Effect of antihypoxic agents on the cyclic nucleotide content in different brain structures in normo-oxia and hypoxia

A study was made of the effects of isothiobarbamine and guthimine (10 and 50 mg/kg, respectively) on the content of cAMP and cGMP in the brain cortex (BC) and hippocamp under normal conditions and hypoxia. Isothiobarbamine did not change the content of both cyclic nucleotides under normoxia, whereas under hypoxia it reduced the level of the cyclic nucleotides in the BC and raised it in the hippocamp. Guthimine increased their content in the BC and did not change it in the hippocamp under normoxia, whereas under hypoxia it increased the cAMP content in the hippocamp and did not change it in the BC. The cGMP content descended in both the structures under study.     

Catecholamine content of the rat brain at different stages of experimental alcoholism

Changes in the noradrenaline (NA) content in the hypothalamus, dopamine (DA) and homovanillic acid (HVA) in the striatum were determined in rats after chronic alcohol administration. A single injection of alcohol (2.5 g/kg i.p.) provoked a 30% decrease in NA only in rats predisposed to ethanol intake. Voluntary intake of 15% ethanol for 10 days made the NA content return to normal, the 4-month use of ethanol did not change whereas the 8-month use reduced the NA content by 17%, DA by 31% and raised the content of HVA by 25%. Twenty-four hours after alcohol abstinence the HVA content dropped by 13%. It is concluded that the noradrenergic system is involved in the formation and development of alcohol motivation and that the dopaminergic system participates in the development of the physical dependence and abstinence.     

The cyclic nucleotide content of the blood plasma in mice irradiated at different doses]

Cyclic nucleotide content of plasma was shown to increase after irradiation of mice within a wide range of doses. Compared was the dynamics of changes in the cyclic nucleotide content 24 hr following irradiation with supralethal doses.     

Effect of adenosine on cyclic nucleotide levels in brain structures

Adenosine influence on cAMP and cGMP levels in cortex, hypothalamus, hippocampus and cerebellum was studied. It was established that adenosine and inhibitor of its reuptake--dipyridamole change cyclic nucleotide levels in some structures of brain (intraperitoneal injection). It was shown that cAMP and cGMP were in reciprocal relations in cortex, but not in hypothalamus, hippocampus and cerebellum.     

Enkephalin content in sections of the brain of rats undergoing intrauterine exposures to ethanol

Leu- and met-enkephalin concentration in the brain structures of rat offsprings prenatally exposed to ethanol (4-5 g/kg) was investigated by radioimmunoassay. Regional and sex differences in enkephalin levels of the investigated brain structures have been shown. In experimental animals that had been exposed to ethanol leu- and met-enkephalin concentration in the hemispheric cortex and hippocump was similar to that in the controls, while in the pituitary body it was significantly decreased. The mechanisms of ethanol effect on endogenous opioid system in the developing brain are discussed.     

Effect of ionizing radiation at high doses on the cyclic nucleotide content of the rat brain

The study of the rat brain after irradiation with superlethal doses of 100 and 500 Gy has revealed a decrease in the cAMP content at early times after exposure. The most considerable decline in the cGMP content was noted in the cerebellum and cerebral hemisphere cortex where low cGMP level was retained for 24 h following irradiation. It is suggested that the observed changes play an important role in the development of the CNS syndrome.     

Effect of reserpine on the calcium content of rat aorta at different stages of development.

The preadministration of reserpine (2.5 mg/kg b.w. per os) 24 hours before the experiment did not statistically significantly affect the calcium content of the aorta of 21- and 42-day-old rats. In 90-day-old and older rats it produced a statistically significant decrease in the calcium content of the thoracic segment of the aorta, however.     

大鼠胰腺发育不同阶段基因表达分析

目的:探讨大鼠胰腺发育不同阶段基因表达规律.方法:运用高通量基因芯片技术检测大鼠胰腺从胚胎12.5天(E12.5)到成年不同时期基因表达情况.结果:基因芯片所涵盖的基因59%在E12.5有表达,65%在15.5有表达,63%在E18.8有表达,53%在新生胰腺中有表达,38%在成年胰腺中有表达.E18.5相对于E15.5表达上调的基因中代谢相关的酶类有121条,占上调基因的18.2%,E18.5相对于E15.5表达下调的基因主要是一些转录因子和骨架蛋白.结论:在大鼠胰腺的发育过程中,早中期以细胞分化为主,而后期则是以细胞功能成熟为主.     

Anti-arrhythmic action of adenosine and the cyclic nucleotide content of the myocardium of rats with ischemia

In anesthetized rats a 30-min intravenous infusion of adenosine (2.5 mg/kg/min) performed after the coronary artery ligation significantly decreased the incidence and severity of early ischemic arrhythmias. After the infusion of adenosine, there was an increase in cGMP level in the left ventricular myocardium, cAMP content remained unchanged.     

Changes in the non-structural carbohydrate content of cotton (Gossypium spp.) fibres at different stages of development

The neutral sugars (glucose, fructose, and sucrose) and the sugar phosphates (glucose 6-phosphate, glucose 1-phosphate and fructose 6-phosphate) soluble in hot aqueous 80% methanol from the fibres of cotton — Gossypium arboreum L., G. barbadense L., and G. hirsutum L. — were determined at various stages of fibre development. In addition, the (13)--D-glucan content was measured and in the case of G. arboreum the rate of (13)--D-glucan and cellulose synthesis was determined with [¹⁴C]sucrose as the precursor. For each of the species a similar chronology was obtained for the changes in content of the various non-structural carbohydrates. At the early stages of secondary wall formation, glucose and fructose exhibited a maximum which was closely followed by a maximum in the (13)--D-glucan content and in the sugar phosphates. On the other hand, the sucrose content increased regularly until fibre maturity. The rates of synthesis of (13)--D-glucan and of cellulose were highest following the maximum in the (13)--D-glucan content, when the latter was being depleted.Abbreviations DMSO dimethyl-sulphoxide - DPA days post anthesis - UDP-glucose uridinediphosphoglucose     

Sequential changes in the cyclic nucleotide levels and cyclic nucleotide phosphodiesterase activities during development ofMyxococcus xanthus

The levels of adenosine 3′,5′-monophosphate, guanosine 3′-5′-monophosphate and the activities of their respective phosphodiesterases exhibited changes during development ofMyxococcus xanthus that are substantially consistent with role postulated for each in a previously proposed model.     

Radiation resistance of motor-defensive conditioned reflexes in rats at different stages of the formation and stabilization of a temporary connection

Disturbances were studied of the motor defensive conditioned reflexes in rats radiated in a dose of 100 Gy at different stages of formation and stabilization of temporary connection. In comparison with consolidated (automatized) conditioned reflexes of active avoidance, early stages of formation and stabilization of the temporary connection are characterized by a relatively low resistance against extreme factors and by deepest disturbances of reproduction in radiated animals. The most probable mechanisms of these disturbances are connected with pathological changes of the nervous processes balance towards an increase of excitability and weakening of internal inhibition. Yet a direct radiation influence on the mechanisms of temporary connection reproduction at the second stage of its consolidation cannot be excluded. The role is shown of the emotional reactivity in the above-described processes.     

Localization of cyclic nucleotide phosphodiesterase in the multicellular stages of Dictyostelium discoideum

Cyclic 3',5'-adenosine monophosphate (cAMP) is secreted as the chemotactic signal by aggregating amoebae of the cellular slime mold Dictyostelium discoideum. We have used ultramicrotechniques in the biochemical analysis of cyclic nucleotide phosphodiesterase (PD) distribution in individual aggregates at various stages of development. With handmade constriction pipettes in microliter volumes, sections of lyophilized individuals weighing 20-100 ng could be assayed in a reaction coupled to 5'-nucleotidase. Phosphodiesterase activity was measured at pH 7.5 with 12 microM cAMP, cAMP-PD activity in aggregates ranged from 20-40 mmol/h/kg. In the pseudoplasmodium it had dropped to 5-10 mmol/h/kg and a difference in activity between the anterior prestalk cells and posterior prespore cells began to appear. The utmost posterior sections showed elevated phosphodiesterase from this stage onward. During culmination, activity rose to 40-60 mmol/h/kg associated with the developing stalk, while it declined in the spore mass. The papilla remained constant at 5-10 mmol/h/kg. The pattern of localization in the stalk was the same when cGMP was used as substrate. Extracellular phosphodiesterase inhibitor produced at the aggregation stage was found to reduce the localized activity in the culmination stage by 50-80%, with the most marked inhibition occurring in the center of the papilla. We found no evidence of endogenous heat-stable phosphodiesterase inhibitor within the culminating sorocarp.     

Genetic dissection of chlorophyll content at different growth stages in common wheat

Quantitative trait loci (QTLs) for chlorophyll content were studied using a doubled haploid (DH) population with 168 progeny lines, derived from a cross between two elite Chinese wheat cultivars Huapei 3 × Yumai 57. Chlorophyll content was evaluated at the maximum tillering stage (MS), the heading stage (HS), and the grain filling stage (GS), at three different environments in 2005 and 2006 cropping seasons. QTL analyses were performed using a mixed linear model approach. A total of 17 additive QTLs and nine pairs of epistatic QTLs were detected. Ten of 17 additive QTLs for chlorophyll content were persistently expressed at more than two growth stages, which suggest developmentally regulated loci controlling genetics for chlorophyll content in different growth stages in wheat. One novel major QTL for chlorophyll content was closely linked with the PCR marker Xwmc215 and was persistently expressed at three growth stages.     

Changes in the catecholamine content of brain structures in rats subjected to immobilization stress

The changes in DOPA and catecholamine (adrenaline, noradrenaline, dopamine) levels were investigated in noradrenaline- and dopamine-synthesizing brain nuclei of Wistar rats after prolonged immobilization stress on catecholamine analyzer (BAS, USA) using HPLC technique. Distinct DOPA and catecholamine changes were observed in locus ceruleus + nucleus subceruleus (1. c + n. sc) and substantia nigra at any stage after immobilization (right after immobilization and 15 and 30 days later). The most prominent alterations in noradrenaline content were detected in 1. c + n. sc. 30 days after immobilization NA level in these nuclei was 1.5 times higher, as compared to the control one. It is suggested that the increasing noradrenaline level in 1. c + n. sc. plays a defensive role in survival of rats after immobilization stress.     

A cytophotometric study of the RNA and glycogen content of human hepatocytes at different stages in the development of traumatic disease]

Absorption and fluorescent cytophotometry techniques were applied to studies of RNA, glycogen and its fractions in hepatocytes of patients with hard mechanic trauma, both with and without endointoxication. For measuring RNA and glycogen contents, slides were stained by gallocyanin-chromalum or underwent fluorescent PAS-reaction, respectively. The repeated aspiration biopsy material was used for investigation of RNA and glycogen contents in dynamics. A quick increase in RNA content took place at the first stage (within the first 3 days) of traumatic illness of both the groups of patients. At the second stage of illness the hepatocyte RNA content in patients without endointoxication was seen to decrease to the initial level, whereas that in patients with endointoxication increased from the initial level by 36%. At different stages of illness the total glycogen content is changed insignificantly in the course of illness, but its labile fraction decreases to 70% of the total glycogen in patients with endointoxication. The increase of hepatocyte synthetic activity and the maintenance of the normal glycogen level may suggest a sufficient compensatory possibility of the liver, in spite of a high functional load under endointoxication.     

Inhibition of the different cyclic nucleotide phosphodiesterase isoforms separated from rat brain by flavonoid compounds

A series of synthetic pentasubstituted analogs of quercetin were evaluated for their ability to inhibit the various phosphodiesterase isoforms resolved from rat brain cytosol by isoelectric focusing. All the tested compounds were more potent in inhibiting the calcium plus calmodulin-independent isoforms than the dependent ones. Out of the two calcium-independent cyclic AMP-specific isoforms present in brain preparations, the Rolipram-sensitive enzyme proved to be the most sensitive to flavonoid inhibition. In contrast with the antidepressant compound Rolipram which is totally devoid of anticalmodulin property, these flavonoid derivatives exhibited anticalmodulin activity as illustrated by their higher inhibitory potency toward the calmodulin-dependent isoform in the presence of calcium plus calmodulin than in the presence of EGTA and by the ability of [3H] penta-O-ethylquercetin to bind to calmodulin in a calcium-dependent way.     

The interaction of perception and attention at different stages in individual development

In the study carried out on children aged 10 years (51 persons), subjects aged 16-17 (11) and adults (19) characteristics of the perception and attention interaction were studied by means of electrophysiological parameters analysis (ERP, CNV, EEG) of the process of solution of various visual tasks. It has been shown that adequate brain provision of this process is based in adults both on the functional topographic differentiation and specialization of separate perceptive operations and on the possibility of controlling generalized and local activating influences according to task requirements. In children aged 10, not differing from the adults by the success of the perceptive activity, age peculiarities of its strategy are revealed connected with functional brain organization. Basic distinctive features of children perceptive activity are intensified regional specificity manifested both in responses to relevant and non-relevant stimuli, and excessive generalized activation testifying to incomplete structural-functional maturation of the frontal regions of the cerebral cortex. Increasing functional activity of these structures in ontogenesis provides for the selectivity of perceptive, cognitive and activating processes, adequate to the requirements of the task.