Effect of nembutal anesthesia,electric shock,and shock avoidance conditioning on acetylcholinesterase activity and protein content in various regions of the rat brain

Nembutal [pentobarbital sodium] was found to increase the protein content in some regions of the rat brain (posterior cortex, caudate nucleus) and to decrease the protein content in the ventral cortex. Acetylcholinesterase (AChE) activity, expressed in terms of wet tissue weight, increased in the cerebellum and medulla, but decreased in the medial cortex, hippocampus, thalamus, and the caudate nucleus. These changes in AChE activity were not explicable in terms of a direct effect of the anesthetic on the enzyme. A decrease in the protein content was observed in the frontal cortex, ventral cortex, hippocampus, and the caudate nucleus after electric shock is applied. Following shock avoidance conditioning, a decrease in protein content was observed in the medial cortex, posterior cortex, cerebellum, and the ventral cortex; the protein content increased in the thalamus. An increase in AChE activity was observed in the frontal cortex and in the medulla after shock, but its content decreased in the caudate nucleus, hypothalamus, thalamus, and the olfactory bulb. Following shock avoidance conditioning AChE activity increased in the posterior cortex, hippocampus, thalamus, and hypothalamus, but decreased in the ventral cortex.Translated from Zhurnal Evclyutsionnoi Biokhimii i Fiziologii, Vol. 15, No. 3, pp. 254–262, May–June, 1979.     

Altered pattern of immunohistochemical staining for glial fibrillary acidic protein (GFAP) in the forebrain and cerebellum of the mutant spastic rat

The spastic rat is a neurological mutant of the Han-Wistar strain with prominent spasticity, tremor, and ataxia. Neurodegeneration is found in the CA3 sector of the hippocampus and in Purkinje cells of the cerebellum. We examined the forebrain and cerebellum of spastic rats for glial reactions by using immunolabelling for the astrocytic marker, glial fibrillary acidic protein (GFAP). First, a map of the GFAP-distribution was made representing a systematic series of frontal sections in controls. Reactive astrocytes with increased GFAP should occur in the areas with established neuronal degeneration, but they could also demarcate further regions with pathology in this rat strain. Since the baseline levels of GFAP-immunoreactivity differ between brain regions, control rats and clinically normal littermates served as controls to judge relative increases in major structures. In the CA3 sector and hilus of the dorsal hippocampus, a massive gliosis was detected. In the cerebellum, a patchy increase of GFAP labelling in Bergmann glia was found. Further increases of GFAP-labelling in reactive astrocytes occurred in fiber tracts, the ventral thalamic nuclei, medial geniculate nuclei, pontine region and optic layer of the superior colliculus. Inconsistent changes were noted in cortex and pallidum. No defects of glial labelling or malformations in glial architectonics were found. The reactive changes of astroglial cells in hippocampus and cerebellum are in proportion to the neuronal degeneration. The glial reactions in the other brain regions possibly reflect a reaction to fiber degeneration and incipient neuronal degeneration or functional alterations of glial cells in response to neuronal dysfunction.     

Effect of starvation on insulin receptors in rat brain

To determine the effect of starvation on brain insulin receptors, rats were fed 4 g of chow/day for 14 days and then P2 fraction membranes were prepared from different brain regions. Compared to the fed state, there was an 18% reduction of insulin binding in olfactory bulbs from starved animals, but no change in the cerebellum, frontal cortex, amygdala, medial hypothalamus or lateral hypothalamus. A 15% reduction of olfactory bulb insulin binding was obtained by totally starving animals for four days. When membrane content was measured using the plasma membrane marker Na/K ATPase, insulin binding decreased by 26% and 14% in olfactory bulb membranes from starved and totally starved animals, respectively. The starvation-induced change in olfactory bulb binding was due to a loss of binding sites and not a decrease in binding affinity. Non-specific catabolism of protein and a change in the composition of membranes following starvation were excluded as causes for this effect. As streptozotocin induced diabetes had no effect on brain insulin binding, it was concluded that hypoinsulinaemia associated with starvation had not caused the reduction in olfactory bulb binding. Under similar conditions of starvation and diabetes, insulin binding in liver plasma membranes increased 26% and 38%, respectively. At 8 and 14 days of starvation, the reductions in olfactory bulb insulin binding and body weight were similar. On refeeding for three days, there was no increase in insulin binding, although body weight increased 7%. On refeeding for eight days, olfactory bulb insulin and body weight had returned to near normal.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of fetal thyroid states on RNA, DNA, and tubulin content in neonatal rat brain

3,5-Dimethyl-3'-isopropyl-L-thyronine (DIMIT)-induced fetal hyperthyroid rats showed a marked accumulation of intracellular tubulin content in the cerebral cortex, hypothalamus, and cerebellum at 1 day old. When the fetuses were transplacentally radio-thyroidectomized with the administration of [131I]-Na, the brain weight was not changed at 1 day old. The DNA content was not affected by the radio-thyroidectomy (Tx), but intracellular RNA concentration (per DNA) was increased in the hypothalamus and cerebellum at that age. The DIMIT-supplement to Tx-fetuses failed to restore these abnormal values to normal. Delayed effects of the fetal Tx were observed in 11-day-old infants. These neonates showed decreased weight gain in the body, brain, cerebral cortex, and cerebellum. The DNA content (per wet tissue) was higher in the hypothalamus and cerebellum. The intracellular concentrations of RNA and tubulin (per DNA) were significantly decreased in the hypothalamus. These values were restored to normal by the administration of L-thyroxine(T4) to rats between 1 and 10 days old. These results demonstrate that fetal nervous tissues are sensitive to changes in thyroid functions. The different manner of response to the hormonal states among the brain areas may reflect that each nervous tissue has a specific critical period for thyroid hormones during development.     

宫内感染后低龄大鼠脑组织中胶质纤维酸性蛋白的表达变化

目的:探讨胶质纤维酸性蛋白(GFAP)在宫内感染后低龄大鼠脑组织中的表达变化及其意义。方法: 对孕大鼠子宫内注入大肠杆菌建立宫内感染的大鼠模型,以子宫内注入生理盐水为对照组。两组分别于生后1、3、7、14及21 d取幼鼠脑组织,应用免疫组化方法检测脑组织中不同脑区GFAP的表达。结果: 生后1、3 d龄大鼠仅脑室旁白质区可见少许GFAP阳性细胞,两组细胞数无显著差异(P>0.05),其余脑区未见明显GFAP表达。感染组7日龄大鼠脑室旁白质和海马区GFAP阳性细胞数增多,与对照组比较差异显著(脑室旁白质区:9.73±3.55 vs 5.67±1.90,P<0.05;海马区:7.81±3.61 vs 2.16±1.11,P<0.05)。感染组14 d龄大鼠脑室旁白质、胼胝体及皮层区GFAP阳性细胞数增多,与对照组比较均有显著差异(脑室旁白质区:12.72±1.81 vs 9.00±0.93,P<0.01;胼胝体区:10.98±3.26 vs 4.44±1.15,P<0.01;皮层区:5.43±1.79 vs 2.71±0.67,P<0.01)。两组21 d龄大鼠各脑区GFAP阳性细胞数无显著差异(P>0.05)。结论: 宫内感染后低龄大鼠脑组织中GFAP表达增加。     

Histochemistry of glycogen deposition in perinatal rat brain: importance of radial glial cells

Summary Changes in the glycogen content and patterns of deposition in the developing rat brain were studied using a light microscopic periodic acid-Schiff method on embryonic days (ED) 14, 16, 18, 20 and postnatal days (PD) 1, 3, 7, 12, 16 and 21. Regional and temporal differences were quantified with an automatic image analyser by estimation of stained material in subpial regions of cerebral cortex, thalamus, superior colliculus and medulla. The cellular localization of glycogen particles was investigated by electron microscopy on ED 18, ED 20 and PD 2. On ED 14 the first signs of glycogen storage were found in parts of the immature choroid plexus and in radial glial cells in the midbrain and medullary raphé. With advancing foetal age these structures retained their high capacity for glycogen storage but, in addition, an increasing number of radial fibres in most of the brain stem regions and in the cerebral cortex of older foetuses (ED 18–20) showed significant amounts of glycogen. The storage of glycogen in cerebral cortex was relatively low at all foetal age intervals studied. In new born animals the distribution of glycogen particles was similar to that found in the late foetal brain. A decrease of glycogen content commenced from PD 1 to 3 and reached the pattern of the adult brain between PD 7 and 21.Glycogen storage by radial glial cells in the developing rat brain might indicate their possible role as an energy source in perinatal carbohydrate metabolism.     

Development of the basal forebrain cholinergic system: phenotype expression prior to target innervation.

We measured choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activities in the rat to determine the time course of development, maturity, and senescence of ChAT activity. Tissue was obtained from Sprague-Dawley rats ranging in age from embryonic day 14 through 23 months. Seven regions were examined, including the magnocellular preoptic/substantia innominata region, frontal cortex, medial septal region, hippocampus, diagnoal band, and medial and lateral striatum. ChAT and AChE activities were first detected as early as E18 in the medial septum, diagonal band and magnocellular preoptic area, all regions of cholinergic cell bodies. Enzyme activity subsequently developed in terminal fields of these cholinergic perikarya (hippocampus and frontal cortex) as well as in the striatum. For all regions, enzyme activity rose during the first four postnatal weeks. This increase in enzyme activity was transient and, in most instances, decreases were observed between postnatal days 30 and 60. Most dramatic were the decreases in enzyme activity in the magnocellular preoptic/substantia innominata and diagonal band regions. Age-related declines also occurred in the frontal cortex, hippocampus, magnocellular preoptic/substantia innominata region, and the striatum. Cholinergic systems undergo dynamic changes especially during development and adulthood.     

Regulation of Food Consumption during Pregnancy and Lactation in Mice

The aim of the present work was to assess the expression of agouti-like protein and neuropeptide Y in pregnant and lactating mice and to compare this with the leptin level and food consumption. Food consumption, blood leptin levels, and agouti-like protein and neuropeptide Y mRNA levels in the hypothalamus of C57Bl/6J mice were assessed on days 7, 13, and 18 of pregnancy and on days 10 and 21 of lactation, and in virgin females of the same ages. During pregnancy, food consumption and leptin levels decreased on day 7 and increased in day 18 of pregnancy, while neuropeptide Y mRNA levels increased on day 13 and then remained unaltered, and the agouti-like protein level increased on day 18. After parturition, food consumption continued to increase, while leptin levels and neuropeptide Y mRNA levels decreased to normal. Thus, hyperphagia in pregnancy was due to sequential activation of the expression of neuropeptide Y and agouti-like protein, while in lactation hyperphagia resulted from mechanisms not associated with changes in the expression of these neuropeptides.     

大鼠生后中枢神经系统S100B和胶质纤维酸性蛋白表达的变化

目的 探讨SD大鼠生后中枢神经系统发育过程中S100B和胶质纤维酸性蛋白(GFAP)的表达变化.方法 24只雄性SD大鼠分为生后7d、14d、21d和成年4组,用免疫组织化学方法对脑、脊髓切片进行S100B、GFAP抗体染色,观察不同时间点不同部位中两种阳性细胞平均数.结果 生后7d到成年,前额皮质、海马、纹状体、黑质和脊髓S100B阳性标记的密度和数量逐渐减少,生后2～3周时渐趋于稳定;脑内GFAP阳性星形胶质细胞(AST)随年龄增大逐渐增多,突起增粗增长,生后21d GFAP阳性细胞数量已接近成年;相反,脊髓GFAP阳性标记数则随年龄增长呈现由多到少的趋势;海马CAl区生后各年龄段GFAP和S100B免疫荧光双标显示,生后1周至成年S100B阳性细胞的数量明显减少,尤以分子层明显;随年龄增长,双标阳性细胞的比例逐渐增高,多集中分布于锥体细胞层和多形层.结论 大鼠中枢神经系统中S100B和GFAP两种星形胶质细胞蛋白存在不同的表达模式;同时S100B和GFAP蛋白的表达在发育过程中可能受不同机制的调节,并可能代表星形胶质细胞的不同亚型.     

Nuclear estrogen receptor binding in microdissected brain regions of female rats during pregnancy: Implications for maternal and sexual behavior

Previously, we showed that changes in nuclear estrogen receptor (NER) concentrations within large dissections of the preoptic area and hypothalamus of pregnant rats might underlie changes in both maternal and sexual behaviors. To more precisely localize these biochemical changes, NER concentrations were measured in microdissected nuclei within the preoptic area and hypothalamus of pregnant rats on days 8, 16 and 22. Results indicated that NER levels changed significantly throughout pregnancy and that the magnitude and direction of change was site specific. Although a different pattern of change was found in each nucleus, NER levels in most preoptic area nuclei were significantly higher by the 16th day of pregnancy compared to those on day 8, while receptor levels in most hypothalamic nuclei did not increase until day 22 of pregnancy. The higher NER levels found in preoptic area nuclei of female rats as pregnancy advances can be correlated with growing maternal responsiveness during pregnancy, while elevated concentrations of NER in hypothalamic nuclei at the end of pregnancy may indicate preparation for postpartum estrus.     

雌三醇对胚胎小鼠脑发育的影响

用免疫吸附及免疫组织化学方法研究了在妊娠期给予雌三醇对小鼠胚胎脑发育的影响。免疫定量结果表明：在小鼠生后１４ ｄ,雌三醇可增加神经元特异性标记物 神经元特异性烯醇化酶及神经丝的表达,而神经胶质细胞特异性标记物 神经胶质纤维酸性蛋白不受影响。免疫组织化学反应结果表明：雌三醇增加了位于视束前区,下丘脑视交叉上核、腹内侧核以及杏仁核等结构神经元的神经元特异性烯醇化酶的阳性反应强度,也增加了位于视束前外侧核神经元的神经丝反应强度。雌三醇除了明显减少了海马神经胶质细胞的神经胶质纤维酸性蛋白的表达外,在脑的其它区域对该抗原的反应性未见影响。本研究结果表明：妊娠期给予雌三醇可影响胚胎脑“性中枢”（ＰＯＡ ＡＭ ＢＨ ＡＭ 功能复合体）的发育。     

甲基苯丙胺对相关脑区的神经毒性作用

目的:研究甲基苯丙胺(MA)对大鼠纹状体、海马、额叶皮质等脑区神经细胞的毒性作用以及对大鼠行为的影响。方法:H-E染色、Glees银浸染观察神经元和轴突的变化;高效液相色谱检测上述脑区多巴胺(DA)及其代谢产物含量;免疫组化胶质纤维酸性蛋白(GFAP)检测胶质细胞增生情况。结果:MA对上述脑区神经细胞和轴突有损伤作用,表现为神经细胞变圆,极性消失;胶质细胞增生,噬神经细胞现象、胶质小结形成;神经轴索扭曲,节段性增粗,轴索间隙增宽;GFAP阳性星形细胞增多;纹状体DA及其代谢产物含量显著降低,海马、额叶皮质DA含量明显降低;大鼠行为改变明显。结论:MA对大鼠中枢神经系统多脑区神经元有明显的毒性作用,可导致上述脑区DA含量下降和大鼠行为改变。     

Glial fibrillary acidic protein immunoreactivity following cortical devascularizing lesion.

Disruption of a restricted area of the pia-arachnoid compromises vascular irrigation of the underlying cortex, leading to infarction of the tissue. This study was undertaken to examine the effects of such brain injury on glial cells. Adult male Wistar rats were processed for glial fibrillary acidic protein immunoreactivity at 1, 4, 7, 15 and 30 days after undergoing cortical devascularization. One day post-lesion, glial fibrillary acidic protein-positive cells were observed only at the lesion site. Glial fibrillary acidic protein-positive cells were present in the ipsilateral remaining cortex, distant from the wound, between days 4 and 15, and were also evident in the thalamus beginning 4 days post-lesion. These diverse temporal patterns of GFAP immunoreactivity in different brain structures suggest that various mechanisms can mediate increased GFAP immunostaining following injury.     

Influence of aging on catecholamine levels, accumulation, and release in F-344 rats

Neuronal function in selected brain areas has been evaluated in Fischer 344 rats aged 2-4 months, 11-14 months and 21-26 months. In vitro release of 3H-norepinephrine from hypothalamus and occipital cortex and 3H-dopamine from striatum has been evaluated using potassium, amphetamine, and field-stimulation. In vitro uptake of 3H-catecholamines has been evaluated in the same tissues. Catecholamine levels were measured in six brain areas: hypothalamus, striatum, cortex, cerebellum, brainstem and midbrain. Significant age-related decreases of NE levels, uptake, and release to high frequency stimulation were seen in the hypothalamus. The decreases in 3H-NE uptake and NE levels in the hypothalamus were apparent at 12 months, whereas the decrease in 3H-NE release after high frequency stimulation was seen in the senile rats.     

Insulin-like growth factor I receptors and estrogen receptors colocalize in female rat brain

Several findings indicate that there is a close interaction between estrogen and insulin-like growth factor I in different brain regions. In adult brain, both estrogen and insulin-like growth factor I have co-ordinated effects in the regulation of neuroendocrine events, synaptic plasticity and neural response to injury. In this study we have qualitatively assessed whether estrogen receptors and insulin-like growth factor I receptor are colocalized in the same cells in the preoptic area, hypothalamus, hippocampus, cerebral cortex and cerebellum of female rat brain using confocal microscopy. Immunoreactivity for estrogen receptors alpha and beta was colocalized with immunoreactivity for insulin-like growth factor I receptor in many neurons from the preoptic area, hypothalamus, hippocampus and cerebral cortex. Furthermore, estrogen receptor beta and insulin-like growth factor I receptor immunoreactivities were colocalized in the Purkinje cells of the cerebellum. Colocalization of estrogen receptor beta and insulin-like growth factor I receptor was also detected in cells with the morphology of astrocytes in all regions assessed. The co-expression of estrogen receptors and insulin-like growth factor I receptor in the same neurons may allow a cross-coupling of their signaling pathways. Furthermore, the colocalization of immunoreactivity for estrogen receptor beta and insulin-like growth factor I receptor in glial cells suggests that glia may also play a role in the interactions of insulin-like growth factor I and estrogen in the rat brain.In conclusion, the co-expression of estrogen receptors and insulin-like growth factor I receptors in the same neural cells suggests that the co-ordinated actions of estrogen and insulin-like growth factor I in the brain may be integrated at the cellular level.     

Effect of Imipramine and Prolyl Endopeptidase Inhibitor Benzyloxycarbonyl-Methionyl-2(S)-Cyanopyrrolidine on Activity of Proline-Specific Peptidases in the Brain of Rats with Experimental Anxious-Depressive Syndrome

Activities of prolyl endopeptidase and dipeptidyl peptidase IV in the frontal cortex, hypothalamus, nucleus accumbens, striatum, and hippocampus were measured in rats with the experimental anxious-depressive syndrome induced by treatment with a dipeptidyl peptidase IV inhibitor during the early postnatal period (days 5-18). Prolyl endopeptidase activity was elevated in the frontal cortex, hypothalamus, and nucleus accumbens. Increased activity of dipeptidyl peptidase IV was observed in the hypothalamus and striatum. Norepinephrine/serotonin reuptake inhibitor, imipramine, and noncompetitive prolyl endopeptidase inhibitor, benzyloxycarbonyl-methionyl-2(S)-cyanopyrrolidine, were shown to abolish depression-like behavior of animals in the forced swimming test. These compounds had a normalizing effect on activities of prolyl endopeptidase and dipeptidyl peptidase IV in brain structures of rats.     

Age-dependent alteration in regional cerebrovascular permeability during drug-induced epilepsy.

Age-related changes in blood-brain barrier permeability were investigated during pentylenetetrazol-induced seizures in rats aged from 15 days to 120 days. Tracers such as [14C]sucrose and [3H]inulin which diffuse very slowly across the intact endothelium were simultaneously injected i.v. in rats treated with pentylenetetrazol (PTZ) or in control animals. Permeability-surface area products (PA) were determined in 9 brain regions. Pentylenetetrazol-induced seizures caused a significant increase in PA for both sucrose and inulin in all brain regions studied. Blood-brain barrier dysfunction was present only in animals in which the mean arterial blood pressure rose at seizure onset. Although increased blood-brain barrier permeability was found partly in similar areas in both young and adult rat brains, in adults the increase was the highest in the preoptic area, septum, colliculus inferior, hypothalamus and in the cerebellum while the increase was comparatively much smaller in the same areas of young brains. The increase in blood-brain barrier permeability was extremely high in the hippocampus, hypothalamus and cerebellum of 15-day-old rat brain and, was least affected in the corpus striatum and cerebral cortex in contrast to older rats. From the results obtained it may be concluded that the increased cerebrovascular permeability induced by pentylenetetrazol differs markedly in localization in young and adult rats. The age-dependent increased blood-brain barrier integrity is not over all dependent on variations in the blood pressure, but rather on progressive maturation of capillaries and changes in their internal structure, and local phenomena in neuronal activity during the seizures.     

Effects of intraperitoneal administration of IFN-alpha for one, four, and fourteen days on amino acid levels in various rat brain regions.

Interferon-alpha (IFN-alpha) therapy is strongly associated with certain adverse effects, but the pathophysiologic mechanism is unclear. The present study was designed to investigate the influence of peripherally administered IFN- alpha on amino acid levels in the brain. IFN-alpha was administered intraperitoneally (i.p.) once daily to rats, and their brains were extracted 24 h after the last injection. The levels of glutamate, glycine, taurine, gamma-aminobutyric acid (GABA), and arginine in homogenized samples of the frontal cortex, striatum, hippocampus, amygdala, thalamus, hypothalamus, cerebellum, and brainstem were determined. One day of IFN-alpha treatment induced no significant changes in any of these amino acids. After 4 days of injections, glutamate, glycine, taurine, and gamma-aminobutyric acid levels were significantly higher than those in the control frontal cortex, striatum, hippocampus, amygdala, and thalamus. However, most of these amino acids returned to approximately basal levels, or even lower, with 14-day treatment. Our results suggest that daily peripheral administration of IFN-alpha affects the metabolism of amino acids in the brain. Further studies are necessary to determine if these effects of IFN-alpha on cerebral amino acids are involved in the pathophysiology of IFN-alpha-induced depression.     

Content of acid proteins in neuron and glial cell nuclei of the rat hypothalamus during cold adaptation

The content of acid proteins in nuclei of neurons and glial satellite cells in the medial preoptic region and supraoptic nucleus of the rat hypothalamus was studied by two-wave cytospectrophotometry on the 1st, 3rd, 7th, and 15th days of adaptation of the animal to cold (temperature 2–4°C). Cooling led to an initial decrease in the content of nuclear proteins in the whole neuronal-neuroglial system of the medial preoptic region, followed by gradual restoration to normal by the 15th day of cooling. In the glial cells of this region, before the return to normal there was a temporary increase in the content of acid proteins above the control level. In the neuronal-neuroglial system of the supraoptic nucleus a gradual accumulation of acid proteins was followed by a return to the control level. By the 15th day of the rats' stay in the cold, the content of neuronal and glial acid proteins of this nucleus fell somewhat below the control level.Department of Biochemistry, Rostov-on-Don University. Laboratory of Functional Neurochemistry, I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. (Presented by Academician V. N. Chernigovskii.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 86, No. 8, pp. 187–190, August, 1978.