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     

Influence of Ca2+ and substance P on the (Ca Mg) ATPase (EC 3.6.1.3) activity of synaptosomes from different areas of rat brain

The influence of SP in vitro on the (Ca Mg) ATPase activity of synaptosomes from cerebral cortex, hippocampus, midbrain and thalamus with hypothalamus of rats was studied. It was confirmed that SP increases the activity of the enzyme from hippocampus, midbrain and thalamus with hypothalamus. A condition of this stimulation is the maintenance of Ca2+ concentration between 1 and 2 X 10(-4) M. Ca2+ concentration above and below the optimal (0.2 mM), reduced the SP stimulation of (Ca Mg) ATPase activity.     

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.     

Changes in pain reactions and 3H-naloxone binding to opiate receptors of the hypothalamus and midbrain in rats after repeated swimming in cold water

The dynamics of nociceptive reactions and character of 3H-naloxone binding to hypothalamus and midbrain synaptic membranes were studied in rats subjected to repeated cold swim stress (3 min. daily during 3, 5 and 15 days). It was shown that an increase of latencies of background nociceptive reactions (hot-plate and tail-flick tests) was accompanied by an ambiguous changes of kinetic parameters of 3H-naloxone binding in the studied brain structures. The results suggest that an increase of antinociceptive systems tone under repeated cold swim stress may be caused by a dynamic transformation of opiate u-receptor apparatus in various brain structures.     

Role of aminopeptidases in enkephalin catabolism: comparative study of the regional distribution of aminopeptidases and enkephalinase A in the rat brain

In order to elucidate the role of aminopeptidases in enkephalin catabolism in rat brain, the local distribution of two types of cerebral cellular membrane aminopeptidases (puromycin-sensitive and puromycin-insensitive ones) and of the enkephalin system marker, enkephalinase A, was studied. It was found that the distribution patterns of the former enzymes differ essentially from that of enkephalinase A. Study of coupling between the enzymatic activities in different regions of rat brain revealed a strong correlation between the activities of puromycin-insensitive aminopeptidase and enkephalinase A in midbrain (including hypothalamus). It was supposed that in midbrain the role of aminopeptidase M in intrasynaptic inactivation of enkephalins is much more conspicuous than in other regions of rat brain. The puromycin-sensitive aminopeptidase activity does not seem to play a role in enkephalin catabolism.     

Difference in the Pattern of Soluble Proteins from Rat Brain Regions

The electrophoretic pattern of soluble proteins from seven rat brain regions (amygdala, cerebellum, corpus striatum, cortex, hypothalamus, medulla, and midbrain) was examined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. Although the number of protein bands (36) was identical in all brain regions studied, there were differences in their relative densities, the greatest variation occurring in the low-molecular-weight region of the electrophoretogram. The bulk of the soluble proteins had molecular weights between 23,000 and 90,000 daltons. The medulla and amygdala showed the greatest range of protein band concentration. A large number of protein bands in the midbrain and corpus striatum showed a greater concentration of protein compared to the same bands in the other regions. A protein band that migrated with the same characteristic as albumin was found. It was consistently high in all regions, the midbrains showing a 1.5-fold greater concentration compared to other regions. Linear regression analysis of wet weight of regional brain tissue against protein concentration yielded a regression coefficient (r2) of 0.77. Midbrain and corpus striatum showed a relatively higher protein concentration: weight ratio than other regions.     

Antibodies to pathogenic epitopes on type XVII collagen cause skin fragility in a complement-dependent and -independent manner

In bullous pemphigoid (BP), the most prevalent autoimmune blistering disease, type XVII collagen (COL17) is targeted by circulating autoantibodies. BP is thought to be an autoantibody-mediated complement-fixing blistering disease, and a juxtamembranous noncollagenous 16A (NC16A) domain spanning Glu(490) to Arg(566) was proved to be the main pathogenic region on COL17, although precise pathogenic epitopes within NC16A have not been elucidated. In this study, we showed that injection of rabbit IgG Abs targeting Asp(522) to Gln(545) induced skin fragility associated with in vivo deposition of IgG and complement in neonatal COL17-humanized mice. Notably, immunoadsorption of rabbit anti-NC16A IgG Ab with this epitope (Asp(522) to Gln(545)) or the anti-NC16A IgG administered together with the peptides of this epitope as a decoy ameliorated skin fragility in the injected neonatal COL17-humanized mice compared with the anti-NC16A IgG alone even though all of the mice showed both IgG and complement deposition. These results led us to investigate an additional, complement-independent mechanism of skin fragility in the mice injected with anti-COL17 Abs. The rabbit anti-NC16A IgG depleted the expression of COL17 in cultured normal human keratinocytes, whereas immunoadsorption of the same IgG with this epitope significantly suppressed the depletion effect. Moreover, passive transfer of F(ab')(2) fragments of the human BP or rabbit IgG Abs against COL17 demonstrated skin fragility in neonatal COL17-humanized mice. In summary, this study reveals the importance of Abs directed against distinct epitopes on COL17, which induce skin fragility in complement-dependent as well as complement-independent ways.     

The effect of the aminopeptidase inhibitor bestatin on the enkephalin level in the rat brain

Met- and leu-enkephalin contents in midbrain (including hypothalamus) and striatum of rats were determined by radioimmunoassay after bestatin (racemate) injection (200 g, i.c.v.). It was found that bestatin administration influenced the midbrain met-enkephalin content, values and directions of the changes observed being dependent upon the time after the injection. The data obtained confirm the participation of aminopeptidase in enkephalin inactivation and present evidence for the possibility of regional variations of enkephalin catabolism pathways in the brain.     

Change of dopamine, serotonin and opioid neuromediator systems in the brain of rats adapted to prolonged effect of ethanol

AIM OF THE STUDY: To investigate the effect of in vivo short-term ethanol administration (i.p., 1.5 g/kg, 6 h) on binding characteristics of opioid receptor agonists in rat midbrain, as well as the contents of dopamine, serotonin and their precursors and metabolites in midbrain, striatum and hypothalamus of rats after long-term alcohol consumption. The methods of receptor binding assay and high performance liquid chromatography with electrochemical detection were used. The data obtained suggest that the response of neurotransmitter systems to short-term ethanol administration in different regions of rats brain is not identical. Our findings demonstrate that short-term ethanol administration may modulate dopaminergic transmission in the rat hypothalamus and striatum but this effect may be attenuated by down-regulation of OP, in the midbrain after long-term alcohol consumption. Serotonin system in hypothalamus becomes more sensitive to short-term ethanol administration after the long-term ethanol-containing liquid diet in comparison with control rats. Our results suggest that reinforcing properties of ethanol may be partially mediated by mechanisms involving the ethanol-induced disturbing of dopaminergic metabolism in the midbrain and hypothalamus and serotoninergic metabolism in hypothalamus.     

Regional differences in the turnover of neuronal histamine in the rat brain

The turnover rate of histamine (HA) and the half-life of neuronal HA were estimated in 9 regions of the rat brain following pargyline-induced accumulation of tele-methylhistamine (t-MH). The turnover rate was the highest in the hypothalamus (108.7 ng/g/hr). The striatum also showed a high turnover rate (80.2 ng/g/hr) despite much lower levels of HA and t-MH, as compared with the levels in the hypothalamus. The turnover rate was relatively high in the thalamus, cerebral cortex, amygdala and midbrain, but it was very low in the cerebellum. t-MH accumulation in the spinal cord was nil. The HA levels were reduced to various degrees (from nil to less than 40% of the control) by (S)-alpha-fluoromethylhistidine, depending on the regions studied. The neuronal HA content of each brain region was subsequently estimated, and the half-life of neuronal HA in each region was calculated. The half-life of neuronal HA was the shortest (7.7 min) in the striatum, while it was long (about 50 min) in the hypothalamus and thalamus. Half-life values of about 20 min were obtained in other regions. These results show the high levels of histaminergic activity in some parts of the telencephalon, thalamus and midbrain as well as the hypothalamus.     

Serotonin metabolism in the brain during sexual motivation and activation of the murine hypothalamo-hypophyseal-testicular system]

Serotonin metabolism was studied in male CBA mice during sexual arousal. It was shown that placement of a receptive female into a cage department separated from a male with a perforated partition, which prevented from the physical contact but allowed a male to see and smell a female, caused an elevation of serotonin metabolism. It was originally shown that 10-min female exposure produced in a male an increase in the level of the main serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the midbrain and its decrease in the hypothalamus. The catabolism coefficient (5-HIAA/serotonin ratio) also increased in the midbrain and decreased in the hypothalamus, while the serotonin content was unchanged. Longer sexual activation of male rats (for 20 min) resulted in an increase in the content of serotonin and 5-HIAA in the amygdala and olfactory bubs, while in the hippocampus only the level of 5-HIAA increased. Thus, for the first time, two stages were distinguished in male sexual arousal. They were determined according to the response of the pituitary-testicular system and involvement of serotonin in different brain regions.     

Distribution of immunoreactive mesotocin and vasotocin in the brain and pituitary of chickens

The distribution of vasotocin and mesotocin in the pituitary and central nervous system in male chickens was determined using radioimmunoassays. Neither peptide was detected in the pineal. Mesotocin, but not vasotocin, was detected in the cerebellum. Both peptides were found in the septal area, archistriatum, paleostriatum, optic lobe, anterior, medial and posterior hypothalamus, midbrain, pons, medulla oblongata, and the anterior and posterior pituitary. Equal amounts of the 2 peptides were present in the septal area, archistriatum and anterior hypothalamus whereas vasotocin was more abundant (2- to 10-fold) in the paleostriatum, optic lobe, midbrain, and pituitary. The amount of mesotocin was about twice that of vasotocin in the medulla oblongata and the medial and posterior hypothalamus. The wide distribution of vasotocin and mesotocin in extrahypothalamic sites in the central nervous system suggests that the peptides may, as in mammals, have a role in a variety of autonomic and endocrine regulatory processes in chickens.     

Responses of neurons of the frontal area of the cortex of the rabbit to electric stimulation of certain limbic-mesencephalic structures after administration of substance P

In rabbits tested on behavioural reactions by electrical stimulation of certain limbic-midbrain structures, intravenous injection of substance P (30 mcg/kg) led after 10 min of silent period to a decrease of spontaneous neuronal activity in the frontal cortex. Convergence of excitations arising from the lateral hypothalamus, the dorsal hippocampus and the midbrain reticular formation was also found to decrease after the substance P injection. Analysis of neuronal responses allowed to establish that substance P markedly changed the ascending excitations of the lateral hypothalamus and was less effective for the influences from the midbrain reticular formation.     

Isoforms of Aldehyde Dehydrogenase in the Brain Structures of Rats with Different Inclinations to Ethanol Consumption

We measured the levels of activity of aldehyde dehydrogenase (AdhDH, EC 1.2.1.3) manifested at different concentrations of acetaldehyde (AcAdh) in cytosol fractions from the tissues of the hypothalamus, midbrain, and neocortex of rats preferring an ethanol solution or pure water as liquids for drinking (ethanol- and water-preferring, EP and WP groups, respectively). Two AdhDH isoforms, with a high and a low affinity for AcAdh, were identified in the above brain structures. An AdhDH-1 isoform characterized by a higher affinity for AcAdh and a low value of the apparent Michaelis constant (K _m) was found in all studied brain structures of the EP rats. An analogous AdhDH-1 isoform found in cytosol fractions from the hypothalamus and midbrain of the WP rats showed a lower affinity for AcAdh and provided a lower maximum rate of reaction (V _max). In the neocortex cytosol fractions of the rats of this group, AdhDH-1 could not be identified. In EP rats, the level of AcAdh metabolism mediated by AdhDH was noticeably higher in cytosol fractions from the hypothalamus and midbrain, as compared with that in the respective fraction from the neocortex.     

Opioid peptide content of the brain and blood of rats under immobilization stress

A study was made of the influence of acute and repeated immobilization on the content of immunoreactive metenkephalin (ME), leu-enkephalin (LE) and beta-endorphine (beta-E) in different regions of rat brain and that of beta-E in rat blood. Acute immobilization for 30 min led to a decrease in the content of the enkephalins in the hypothalamus. Meanwhile 150-min immobilization caused a remarkable increase in the opioid concentration in the hypothalamus and of the enkephalins in the pituitary. At the same time the beta-E content in the pituitary dropped to 38% of the control (P less than 0.001), that in the blood was twice as increased (P less than 0.05). Repeated immobilization for 7 days abolished these changes in the hypothalamus and pituitraty. The next day following immobilization for 39 days the content of LE and beta-E in the hypothalamus, medulla oblongata, midbrain and blood plasma was noticeably lowered. However, after successive immobilization it rose to the control level. The data obtained are discussed in the light of the involvement of opiate systems in the realization of antinociceptive and emotional effects of stress.     

Neuroprotective effect of N-acylethanolamines in chronic morphine dependence. III. Influence on the content of neurotransmitters in the rat brain

The effect of the mixture of saturated and unsaturated N-acylethanolamines (NAEs) on the functional activity of catecholamine- and serotoninergic systems of the rat brain with experimental morphine dependence was investigated. A significant decrease of dopamine levels was found in the hypothalamus, midbrain and cortex of rats with morphine dependence. The administration of NAEs to rats with morphine dependence in time course dose of 35 mg/kg markedly increased the levels of dopamine in the hypothalamus, middle brain and cortex. Simultaneously the significant decrease of serotonine content was observed in the midbrain and cortex. The results obtained suggest that one of the important aspects of neuroprotective action of NAEs under morphine dependence is the restoration of dopamine content in the brain.     

Distribution of the kinin-breakdown activity in areas of the rat brain in the dynamics of spontaneous hypertension

Kinin-damaging activity (KDA) has been studied in 8 brain areas of normotensive rats and rats with spontaneous hypertension, aged 3 to 12 months. A significant depression in KDA was revealed in midbrain, striatum, thalamus, and pituitary body of normotensive rats 6 months of age, as compared to 3-month-old animals. A tendency towards KDA increase was noted in the hypothalamus. In 12-month-old normotensive rats KDA level returned to baseline (3 months of age). Comparison of KDA in rats with spontaneous hypertension aged 3 to 12 months has revealed no age-dependent differences and it is, therefore, believed that rats with spontaneous hypertension lack certain mechanisms inducing a considerable decrease of KDA in 6-month-old normotensive rats.     

Distribution of serotonin and its metabolites in the brain structures and immunosuppression in submissive mice

The development of submissive behaviour in C57BL/6J mice in the sensory contact model was associated with an increase in the content of serotonin (5-HT) in the amygdala, hippocampus, dopaminergic nuclei A11, A10, A9, as well as in the caudate nucleus and hypothalamus after 10 and 20 days of confrontations compared to the controls. The level of 5-HT metabolite 5-hydroxyindolacetic acid (5-HIAA) was significantly higher in the most structures examined after 20 daily encounters as compared to animals with experience of 10 confrontations. The time course of submission over 10 or 20 days resulted in an increase of 5-HIAA/5-HT ratio in the midbrain nucleus raphe, nucleus accumbens, A9 and hypothalamus. In mice immunised on the 10th or 20th day of confrontations, the immune response inhibition was observed while its level remained unchanged after more prolonged confrontations (40 days). Thus, the experience of defeats during 10 days shown to be accompanied with an activation of 5-HT system in a number of the brain structures, produced immunosuppression. With increasing number of confrontations the ratio 5-HIAA/5-HT was decreased in the same structures and a tendency to the immune response elevation appeared.