.     

短期饥饿对老年、成年大鼠下丘脑加压素神经元及血浆皮质酮的影响

免疫组化光、电镜法观察禁食五天老年及成年大鼠下丘脑精氨酸加压素(AVP)神经元,并检测其血浆皮质酮(B),与同龄正常鼠相比.结果:(1)B均值明显升高(P<0.01),(2)各神经核团的阳性神经元有增有减,非同步变化,(3)正中隆起外带阳性纤维密集,面积增加,(4)视上核主部及室旁核的神经元粗面内质网层次增多,线粒体较密集,(5)成年饥饿鼠阳性细胞总数增加,但其视上核主部的减少,并和血浆B的增加负相关(r=-0.98,P<0.01),而老年饥饿鼠阳性细胞总数减少,且和血浆B的相关性不明显.实验结果表明:血浆B和下丘脑AVP神经元均有明显应激反应,不论成年或老年鼠对短期饥饿均呈现合成及分泌AVP较旺盛的结构变化,但老年的饥饿应激反应弱于成年鼠的.     

The influence of forepaw palmar sensorimotor deprivation on learning and memory in young rats

This study examined the effects of early palmar forepaw sensorimotor deprivation on learning and memory in rats. Sensorimotor deprivation was performed on 18-day-old male rats. Controls were sham operated. Studies were performed on rats aged 18, 25, 35, 45 and 60 days. Morris water maze testing was used to assess learning and memory. Long-term potentiation (LTP) was assessed by electrophysiological means in slices obtained from the hippocampal Schaffer collateral pathway. Nissl staining was performed to assess pyramidal cell number in hippocampal CA1 and CA3 regions. Hippocampal N-methyl-d-aspartate receptor 1 (NMDAR1) mRNA and protein levels were assessed. Learning and short-term memory were significantly depressed in 25 and 35 day old sensorimotor deprived rats (P<0.01). LTP was also significantly depressed in sensorimotor deprived rats at these ages, while hippocampal CA1 pyramidal cell counts were significantly decreased (P<0.05). CA3 cell numbers were significantly lower in 25-day-old sensorimotor deprived rats (P<0.05). Both NMDAR1 mRNA and protein levels were significantly lower in sensorimotor deprived rats aged 25 and 35 days (P<0.05). These findings indicate that palmar surface forepaw sensorimotor deprivation impairs subsequent learning and memory in young rats. Decreased hippocampal pyramidal cell numbers and altered NMDAR1 expression may underlie this impairment.