Structural and Functional Characteristics of Neurons in the Sensorimotor Cortex of Rats with Different Resistance to Emotional Stress

Wistar rats behaviorally active in the open field test (resistant to emotional stress) are characterized by polymorphism of neurons in layer V of the sensorimotor cortex and the presence of hyperchromatic cells, which probably determines resistance to emotional stress in these rats. Atrophy of hyperchromatic neurons reflecting transient inhibition of cell activity was noted in Wistar rats subjected to stress. In the sensorimotor cortex of behaviorally passive animals (predisposed to emotional stress) groups of densely packed hyperchromatic cells and pronounced pericellular edema were revealed. In these rats stress caused irreversible changes in cortical neurons and death of some cells. The presence of ischemic cortical neurons in rats subjected to emotional stress suggests that cerebral hypoxia plays a role in structural and functional disorganization of the sensorimotor cortex during emotional stress.     

Expression of the c-fos Gene during Emotional Stress in Rats: The Clocking Effect of Delta Sleep-Inducing Peptide

Emotional stress induced more marked increases in the expression of the c-fos gene in limbo-reticular structures of the brain in rats prognostically predisposed to emotional stress. I.p. doses of delta sleep-inducing peptide (DSIP) (60 nmol/kg) weakened the stress-induced expression of the c-fos gene. This effect was more apparent in animals predisposed to emotional stress, in which preliminary injections decreased stress-induced c-fos expression in the paraventricular hypothalamus and the medial and lateral parts of the septum. The decreased expression of the early gene c-fos in emotional stress after preliminary dosage with DSIP may reflect the leading mechanism of the anti-stress action of this peptide.     

The Effects of Delta Sleep-Inducing Peptide on the Intensity of Lipid Peroxidation and Xanthine Oxidase Activity in Rat Tissues during Cold Stress

Exogenous delta sleep-inducing peptide given i.p. to intact rats at a dose of 12 g/100 g decreased the levels of diene conjugates and Schiff bases in liver and brain tissues and had no effect on xanthine oxidase activity in these tissues. Cold stress was accompanied by increases in xanthine oxidase activity in rat liver and brain, with a consequent accumulation of diene conjugates and Schiff bases, as compared with intact animals. Preliminary administration of delta sleep-inducing peptide before three days of cold stress led to decreases in xanthine oxidase activity and lipid peroxidation products in the liver and brain, as compared with values in stressed rats. The protective effect of delta sleep-inducing peptide in stress is discussed.     

Individual Resistance to Cerebral Ischemia and Negative Effect of Emotional Stress on the Course of This Disorder

The ratio of low-activity and high-activity rats differed in autumn, winter, and spring litters. Initially more intensive cerebral blood flow in low-active rats and its more pronounced decrease after common carotid artery occlusion determined their higher sensitivity to cerebral ischemia (compared to high-activity animals). After 18-h immobilization stress cerebral blood flow decreased by 10-15%, which abolished the difference in the individual resistance to cerebral ischemia. Independently on emotional resistance, cerebral ischemia was not accompanied by the development of collateral blood flow in the acute period and caused death of 90% rats.     

Changes in Duodenal Lymphoid Structures in Rats with Different Levels of Behavioral Activity Treated with Delta Sleep-Inducing Peptide and during Acute Emotional Stress

The effects of delta sleep-inducing peptide (DSIP) on intestinal lymphoid formations were studied. Experiments were performed on 42 male Wistar rats which had previously been tested in an open field. The results of this test were used to divide the rats into behaviorally active (predicted to be stress-resistant) and passive (stress-susceptible) animals. Stress was applied by restraining the animals in boxes with electrical stimulation of the back for 1 h. Administration of i.p. DSIP to rats led to decreases in the number of eosinophils in animals of all experimental groups. In active rats of the control group, administration of DSIP produced increases in the numbers of small and intermediate lymphocytes which were greater than increases in passive rats. After acute stress, behaviorally active rats showed increases in the number of lymphoid cells, mainly due to small and intermediate lymphocytes. In passive rats, stress and injection of DSIP were followed by increases in the numbers of plasma cells in all the duodenal mucosal structures studied.     

Deltaran prevents an adverse effect of emotional stress on the course of cerebral ischemia in low-resistant animals

Local cerebral blood flow in the left hemisphere decreased most significantly in lowresistant Wistar rats preexposed to emotional stress. Deltaran selectively increased blood flow in the left hemisphere and improved blood supply to neuronal activity unit of the brain in these animals. This drug prevented progressive decrease in local cerebral blood flow in both hemispheres during the acute stage of ischemia. The effect of Deltaran was related to modulation of collateral blood flow and adequate blood supply to neuronal activity unit in the brain tissue. Deltaran decreased the mortality rate (by 62%) and alleviated the symptoms of cerebral ischemia. The positive effect of Deltaran was more pronounced in the left hemisphere. __________ Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 141, No. 5, pp. 499–502, May, 2006     

Correction of cerebral ischemia in low-resistant animals with an antistress drug Deltaran

Deltaran decreased the amplitude of EEG slow waves and restored neuronal reactivity after carotid artery occlusion in Wistar rats sensitive to cerebral ischemia. Deltaran had no effect on local cerebral blood flow. This drug increased blood supply to a unit of neuronal activity in the brain of intact animals during the acute stage of cerebral ischemia, provided 100% survival rate of rats with cerebral ischemia, and prevented the development of neurological symptoms in survivors. Animal experiments proved the possibility of correcting cerebral ischemia with antistress drug Deltaran. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 141, No. 3, pp. 259–262, March, 2006     

宫内暴露尼古丁对生后小鼠大脑皮层神经细胞凋亡的影响

目的研究宫内暴露尼古丁对生后小鼠大脑皮层神经细胞凋亡的影响。方法建立妊娠期宫内暴露尼古丁小鼠动物模型,观察生后21天小鼠大脑皮层组织结构变化,免疫组织化学方法和W estern b lot方法检测宫内暴露尼古丁模型大脑皮层caspase-3的表达。结果尼古丁组小鼠大脑皮层脑回厚度较对照组变薄(P<0.05),免疫组织化学法检测到大脑皮层caspase-3阳性反应物的平均光密度值在尼古丁组高于对照组(P<0.05),W estern b lot方法检测到大脑皮层caspase-3酶原(32KD)形式及活性片段形式(17KD、20KD)的相对表达量高于对照组(P<0.01)。结论孕期宫内暴露尼古丁激活生后小鼠大脑皮层神经细胞caspase-3的过表达,参与大脑皮层神经细胞凋亡。     

Morphofunctional Changes in Neurons in the Temporal Cortex of the Brain in Relation to Spatial Memory in Bulbectomized Mice After Treatment with Mineral Ascorbates

The effects of an antioxidant mixture of mineral ascorbates (MA) on the state of neurons in the temporal area of the cortex and the behavior of mice subjected to bulbectomy (BE) were studied; these mice, as demonstrated previously, are characterized by deficiency of spatial memory and the development of a neurodegenerative process in brain structures showing pathological changes in Alzheimer's disease. One month after BE, there were abnormalities in the cytoarchitectonics of the temporal area of the cortex, with loss of clarity of the boundaries between its layers because of dystrophy of pyramidal neurons and foci of loss of these cells. There were sharp increases in the numbers of neurons showing pyknosis, karyolysis, and vacuolysis on the background of decreases in neuronal density. Three weeks of treatment by addition of MA to the diet prevented the degradation of spatial memory in mice after BE and protected neurons in the temporal area of the cortex from degenerative changes. These results provide evidence for the possibility of prophylaxis of neurodestructive changes of the Alzheimer's type.     

短暂性全脑缺血后再灌注大鼠纹皮质血管c-Fos蛋白表达及CGRP和NGF的影响

目的研究外源性降钙素基因相关肽(CGRP)和神经生长因子(NGF)对短暂性全脑缺血后再灌注大鼠纹皮质血管c-Fos蛋白表达的影响,探讨CGRP和NGF对缺血神经元的作用机制。方法在全脑缺血后再灌注模型上,应用免疫组织化学结合显微图象分析检测了c-Fos蛋白表达。结果假手术组、缺血再灌注组、CGRP组、NGF组和CGRP+NGF组缺血后再灌注3h、1d时在纹皮质的血管及其附近未见c-Fos蛋白阳性反应。缺血后再灌注3 d时在纹皮质的血管及其附近,缺血再灌注组未见c-Fos蛋白阳性反应,但NGF组和CGRP组c-Fos蛋白阳性反应明显,合用CGRP和NGF组分别较NGF组和CGRP组c-Fos蛋白阳性反应明显增强。结论CGRP和NGF分别增强脑缺血后再灌注大鼠纹皮质血管c-Fos蛋白表达,二者联合应用强于单独应用,二者对保护缺血神经元可能有协同作用。     

Changes in the Volume of the Intercellular Space of the Cerebral Cortex in Conditions of Peripheral Stimulation in Rats

Changes in the volume of the intercellular space of the rat cerebral cortex in response to peripheral repetitive stimulation were studied. The volume of the intercellular space and its changes were assessed by a modification of the four-electrode impedance method. The results suggest that evoked electrical activity in the cerebral cortex was accompanied by 3-5% decreases in the volume of the intercellular space.     

Dizocilpine Blocks the Effects of Delta Sleep-Inducing Peptide-Induced Suppression of c-fos Gene Expression in the Paraventricular Nucleus of the Hypothalamus in Rats

The characteristics of the actions of the non-competitive blocker of NMDA receptors dizocilpine on the expression of the early c-fos gene in the paraventricular nuclei of the hypothalamus were studied in rats with different predicted susceptibilities to emotional stress in conditions of treatment with delta sleep-inducing peptide. The results showed that prior treatment with dizocilpine blocked reductions in c-fos expression induced by delta sleep peptide.     

Changes in the Activity of NO Synthase,Energy Metabolism Enzymes,and the Ultrastructure of Cerebral Cortical Neurons in a Model of Transient Ischemia

Experiments were performed on white male Wistar rats under Nembutal-urethane anesthesia. Transient ischemia (10 min) was produced by clamping of the carotid arteries. Some neurons in the parietal area of the cerebral cortex and endotheliocytes in blood vessels showed increases in NO synthesis and in the activity of energy metabolism enzymes (SDH, LDH). Changes in the ultrastructure of some neurons and synaptic formations provided evidence of a state of functional pressure, while changes in others indicated irreversible changes (disturbances in lipid metabolism and destructive changes in the nucleus and cytoplasm).     

人参皂甙对老龄大鼠大脑皮质AChE老龄性改变的影响

目的观察大鼠大脑皮质乙酰胆碱酯酶(AChE)阳性纤维的老龄性改变,探讨人参皂甙对其影响。方法24只雌性Wis青tar大鼠随机分为青年组、老龄组及给予人参皂甙的给药组。对各组大鼠大脑皮质进行AChE酶细胞化学染色,图像分析各组大鼠大脑皮质神经纤维AChE含量及AChE纤维的配布情况。结果老龄组大鼠大脑皮质神经纤维AChE平均光密度值较年组明显减少(p<0.01),AChE纤维面积百分比例下降,人参皂甙组大鼠大脑皮质神经纤维AChE平均光密度值较老龄组明显增加(p<0.01),纤维面积百分比例上升。结论人参皂甙可增加老龄大鼠大脑皮质纤维中AChE平均光密度值,促进纤维侧枝出芽和纤维网的生长及重建。     

Urine Antipyrine Metabolites in Rats with Different Resistance to Hypoxia Subjected to Cold Stress

We studied antipyrine metabolism in rats with different resistance to hypoxia during adaptation to cold stress. Changes in the concentrations of some antipyrine metabolites at low temperature were associated with individual resistance to hypoxia. In low-resistant rats, antipyrine metabolism was suppressed from day 5 of cold exposure to day 3 of the recovery period. In highly resistant rats, antipyrine metabolism was inhibited on day 3 of cold exposure, but returned to normal on day 3 of the recovery period.     

Neuron Activity in the Prefrontal Cortex of the Brain in Rats with Different Typological Characteristics in Conditions of Emotional Stimulation

Male Wistar rats were separated according to the emotional resonance method (groups of animals avoiding (altruists) and not avoiding (egotists) the pain cries of partner rats) and neuron activity in the prefrontal areas of the cortex was studied in the right and left hemispheres. Assessments were made of changes in the frequency of nerve cell spike activity (in relation to the baseline activity of neurons in sated animals) in rats subjected to one day of food deprivation and after electrical stimulation of emotionally positive (lateral hypothalamus) and negative (tegmentum of the midbrain) brain structures and after exposure to the pain cries of partner rats. The results of these experiments revealed a series of differences in the cell activities of the two groups of rats. In conditions of hunger, the discharge frequency in the altruists was higher than that in egotists. Cortical neuron responses to positive stimulation were greater than those to negative stimulation in rats of both groups. Intracerebral stimulation produced significantly greater increases in discharge frequency in neurons of both prefrontal areas of the cortex in altruists than in egotists. In both groups of rats, neurons in the right hemisphere responded to emotionally negative stimulation with significantly greater activation than cells in the left hemisphere, while activity in the left hemisphere was greater in conditions of emotionally positive stimulation. Altruists showed significantly greater neuron responses during exposure to pain cries from victim rats in both the right and left hemispheres. The responses of egotists to victim cries were not significantly different from baseline activity levels.     

宫内暴露尼古丁对生后小鼠大脑皮层凋亡相关基因Bcl-2和Bax表达的影响

目的研究宫内暴露尼古丁对生后小鼠大脑皮层神经细胞凋亡相关基因表达的影响。方法建立妊娠期宫内暴露尼古丁小鼠动物模型,免疫组织化学方法和W estern b lot方法检测宫内暴露尼古丁模型大脑皮层Bc l-2和Bax的表达。结果免疫组织化学法检测到大脑皮层的Bc l-2表达的平均光密度值和W estern b lot检测的平均灰度比值(Bc l-2/GAPDH)在正常对照组高于尼古丁组(P<0.05),而Bax表达的平均光密度值和平均灰度比值(Bax/GAPDH)在尼古丁组高于对照组(P<0.05)。结论孕期宫内暴露尼古丁激活小鼠大脑皮层促凋亡基因Bax表达,参与大脑皮层神经细胞凋亡。     

Effects of Prenatal Stress on Free-Radical Lipid and Protein Oxidation and Superoxide Dismutase Activity in Cerebral Cortex Neurons and Neuroglia in the Rat Brain

The processes of free-radical oxidation of proteins and lipids and superoxide dismutase activity were studied in neurons and neuroglia of the cerebral cortex in rats during ontogenesis and after prenatal stress. Regardless of age, normal animals were found to have higher levels of free-radical lipid and protein oxidation in neurons than in glia. This same pattern was also observed in relation to superoxide dismutase. After prenatal stress, the level of free-radical lipid oxidation decreased in 20-day-old rats in both neurons and neuroglia. Conversely, the level of free-radical protein oxidation products increased only in neurons, by an average factor of four. Superoxide dismutase activity in animals subjected to prenatal stress decreased significantly in neurons but did not change in neuroglia. Translated from Rossiiskii Fiziologicheskii Zhurnal imeni I. M. Sechenova, Vol. 94, No. 4, pp. 406–413, April, 2008.