Influence of gravitational overload and hypokinesia on the structure of the vascular bed of the stomach]

Under study were effects of gravitation stresses, total hypokinesia and their combinations on blood vessels of the stomach. The work was carried out in 130 rabbits, 16 of them being used to study the normal structure of the gastric vascular bed. The vascular bed was injected with the Gerota's mass followed by clearing, making histological preparations and roentgenography. The investigation has revealed both quantitative and qualitative changes in the structure of the gastric blood vessels. The maximum endurable stress of the ventro-dorsal direction causes morphological shifts less pronounced than stresses of longitudinal directions. With prolonged terms of hypokinesia (1-12 weeks) morphological changes became more pronounced in all the layers of the stomach. A combination of successive gravitation stresses and hypokinesia during 4-12 weeks aggravated morphological changes which occurred after exposure to isolated above factors. The animals subjected to maximum endurable stresses before and after 4-week hypokinesia developed vascular changes more typical for the effects of gravitation. The pretraining of animals did not give a pronounced positive effect on the changes of the angioarchitectonics of all the gastric layers after a repeated stress following 4-week hypokinesia.     

Comparative characteristics of the changes in resistance in the vessels of the skeletal muscle and small intestine after the destruction of the structures in the ventral portions of the medulla oblongata

Different trends and manifestation of changes of blood pressure and regional vessel resistance depending on the localization and the method (chemical or electrical) of the lesion in ventral medulla oblongata, were analyzed.     

Effect of general hypokinesia on the blood vessels of the medulla oblongata, pons and midbrain of the rabbit]

The work was performed on 40 rabbits. After injection of the blood system with Gerota's mass 120 mu horizontal sections were cleared after A. M. Malygin and stained with hematoxylin and eosin after Van Gieson. It was shown that within 1--3 weeks of staying in small cages the animals had dilated vein all areas of the brain under investigation. Within 4-12 weeks there appeared deformity, sharp sinuosity, disorders in usual orientation of vessels. Within 13-16 weeks of hypokinesia both qualitative and quantitative changes in blood vessels became more pronounced. It was also shown that readaptation for 1--3 weeks after 4--13 weeks of hypokinesia failed to repair the normal structure of blood vessels of the brain and that in all the parts under study the reactions of the circulatory bed structure to hypokinesia were of the same type.     

Effect of combined exposure to hypokinesia and gravitational stress on the structure of the wall of the renal vein

Renal veins from 25 rabbits were investigated by means of imbedding in paraffin with subsequent hematoxylin--eosin staining, after Van Gieson and with fuchselin after Hart. Prolonged hypokinesia (over 3 weeks) with subsequent single application of gravitational overloading was stated to produce some structural changes in the wall of the renal vein. They are manifested as loosening of the middle vascular sheath with vacuolization of myocytes and outgrowth of its elastic elements. Hypokinesia of longer duration (8 weeks) with subsequent gravitational overloading produces atrophy of smooth muscle tissue in the middle sheath of the venous wall that brings about decreasing in tonus of the wall of the renal vein.     

Effect of hypokinesia and the combined action of gravitational load and hypokinesia on the structure of the hepatic portal system]

General hypokinesia during 1--6 weeks resulted in dilatation of the interlobular veins. sinusoids and central veins. The sequence of alterations corresponded to terms of hypokinesia. After exposure to "gravitation stress--hypokinesia for 1--6 weeks" stagnation in the portal system of the liver was less than after exposure to hypokinesia alone, but unevenness of lumens in the interlobular veins and sinusoids was more pronounced. The foci of the vessel spasm were determined. The signs of stagnation in the system of the portal vein and unevenness of the width of all the links of the portal bed were most pronounced after combination "hypokinesia for 1--6 weeks-- gravitation stress".     

The effect of naloxone and delta-sleep inducing peptide on the homocarnosine content of brain tissue

The intraventricular and intravenous administration of naloxone was studied for its effect on the homocarnosine amount in cerebral hemispheres, striatum, hippocamp, hypothalamus, thalamus, cerebellum, medulla oblongata as well as in the spinal cord of rabbits. The intracysternal administration of naloxone decreases the homocarnosine amount in the striatum, hypothalamus, cerebellum and medulla oblongata. The intravenous administration of peptide exerts no statistically reliable effect on the homocarnosine content in the rabbit brain. The intraperitoneal administration of delta-sleep-inducing peptide increases sharply the homocarnosine content in the rat brain.     

Neonatal 6-hydroxydopamine treatment: noradrenaline levels and in vitro 3Hcatecholamine synthesis in discrete brain regions of adult rats

Endogenous noradrenaline levels are elevated in medulla oblongata, mesencephalon, pons and thalamus of adult rats which had been treated with 6-hydroxydopamine on days 1, 2, 8 and 15 after birth. Levels in spinal cord, cerebellum, hippocampus/amygdala and cortex are depressed, whereas no significant changes are observed in striatum, hypothalamus and medulla spinalis. The rate at which medulla oblongata synthesizes tritiated noradrenaline and dopamine from tritiated tyrosine $\text{in}$$\text{vitro}$ is markedly enhanced. No effect was apparent on catecholamine synthesis in hypothalamus. Tritiated noradrenaline synthesis, but not tritiated dopamine synthesis, in the cortex is depressed. These results support the view that neonatal 6-hydroxydopamine treatment causes a degeneration of noradrenaline nerve terminals in the cortex and induces an increase in noradrenaline terminals in the medulla oblongata.     

Cytochemical localization of alkaline phosphatase in the ependyma of the rat medulla oblongata

Summary The ependyma of the IVth ventricle and the central canal of the rat medulla oblongata was investigated using the cytochemical technique for alkaline phosphatase (AlPase) which revealed two types of ependymal cells in the medulla. The central canal type of the ependymal cell occupying the dorsal part of the central canal in the lower medulla exhibited intense AlPase activity with light microscopy. These cells had reaction products in all plasma membranes, including the microvilli and the cilia at the luminal cell surface. Some cells appeared to be tanycytes, since the process reached the basement membrane of the parenchymal blood vessel. The ventricular type of ependymal cells, which form the floor of the IVth ventricle and the central canal, contained no reaction products in any structure of the luminal cell surface.The possible relationship between the cerebrospinal fluid and the nervous tissues through the ependymal linings is discussed.     

Brain catecholamines at the early stage of emotional stress

The blood pressure (BP) dynamics and catecholamine (CA) levels in the brain regions of August and Wistar rats were studied two hours after immobilization in order to elucidate the central neurochemical mechanisms leading to the destruction of BR self-regulation under emotional stress during the experiment. The BP level did not differ from the normal. The CA concentration in the hypothalamus, midbrain, isthmus rhombencephali and medulla oblongata underwent considerable changes. It is suggested that the mechanism of the CA changes in both strains of the rats exposed to stress is similar in the hypothalamus and medulla oblongata while both strains of the rats studied showed specificity in the activity of NA-synthesizing neurons of the isthmus rhombencephali and DA-synthesizing neurons of the midbrain that might be a cause of different resistance of cardiovascular functions during the later stage of immobilization.     

Developmental Changes in the NGF Content in the Brain of Young,Growing, Low-Birth-Weight Rats

The NGF content in each region of the brain of four-week-old rats was ranked in the decreasing order of cerebral cortex, hippocampus, cerebellum, midbrain/diencephalon, and pons/medulla ob-longata, and the NGF concentration, in the decreasing order of hippocampus, cerebral cortex, cerebellum, midbrain/diencephalon, and pons/medulla oblongata in both AFD and SFD groups. The NGF content and concentration in the cerebral cortex were about the same value at each age between those in the AFD and SFD groups. Those in the hippocampus were a little higher in the SFD group than in the AFD group at the ages of three and four weeks, unlike those in the other regions, where the values for the cerebellum, midbrain/diencephalon and pons/medulla oblongata tended to be somewhat higher in the AFD group than in the SFD group. The NGF concentrations in the hippocampus and cerebral cortex increased with growth: the concentration in the hippocampus at four weeks of age was about 4-fold of that at one week in the AFD group and about 5.7-fold of that at one week in the SFD group; and likewise the concentration in the cerebral cortex at four weeks of age was about 5.3-fold in the AFD group and about 7-fold in the SFD group. The NGF concentrations in the cerebellum decreased, and those in midbrain/diencephalon and pons/medulla oblongata hardly changed with growth in either AFD or SFD group. From these results NGF may have stronger implications for the neuronal growth in the hippocampus compared with those in the lower brain regions of the SFD rats.     

Histometric changes in the liver of inbred rats during prevention of hypokinesis]

An experimental investigation on morphological changes in the liver under prophylaxis of hypokinesia has been performed in genetically uniform material--150 premature rats of August and Wistar lines. The prophylaxis has been carried out at hypokinesia as the background produced by training in the treadban and at the combination of the latter with a pharmacological stimulator. The experiment has been performed for two months. In histological preparations of the liver the number of hepatic lobules, hepatocytes and stellate reticuloendotheliocytes per unit of the tissue area have been determined. Nuclear diameters, width of hepatocytes and sinusoid blood capillaries have been measured. Significant histometric changes in structural components of the liver have been stated after 60 days of hypokinesia with decrease of the organ. Prophylactic measures applied with hypokinesia as the background produce certain positive effect, though it is not the same in different indices and in different strains of animals.     

Interleukin-1 increases norepinephrine turnover in the spleen and lung in rats

To clarify effects of interleukin-1 on sympathetic nerve activity, norepinephrine turnover in various organs was assessed in rats after intraperitoneal injection of recombinant human interleukin-1 beta. Interleukin-1 administration increased norepinephrine turnover in the spleen, lung and hypothalamus without appreciable effect in the heart, liver, submandibular gland, thymus, pancreas, brown adipose tissue and medulla oblongata. Similar changes in norepinephrine turnover were also found after the administration of bacterial endotoxin. It was concluded that interleukin-1 activates the sympathetic nerves specifically in the spleen and lung.     

Saralasin and SQ 20881 : their effects on central nervous system norepinephrine.

The effects of the infusion of Saralasin and SQ 20881, two drugs that inhibit the renin-angiotensin system, on the norepinephrine (NE) concentration in hypothalamus and medulla oblongata were studied in male Wistar rats. NE content increased in hypothalamus in response to both drugs, without changes in medulla oblongata catecholamine concentration. These results showed that the NE concentration of certain areas of the central nervous system can be modified, in a short time, by the inhibition of the renin-angiotensin system. Results observed after the infusion of Saralasin could indicate that the receptors, on which the angiotensin acts to produce this alteration, are similar to those of the peripheral blood vessels.     

The effect of psychotropic substances (aminazin, majeptil, trisedil) on protein synthesis in different regions of the rat brain]

Experiments were conducted on rats; a study was made of methionineS35 incorporation into the sum total proteins isolated from various portions of the brain after a single administration of chlorpromazine, majeptil and tricedil. A generalized depression of protein synthesis in all the structures, except the medulla oblongata, followed chlorpromazine administration in one and three hours. A stimulating effect is characteristic of majeptil in the majority of the brain portions. The action of tricedil was accompanied by reduction of methionine-S35 incorporation into the proteins of the majority of the brain structures and by an increase in its incorporation into the olfactory lobes. As supposed, changes in the protein synthesis in individual structures of the brain served as an important link in the action mechanism of psychotropic preparations on the organism.     

Changes in the alpha-adrenoceptors in the medulla oblongata including nucleus tractus solitarii of spontaneously hypertensive rats

The nucleus tractus solitarii (NTS) is a brain stem center mediating depression of blood pressure. In order to elucidate a possible mechanism for the central regulation of blood pressure, we studied noradrenergic indices in the medulla oblongata, a region including the NTS, in spontaneously hypertensive rats (SHR) as compared with normotensive controls of the Wistar Kyoto strain (WKY) at 12 weeks of age. The medulla oblongata was the only brain region showing a significantly low noradrenaline level in the SHR as compared with WKY rats; the level is also significantly decreased at 8 weeks of age. The alpha 1-adrenergic binding sites, as measured with 2-(2, 6-dimethoxy) phenoxyethylamine-methylbenzodioxan [³H]WB4101 showed significant increases inK _D andB _max values in medulla oblongata homogenates from rats of both strains from 4–12 weeks after birth, with no significant interstrain difference. On the other hand, theK _D andB _max of the alpha 2-sites, measured by [³H]yohimbine binding, were reduced in SHR as compared to WKY animals, even at 4 weeks after birth when hypertension was not yet apparent. As expected, the relatively selective alpha 2-antagonist, clonidine, was a potent inhibitor of [³H]yohimbine binding but not of [³H]WB4101 binding in these homogenates. The results suggest that some genetic disorder in the alpha 2-adrenergic transmission system in the NTS region may be involved in the development of hypertension in the SHR rats.Dedicated to Professor Yasuzo Tsukada.     

Morphology of the wall of some main arteries normally and in limited motor activity]

Effects of different periods of hypokinesia upon the structure of the main arteries wall and the microcirculatory bed of the aorta adventitia were studied in rabbits by histological methods. It was shown that hypokinesia lasting more than 4 weeks resulted in the atrophy of the medical sheath and dystrophy of the elastic framework in the wall of main arteries. In the microcirculatory bed of the aorta adventitia there occurred blood stagnation, the integrity of the microvessels wall (mainly capillaries, postcapillaries and venules) was broken. The degree of the above morphological changes depends on duration of hypokinesia.     

应激性高血压大鼠脑干及下丘脑-垂体-肾上腺轴中肾上腺髓质素及其受体mRNA表达的改变

采用逆转录-聚合酶链式反应检测了慢性足底电击结合噪声应激致高血压大鼠下丘脑、延髓、中脑、垂体和肾上腺等组织中编码肾上腺髓质素的肾上腺髓质素前肽原(preproadrenomedullin,ppADM)基因以及ADM的特异性受体组件降钙素受体样受体(calcitonin-receptor-like receptor,CRLR)和受体活性调节蛋白2和3(receptor-activty-modifying proteins,RAMP2和RAMP3)表达的变化.我们观察到:与对照组相比,以3-磷酸甘油醛脱氢酶作为内参照,15 d足底电击结合噪声应激引起下丘脑、垂体和肾上腺中ppADM mRNA表达上调,而在延髓和中脑表达明显下调(P＜0.01或P＜0.05);CRLR基因表达量正常时在下丘脑相对较高,应激15 d后CRLR表达在延髓、中脑和下丘脑下调(P＜0.01或P＜0.05),而在垂体和肾上腺的表达无明显变化;应激后RAMP2基因在延髓和下丘脑表达上调,而在肾上腺表达显著下调(P＜0.01),其他部位无明显变化;RAMP3基因在对照组大鼠的中脑和下丘脑表达较高,在应激性高血压大鼠的下丘脑和垂体表达上调(P＜0.01或P＜0.05),而在中脑和肾上腺表达下调(P＜0.05),在延髓中的表达变化无统计学差异.上述结果提示:慢性足底电击结合噪声应激引起明显的中枢和下丘脑-垂体-肾上腺轴ADM及其受体组件CRLR/RAMP2或CRLR/RAMP3基因的表达变化.但慢性应激后中枢源性ADM及其受体的表达变化对应激和血压的调节以及在应激致高血压中的确切作用及机制尚待进一步研究.     

应激性高血压犬鼠脑干及下丘脑-垂体-肾上腺轴中肾上腺髓质素及其受体mRNA表达的改变

采用逆转录- 聚合酶链式反应检测了慢性足底电击结合噪声应激致高血压大鼠下丘脑、延髓、中脑、垂体和肾上腺等组织中编码肾上腺髓质素的肾上腺髓质素前肽原(preproadrenomedullin, ppADM) 基因以及ADM 的特异性受体组件降钙素受体样受体(calcitonin-receptor-like receptor,CRLR)和受体活性调节蛋白2 和3(receptor-activity-modifying proteins, RAMP2 和RAMP3)表达的变化。我们观察到:与对照组相比,以 3- 磷酸甘油醛脱氢酶作为内参照,15 d 足底电击结合噪声应激引起下丘脑、垂体和肾上腺中ppADM mRNA表达上调,而在延髓和中脑表达明显下调(P<0.01 或 P<0.05); CRLR基因表达量正常时在下丘脑相对较高,应激15 d 后CRLR 表达在延髓、中脑和下丘脑下调(P<0.01 或 P<0.05), 而在垂体和肾上腺的表达无明显变化;应激后RAMP2 基因在延髓和下丘脑表达上调,而在肾上腺表达显著下调(P <0.01), 其他部位无明显变化;RAMP3 基因在对照组大鼠的中脑和下丘脑表达较高,在应激性高血压大鼠的下丘脑和垂体表达上调(P<0.01 或P<0.05), 而在中脑和肾上腺表达下调(P<0.05), 在延髓中的表达变化无统计学差异。上述结果提示:慢性足底电击结合噪声应激引起明显的中枢和下丘脑- 垂体-肾上腺轴ADM 及其受体组件CRLR/RAMP2 或CRLR/R     

Histochemical diagnosis of the neurons of cholinergic synaptic transmission

The authors studied neurons of the medulla oblongata of 5 human fetuses (22-27 weeks of development). Cholinacetyltransferase (CAT) activity was examined by the Berth method. Three neuronal types were diagnosed in the nuclei of the medulla oblongata with regard to CAT localization in the cytoplasm and synapses: (a) cholinergic-cholinoceptive neurons having CAT in the cytoplasm and in the innervating afferent fibers; (b) cholinergic-noncholinoceptive neurons with high CAT content, innervated with noncholinergic afferent fibers; (c) noncholinergic-cholinoceptive neurons carrying cholinergic synapses.