Differential responsiveness of LH and prolactin to p-tyramine in male and female rats

The effect of p-tyramine, a natural amine which is found in the rat brain in trace amounts, was evaluated for its capacity to influence LH and prolactin secretion in male and female rats under different hormonal conditions. p-Tyramine (40 mg/kg ip) was ineffective in modifying LH levels in either female or male rats which had been gonadectomized for 2 days, but if the animals were injected with 12.5 micrograms of estradiol benzoate (EB) on the day of castration, p-tyramine was able to release LH in female but not in male rats. To evaluate whether early androgenization of brain structures which control LH secretion was involved in the sexual difference observed, p-tyramine was tested in female androgenized rats (200 micrograms of testosterone propionate on the day of birth), and in male rats castrated at birth. The trace amine was ineffective in altering LH levels in both experimental models, even if rats were pretreated with EB as control females. On the other hand, p-tyramine inhibited prolactin secretion in male rats pretreated with EB, and not in similarly treated female rats. The present results suggest that p-tyramine may be involved not only in prolactin regulation as it has been previously shown, but also in LH control, and that the hormonal response to this amine is sexually differentiated in the rat.     

Variations of elemental distribution in brain regions of neonatal rats at different iodine intakes

Iodine deficiency (ID) can result in irreversible damage to the brain during the fetal and neonatal stages. As the active center of many enzymes, trace elements play essential roles in brain function. In this work, the relative contents and distributions of elements (Cl, Br, Fe, Cu, and Zn) in two important brain regions, the cerebral cortex and hippocampus, of the iodine-deficient model rats were determined by the synchrotron radiation X-ray fluorescence (SRXRF) method. Meanwhile, the ID rats were supplemented with adequate and excessive iodine, respectively. The results indicated that the distributions of trace elements could be influenced by the different iodine intakes in the stage of brain development. In contrast to the control group, the contents of Cl, Br, and Zn in two brain regions showed a significant increase in the ID group; however, both Fe and Cu decreased in the cerebral cortex and increased in the hippocmapus in the ID group. In addition, only slight changes of elemental contents in brain were found between the adequate and excessive iodine-supplemented rats.     

The effects of sex and season on the metal levels and proximate composition of red mullet (Mullus barbatus Linnaeus 1758) caught from the Middle Black Sea

The effects of seasonal and sexual differences on the levels of macro, trace element, and toxic metal levels in Mullus barbatus were investigated using the ICP-MS. The quantity relationships of macro elements were found as K>P>Na>Ca>Mg for male, P>K>Na>Ca>Mg in female; the quantity relationships of trace elements were determined as Fe>Zn>Mn>Mo>Se>Cu>Ni>Co in male, Fe>Zn>Mn>Se>Cu>Ni>Mo>Co in female; and the quantity relationship of toxic elements were found as As>Pb>Cd in both male and female. Macro, trace, and toxic metal levels showed no significant differences (p > .05) in terms of sexuality, but demonstrated seasonal differences (p > .05). Overall, the highest level of macro elements was determined in the autumn, while the high level of trace elements was measured in the winter. The As, Cd, and Pb levels in the muscle tissue of red mullet fish were higher than acceptable limits. However, when the Estimated Daily Intake (EDI) and Estimated Weekly Intake (EWI) of both toxic metals are considered, they appear to be below acceptable limits. As a result, it was determined that the red mullet had been contaminated with toxic metals (Cd and Pb) but their levels according to EDI and EWI were below the limit.     

Brain Trace Element Concentration of Rats Treated with the Plant Alkaloid, Vincamine

Trace elements are essential for normal brain functions. Tiny amounts of these elements help in the formation of neurotransmitters and involved in the antioxidant defense and intracellular redox regulation and modulation of neural cells. Vincamine is a plant alkaloid used clinically as a peripheral vasodilator that increases cerebral blood flow and oxygen and glucose utilization by neural tissue to combat the effect of aging. Neurodegenerative diseases associated with aging characterized by a disturbance in trace element levels in the brain. The objective of this study was to determine the level of zinc (Zn), copper (Cu), iron (Fe), Selenium (Se), and chromium (Cr) in the brain of rats treated with vincamine. Vincamine was injected i.m. to rats at a dose of 15 mg/Kg bodyweight daily for 14 days. Twenty-four hours after the last injection, rats were killed, and brains were ashed and digested by concentrated acids and analyzed for trace elements concentrations by flame emission atomic absorption spectrophotometer. The results showed that Zn was the highest trace element in the brain of control rats (3.134?±?0.072 ppm) and Cr was the lowest (0.386?±?0.027 ppm). Vincamine administration significantly (p?<?0.01) reduced the brain Fe concentration (1.393?±?0.165 ppm) compared to control (2.807?±?0.165 ppm). It was concluded that Zn was the highest trace element in the brain of rats. Vincamine administration resulted in approximately 50% reduction in brain Fe concentration which suggests its beneficial effect to prevent the oxidative stress of Fe in neurodegenerative diseases such as Parkinson’s, Alzheimer’s, and Huntington’s diseases.     

Transport of essential nutrients across the blood-brain barrier of individual structures

The movement of essential substrates from plasma into cerebral structures has been studied in detail in normal alert rats as well as in rats with various metabolic abnormalities. Briefly, radioactive substrates were infused i.v. to rapidly establish and maintain a trace concentration in arterial blood. The rats were killed shortly thereafter, the brain was removed and frozen, and thin sections were cut for quantitative autoradiography. The permeability-to-surface area product (PA) was calculated from the amount of radioactivity accumulated by the brain and the integral of plasma radioactivity. Influx was calculated as the product of PA times plasma substrate concentration. This approach was used to measure the influx of glucose, neutral amino acids, basic amino acids, and ketone bodies. Studies were made of normal rats, rats with portacaval shunts (a model of hepatic encephalopathy), starved rats, diabetic rats, and normal rats infused with ammonium acetate. The results demonstrate specific changes in individual transport systems, which in most cases occurred throughout the brain, although some structures were affected more than others.     

Changes in free radicals,trace elements,and neurophysiological function in rats with liver damage induced byD-galactosamine

The changes in trace elements, free radicals, and neurophysiological function were investigated in rats with liver damage induced byd-galactosamine (GalN). The elevated results showed that all the parameters related to free radical metabolism changed after administration of GalN. Relative free radical concentration, malonaldehyde (MDA), and oxidized glutathione (GSSG) elevated, but reduced glutathione (GSH) decreased. Concurrently, zinc, copper, manganese, and selenium contents in liver were significantly reduced, whereas iron was elevated. In rats with hepatic encephalopathy (HE) owing to fulminant hepatic failure (FHF) induced by a high dosage of GalN, the latencies of VEPs were delayed. Moreover, there is a correlation between Zn content of brain and the latencies of VEPs. The results of this study suggested that lipid peroxidation by free radicals might be responsible for GalN-induced liver damage in which trace elements were involved, and that change in brain Zn might play a role in the neural inhibition of HE owing to FHF.     

Ytterbium and trace element distribution in brain and organic tissues of offspring rats after prenatal and postnatal exposure to ytterbium

Lanthanides, because of their diversified physical and chemical effects, have been widely used in a number of fields. As a result, more and more lanthanides are entering the environment and eventually accumulating in the human body. Previous studies indicate that the impact of lanthanides on brain function cannot be neglected. Although neurological studies of trace elements are of paramount importance, up to now, little data are provided regarding the status of micronutritional elements in rats after prenatal and long-term exposure to lanthanide. The aim of this study is to determine the ytterbium (Yb) and trace elements distribution in brain and organic tissues of offspring rats after prenatal and long-term exposure to Yb. Wistar rats were exposed to Yb through oral administration at 0,0.1, 2, and 40 mg Yb/kg concentrations from gestation day 0 through 5 mo of age. Concentrations of Yb and other elements (Mg, Ca, Fe, Cu, Mn, and Zn) in the serum, liver, femur, and brain regions (cerebral cortex, hippocampus, cerebellum, and the rest) of offspring rats at the age of 0 d, 25 d, and 5 mo were analyzed by inductively coupled plasma-mass spectrometry. The accumulation of Yb in the brain, liver, and femur is observed; moreover, the levels of Fe, Cu, Mn, Zn, Ca, and Mg in the brain and organic tissues of offspring rats are also altered after Yb exposure. This disturbance of the homeostasis of trace elements might induce adverse effects on normal physiological functions of the brain and other organs.     

Level of neuroactive steroids in the brain, and gender-related differences in formation and decrease of conditioned reflex in rats

We investigated gender-related differences in dynamics of the brain sexual steroids during learning and the decrease of conditioned reflex in the modeling experiment. It was revealed that, before training to conditioned reflexes, females manifested a greater anxiety than males. Significant differences between males and females in formation of the conditioned reflex of passive avoidance were not revealed, whereas the conditioned response decrease were by 2-3 days faster in male rats than in females. It was revealed that there was an increase of testosterone content in various structures of the brain, especially in hippocampus and frontal cortex with its constant level in the blood plasma in learning conditioned response of passive avoidance in male adult rats. Also an increased estradiol concentration was found in females' amygdale, while increased value of estradiol was detected in hippocampus and the singular cortex in decrease of the conditioned response of passive avoidance. In blood plasma, the testosterone level was not changed, and the estradiol concentration was reduced significantly after the decreased conditioned reflex. Different dynamics of changes in the levels of sex steroids in the brain and the blood plasma can indicate a probability of their formation in nervous tissue. The correlation analysis confirms the conception about selective involvement of the brain's testosterone and estradiol in the specific structures in realization ofthe learning and memory processes in adult male and female rats.     

Central nervous system control of alcohol dehydrogenase activity in rats

The activity of alcohol dehydrogenase is higher in the livers of female rats than that in male rats. Stereotaxic lesions of the anterior periventricular hypothalamus of male rats increased the activity of alcohol dehydrogenase by about 50 percent; larger lesions which destroyed many of the major hypothalamic nuclei increased the enzyme activity 100 percent and abolished the sexual difference in alcohol dehydrogenase activity. The changes in enzyme activity were independent of changes in plasma thyroxine, testosterone and estradiol levels. Hypothalamic lesions in female rats had no effect on the enzyme activity. The sexual difference in alcohol dehydrogenase activity in rats is under hypothalamic control and does not appear to be mediated directly by the plasma level of androgens or estrogens.     

Effect of individual peculiarities on formation of preference of ethanol in female and male Wistar rats

Individual characteristics of animal behavior can serve a prognostic parameter of predisposition to use of alcohol. The goal of the work was to study dynamics of formation of preference of alcohol at early stages in the process of forced alcoholization in male and female rats as well as the accompanying changes in behavior parameters. For 3 months, the rats were submitted to the forced alcoholization with 10 % ethanol. Each week the rats were tested in the "two-glass trial". Individual peculiarities of all animals were evaluated prior to, after 6 weeks, and after the end of the experiment with aid of the "open field test" and "Suok-test". Results showed that the male rats demonstrating by the end of the experiment the significantly higher level of the alcohol preference, at the initial stages of the forced alcoholization demonstrated the significantly lower preference as compared with the remaining ones. These rats also showed the lower levels of the motor and exploratory activities before alcoholization as compared with control. On the contrary, the individuals that by the end of the experiment did not differ from control by the level of the alcohol preference demonstrated prior to alcoholization in the "Suok-test" the higher anxiety level. In female groups, no statistically significant differences were observed both in parameters of the motor and exploratory activities and in the anxiety level in both tests. Thus, in male rats, the prognostic parameter predicting formation of the abuse can serve the degree of alcohol preference at the initial stages.     

Changes in brain serotonin metabolism and [3H]-serotonin receptor binding during recall of conditioned passive avoidance in rats

The content of serotonin and its metabolite 5-hydroxyindoleacetic acid, monoamine oxidase activity, and [3H]-serotonin radioligand receptor binding were examined in the prefrontal cortex, striatum, amygdala, hippocampus and periaqueductal gray matter at different time after one-trial passive avoidance training of rats. Changes in the serotonergic activity were observed only in rats, which showed retrieval of conditioned passive avoidance response. No serotonergic changes were found immediately and one day after training. Also, there were no changes in trained rats without retrieval of conditioned passive avoidance response or rats with experimental amnesia. The pattern of the involvement of brain structures in the retrieval process was also revealed. [3H]-serotonin binding was decreased in the amygdala, periaqueductal gray matter and striatum, whereas it did not change in the prefrontal cortex and hippocampus. At the same time, the serotonin content in these structures did not differ from that of intact rats. Deamination of serotonin by monoamine oxidase and active transport of 5-hydroxyindoleacetic acid from nerve terminals were increased in the amygdala and periaqueductal gray matter, whereas in the striatum serotonin catabolism was decreased. The obtained differences in serotonin catabo- lism suggest that the decrease in receptor binding of serotonin in these brain structures is provided by different synaptic processes: presynaptic changes in the striatum and postsynaptic receptor changes in the amygdala and periaqueductal gray matter. It is concluded that the decrease in the serotonergic activity in the amygdala and periaqueductal gray matter represents one of the mechanisms activating the emotiogenic system mediating the memory trace retrieval in inhibitory avoidance learning.     

The effects of age and sex on seven elements of Sprague-Dawley rat organs

This study reports age-related changes in 7 element (iron, copper, zinc, manganese, mercury, cadmium and lead) concentrations in the liver, kidney and brain of male and female Sprague-Dawley rats from 1 to 364 days of age. Atomic absorption spectrometry was used for the measurements. Copper, mercury and cadmium in the male and female kidneys increased from weaning until 127 days of age, as did iron concentrations in the female liver and kidney. After 127 days, especially, the copper concentration in the female kidney and cadmium concentration in the male and female kidney increased further. Consistent and statistically significant (P less than 0.05) sex differences in element concentrations were found for three elements (iron, copper and zinc). Except for the zinc concentration in the liver from 50 to 72 days, iron (in liver and kidney), zinc (in kidney) and copper (in liver, kidney and brain) concentrations in female rats during the adult stage, were all higher than those of male rats. Isolated differences for other elements (manganese, mercury and cadmium) were also found. The data will be helpful when setting up long-term animal investigations of the biological effect of elements.     

急性酒精中毒合并中度创伤性脑损伤大鼠海马AQP4的表达

目的:探讨大鼠急性酒精中毒合并颅脑外伤后AQP4在海马区表达的变化.方法:健康成年雄性SD大鼠96只,随机分为4组:假手术组(N组)、急性酒精中毒组(A组)、中度创伤性脑损伤组(T组)和急性酒精中毒合并中度创伤性脑损伤(AT组).腹腔注射酒精(2.5g/kg),2h后以重物自由落体击打大鼠头部建立急性酒精中毒合并中度创伤性脑损伤(traumatic brain injury,TBI)动物模型.各组动物分别存活1、3、5、14天.免疫组化方法检测海马CA1区AQP4的表达.结果:AQP4阳性产物分布于胶质纤维和毛细血管壁,各实验组表达均高于N组.术后1天T组比AT组表达显著增高(P＜0.01),术后3天AT组比T组表达增高(P＜0.05),术后14天AT组比T组表达显著增高(P＜0.01).结论:大鼠急性酒精中毒合并颅脑外伤后晚期,海马CA1区AQP4表达增高,可能加重晚期继发性脑水肿,是急性酒精中毒合并颅脑外伤预后不良的原因之一.     

Adaptation of siblings of female rats given ethanol effect of N-acetyl-L-cysteine

Summary Ethanol administration to female rats before and during pregnancy resulted in decreased number of litters and increased activities of serum GOT, GPT and ALP. The hepatotoxicity of ethanol was indicated by the histological alterations both in the mother and siblings. There was increased levels of tissue lipids in mother and litters born to alcoholic rats. The concentration of TBARS in the liver and kidney were significantly increased in alcohol treated rats and their litters. The activities of the anti-peroxidative enzymes SOD and CAT were decreased on alcohol treatment in female rats. The glutathione content in liver and kidney decreased significantly in litters born to alcoholic rats.We have observed that the treatment with N-acetylcysteine offers protection against the toxic effect of alcohol in female rats during pregnancy and litters born to them. In N-acetylcysteine treated rats the number of litters as well as the average birth weight were close to that of control animals. Nacetylcysteine decreases the activities of serum GOT, GPT and ALP in female rats. We have also observed decreased levels of tissue lipids in mother and litters born to alcoholic rats given N-acetylcysteine when compared to alcoholic rats. The levels of TBARS in liver, kidney were also decreased both in mother and litter born to alcohol + N-acetylcysteine, while the activities of SOD and CAT were increased in liver of alcoholic rats given N-acetylcysteine when compared to alcoholic rats. Histopathological studies also showed the protective effect of N-acetylcysteine in both mother and litter in liver and kidney against alcoholic induced toxicity.     

微量元素在大鼠体内的分布

为了研究微量元素在大鼠体内的分布,本实验将大鼠分为两组,喂镍组大鼠每天灌喂1％硫酸镍0.25毫升,另一组大鼠喂水作对照,一个月后,处死全部大鼠,取鼻咽、气管、食管、胃、小肠、心、肝、脾、肺、肾、大脑、颅骨及皮毛等13种器官和组织,用发射光谱技术测定微量元素的含量。结果表明,喂镍组大鼠的鼻咽、气管、食管、肺、颅骨、心、脾和肾的镍含量显著地高于正常组(P<0.01),实验组大鼠鼻咽的镍含量明显增高这一事实,可以解释硫酸镍在诱发大鼠鼻咽癌的作用。     

Effect of monofluoromethyldopa (MFMD) on trace amine levels

The concentrations of the trace amines, m-tyramine, p-tyramine, phenylethylamine and tryptamine, were measured in the striatum of the brain and in the kidney of adult rats treated with alpha-monofluoromethyldopa (MFMD), an inhibitor of aromatic amino acid decarboxylase. While MFMD decreased the levels of all four amines in the kidney, only phenylethylamine and tryptamine levels were decreased in the striatum compared to control. Striatal p-tyramine levels were not affected, while striatal m-tyramine levels were increased by MFMD. When the rats were injected with a monoamine oxidase (MAO) inhibitor before MFMD administration, similar changes in striatal and kidney trace amine levels were observed compared to MFMD alone.     

Morphological evaluation and analysis of trace elements in the liver of rats who were fed with feed containing power station ashes

The experiment was carried out on white Wistar rats. The rats in the experimental groups received fodder containing power station ashes for various periods of time (from 6 to 18 weeks). During the experiment, the body weight of rats was recorded, the amount of trace elements in the liver was estimated, and morphological tests of the liver were carried out. The results of these experiments indicate that feeding the rats on fodder containing power station ashes causes several percent increase in the body weight and slight differences in accumulation of trace elements. Morphological changes in the liver are connected with the vacuolization of the hepatocytes' cytoplasma and an increase in the amount of phagocytic cells in hepatic sinuses. The intensity of morphological changes was correlated with the time of experiment.     

Level of neuroactive steroids in the brain and sex-related peculiarities of formation and extinction of conditioned reflex in rats

Sex-related peculiarities of dynamics of brain sex steroids in the process of learning and extinction of the conditioned reflex of passive avoidance have been studied in model experiment. Prior to learning of the conditioned reflex, female rats were found to be distinguished by manifestation of anxiety and fear as compared with male rats. At formation of the conditioned reflex, no significant sex-related differences were detected between males and females, whereas extinction of the conditioned reaction of passive avoidance in males occurred by 2–3 days faster than in females. At learning of conditioned reaction of passive avoidance, in sexually mature male rats there was revealed an increase of the testosterone content in various brain structures, especially in hippocampus and frontal cortex, while its level in blood plasma remained unchanged. Also shown was an elevation of estradiol concentration in female amygdale, whereas at extinction of the conditioned reaction of passive avoidance, a rise of estradiol values was noted in hippocampus and cingular cortex. At the same time, the testosterone level in blood plasma did not change, whereas after extinction of the conditioned reflex the estradiol concentration decreased statistically significantly. Different dynamics of changes of the sex steroid levels in brain and blood plasma can indicate a possibility of their formation in the nervous tissue. The performed correlation analysis confirms the concept of selective involvement of testosterone and estradiol of individual brain structures in realization of processes of learning and memory in sexually mature male and female rats.     

Morphological studies of the rat liver after experimental administration of carbon ashes and coal dust

The experiments were carried out in Wistar rats which were given intratracheally samples of carbon ashes or soil dust in the form of the respirable fraction. The morphologic changes and the glycogen content in the experimental animals' livers were evaluated. The content of the trace elements was determined in the applied carbon ashes and soil dust by means of the X-rays diffraction method. The results of the studies show that the morphologic changes in liver depend on the kind of dust and are related to the content of the trace elements and the free silicon dioxide in the carbon ashes and the soil dust.