Ultrastructural appearance of glycogen in the hypothalamus of the rabbit following chlorpromazine administration

Summary The tuber cinereum of hypothalamus, cerebral cortex, cerebellar cortex and caudate nucleus of rabbits were examined under the electron microscope following intramuscular administration of chlorpromazine with special consideration of ultrastructural changes in amount and distribution of glycogen granules in their hypothalamus. In these regions, normal astrocytes and their processes contain glycogen granules diffusely scattered in the cytoplasm. In the neurons of the normal hypothalamus and cerebellar cortex, glycogen granules are seen in some presynaptic endings and distal parts of dendrites but not in the perikaryal cytoplasm. In the tuber cinereum of the hypothalamus, after chlorpromazine administration, abundant glycogen granules accumulate at the postsynaptic sites, especially in peripheric parts of dendrites, and clusters of glycogen granules appear in the perikaryal cytoplasm of the nerve cells. These findings are interpreted as an increase of glycogen in these cellular regions and the suggestion is made that chlorpromazine inhibits the glycolytic metabolism in the distal parts of dendrites, particularly at postsynaptic sites and in the perikarya of nerve cells of the hypothalamus.     

Effect of cisplatin on rat placenta development

We examined the sequential histopathological changes in the placenta from rats exposed to cisplatin. Cisplatin was intraperitoneally administered at 2 mg/kg/day during GDs 11–12 (GD11,12-treated group), or GDs 13–14 (GD13,14-treated group), and the placentas were sampled on GDs 13, 15, 17 and 21. Fetal mortality rates were increased up to approximately 65% from GD 17 onward, and fetal weights were decreased on GD 21 in the GD11,12-treated group. A reduction in placental weights was detected from GD 15 onward, and the placentas on GD 21 were macroscopically small and thin in both treated groups. Histopathologically, in the GD13,14-treated group, an increase in apoptotic cells was detected on GDs 15 and 17 in the labyrinth zone, and on GD 21 in the basal zone, resulting in labyrinth zone hypoplasia. By contrast, in the GD11,12-treated group, an increase in apoptotic cells was detected on GDs 13, 15 and 17 in the labyrinth zone, and during the experimental period in the basal zone. A decrease in Phospho-Histone H3 positive cells was detected on GD 13 in the labyrinth zone and basal zone, resulting in hypoplasia of the labyrinth zone and basal zone. In addition, a marked decrease in glycogen cell-islands in the basal zone was also detected on GDs 15 and 17. There was a reduction in interstitial invasion of glycogen cell-like trophoblasts into the metrial gland on GD 15, resulting in metrial gland hypoplasia. Therefore, we consider that cisplatin administration in pregnant rats induces growth arrest of the labyrinth zone and basal zone, leading to small placenta. It is assumed that metrial gland hypoplasia is secondarily induced by the failure of glycogen cell island development associated with basal zone hypoplasia.     

Effect of methotrexate on rat placenta development

The sequential changes in the placenta from rats exposed to methotrexate were examined histopathologically. Methotrexate was intraperitoneally administered at 0.2 mg/kg/day during gestation days (GDs) 11–12 or GDs 13–14, and the placentas were sampled on GDs 13, 15, 17 and 21. The fetal mortality rates tended to increase throughout the experimental period, and fetal weights were significantly decreased on GD13 in the GD11,12-treated group. A significant reduction in placental weights was detected on GDs 13 and 15 in the GD11,12-treated group. Histopathologically, in the GD11,12-treated group, a significant thinning of the basal zone was detected throughout the experimental period, whereas the thickness of the labyrinth zone decreased significantly during GDs 13–17. The severity of thinning of the basal zone was higher than that of the labyrinth zone. In addition, a marked decrease in glycogen cell-islands in the basal zone was detected on GD 15. A significant decrease in Phospho-Histone H3-positive cells and a significant increase in terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells were detected on GD 13 in the basal zone of the GD11,12-treated group. In the GD13,14-treated group, there were no other significant changes in placentas and fetuses throughout the experimental period other than thinning of the labyrinth zone on GD 17. These results suggest that component cells of the basal and labyrinth zones during GDs 11–12 are more highly sensitive for methotrexate than those during GDs 13–14 and methotrexate affects the component cells of basal zone more strongly than those of the labyrinth zone.     

The cranial venous system in the rat: anatomical pattern and ontogenetic development

Summary The anatomical pattern and development of the venous system of the cranial base in the rat is described. The anatomy of the venous system was determined from observations of vascular casts in adult ratss; the development of the vascular system was established by examination of ink-injected embryos. A transverse sinus system was found to be present in the basal venous system. The sinus connects the posterior facial veins; its middle section transverses the cranial base through the basisphenoid canal, and it receives the venae ophthalmicae within the basisphenoid bone. The venae ophthalmicae in turn are connected to the perioptic veins and to the sinus interperiopticus intracranially. Dorsally, the venae ophthalmicae anastomose with the paired sinus cavernosus. The term sinus transversus basalis is proposed for the venous connection between the posterior facial veins within the basisphenoid bone of the rat. The anlage of the sinus transversus basalis is established by vascular networks during the final prenatal period, its formation, however, is only completed postnatally. The anlages of the venae periopticae, the venae ophthalmicae, the sinus cavernosus and the rami intercavernosi are already established at early developmental stages. The characteristic pattern is formed before birth.On leave from the First Department of Anatomy, Semmelweis OTE Budapest, Hungary     

Nicotinamide prevents the long-term effects of perinatal asphyxia on basal ganglia monoamine systems in the rat

Asphyxia during birth can cause gross brain damage, but also subtle perturbations expressed as biochemical or motor deficits with late onset in life. Thus, it has been shown that brain dopamine levels can be increased or decreased depending upon the severity of the insult, and the region where the levels are determined. In this study, perinatal asphyxia was evoked by immersing pup-containing uterus horns removed by hysterectomy in a water bath at 37°C for various periods of time from 0 to 20 min. After the insult, the pups were delivered, given to surrogate mothers, treated with nicotinamide, further observed and finally, 4 weeks later, killed for monoamine biochemistry of tissue samples taken from substantia nigra, neostriatum and nucleus accumbens. The main effect of perinatal asphyxia was a decrease in dopamine and metabolite levels in nucleus accumbens, and a paradoxical increase in the substantia nigra. Nicotinamide (100 mg/kg i.p., once a day for 3 days, beginning 24 h after the perinatal asphyctic insult) prevented the effect of asphyxia in nucleus accumbens. Furthermore, striatal dopamine levels were increased by nicotinamide in asphyctic animals. No apparent changes were observed in substantia nigra. A prominent unexpected effect of perinatal asphyxia alone was on the levels of the metabolite of 5-hydroxytryptamine, 5-hydroxyindoleacetic acid (5-HIAA), which were increased in substantia nigra and decreased in both neostriatum and accumbens. However, nicotinamide increased 5-HIAA levels in all regions, which appeared to be related to the extent of the asphyctic insult. These results suggest that nicotinamide is a useful treatment against the long-term consequences produced by perinatal asphyxia on brain monoamine systems, and that there is a therapeutic window following the insult, providing a therapeutic opportunity to protect the brain. Electronic Publication     

The post-exercise recovery of triglycerides in rat tissues

Summary Triglycerides (TG) recovery after exhaustive muscular exertion was investigated in tissues of fed rats and rats fasted for 24 h before exercise. In both groups the exercise caused reduction of TG level in the fast-twitch-oxidative-glycolytic (FOG) muscle, in heart muscle, and in plasma and accumulation of TG in liver.In the fed group the level of TG in FOG muscle, in liver, and in plasma normalized after 1 h of recovery, but only after 3 h in heart muscle. Treatment with glucose somewhat slowed down this process in FOG muscle. In the fasted group, the level of TG in each tissue returned to the pre-exercise value after 3 h of recovery.The work was supported by Polish Academy of Sciences, project 10.4.2.01.3.2.     

Nestin在成年大鼠基底前脑表达的鉴定

目的鉴定巢蛋白(Nestin)在成年大鼠基底前脑的表达。方法应用小鼠抗大鼠Nestin单克隆抗体(Rat401)对成年大鼠基底前脑进行了免疫组织化学研究和Westen-blot检测。结果Nestin免疫反应阳性神经元广泛分布于成年大鼠基底前脑的隔-斜角带(MS-DBB)复合体,基底前脑MS-DBB复合体的内侧隔核(MS)、斜角带垂直支(vDB)和斜角带水平支(hDB)分别有一相对分子质量约为240000的单一蛋白带。结论成年大鼠基底前脑MS、vDB和hDB均存在Nestin表达。     

Effect of exercise on glycogen metabolism in muscles of triiodothyronine-treated rats

The aim of the present study was to examine the rate of glycogen mobilization during exercise and the rate of the postexercise glycogen replenishment in different muscle types [white (WG), and red (RG) gastrocnemius, soleus (S) and diaphragm (D)] in rats treated with triiodothyronine (T₃, group T). Rats of the control group (C) were treated with saline. The animals were made to run on a treadmill set at 0° gradient and at a speed of 1200 m·h^–1. The time taken to reach exhaustion in group C was 188 (SD 23) min, whereas in group T, it was only 63 (SD 12) min. The content of glycogen in all muscles of the rats from group T at rest and during exercise was significantly lower than in group C at each corresponding time. At exhaustion, the glycogen content was in WG(C) 34.79 (SD 4.65), (T) 20.10 (SD 4.10); in RG(C) 22.82 (SD 4.66), (T) 16.50 (SD 2.00); in S(C) 14.85 (SD 2.48), (T) 11.90 (SD 2.93); in D(C) 18.18 (SD 3.49), (T) 7.54 (SD 3.36) (mol of glucosyl units·g^–1). The amount of glycogen mobilized during exhausting exercise in RG, S and D was similar in both groups whereas in WG it was much higher in rats of group T than in group C. The concentration of glycogen returned to pre-exercise values in each muscle 3 h after exercise. The net amount of glycogen resynthetized during 3 h of recovery depended on the muscle type. It was in WG(C) 3.30, (T) 18.03; in RG(C) 21.34, (T) 25.88, in S(C) 34.00, (T) 17.68, and in D(C) 17.25, (T) 12.22 mol of glucosyl units·g^–1 (each number represents the difference between the means). It concluded that treatment with T₃ markedly affects this exercise-induced metabolism of glycogen in each muscle type.From our study it is suggested that low muscle glycogen content may contribute to a reduction in exercise performance in hyperthyroidism.     

Effects of pinealectomy and exogenous melatonin on rat hearts

The effects of pinealectomy and administration of melatonin, the major secretory product of the pineal gland, which is a direct free radical scavenger and an indirect antioxidant, were studied in rat hearts on the basis of cardiac morphology and biochemical findings. Three groups of Wistar rats were used: one group was the sham-operated control, one group consisted of pinealectomized rats and one group consisted of pinealectomized rats that were treated with melatonin. Serum cholesterol, tissue levels of malondialdehyde (MDA) and reduced glutathione (GSH), and heart weight were determined. Histochemical staining with the Van Gieson, PAS/Alcian blue at pH 2.5 and Masson's trichrome methods were performed in addition to hematoxylin-eosin staining. Levels of serum cholesterol and tissue MDA, and heart weight were increased in pinealectomized rats whereas GSH levels did not change. Melatonin administration reversed these effects. Microscopically, myocardial fibrosis and myxomatous degeneration of cardiac valves were detected in all pinealectomized rats. It can be concluded that pinealectomy of rats causes morphological changes in rat hearts, and short-term application of melatonin does not reverse these changes.     

神经激肽B在成年大鼠基底前脑Nestin阳性神经元的表达

目的观察基底前脑Nestin-IR神经元是否表达神经激肽B(NKB),探讨基底前脑Nestin-IR神经元的递质属性。方法应用免疫组织化学双标染色方法,观察10只SD大鼠基底前脑的Nestin-IR神经元是否表达NKB。结果Nestin-IR神经元和NKB-IR神经元间杂分布于隔-斜角带(MS-DBB)复合体,两者数量相当。双标神经元在内侧隔核(MS)、斜角带垂直支(vDB)和斜角带水平支(hDB)占Nestin-IR神经元的比例分别为31.5%(27.2%～35.5%)、17.2%(12.9%～22.1%)和23.3%(18.7%～27.4%),占NKB-IR神经元的比例分别为13.1%(9.8%～16.6%)、15.7%(11.2%～20.3%)和32.9%(26.5%～40.1%)。结论成年大鼠基底前脑部分Nestin-IR神经元表达NKB。     

菟丝子含药血清对大鼠胚胎肢芽形态发育的影响

目的探讨不同剂量菟丝子含药血清对SD大鼠胚胎肢芽形态发育的影响。方法采用中药血清药理学方法制备菟丝子含药血清。取孕第15天胚胎前肢芽,随机分为3个实验组、阴性对照组和阳性对照组。实验组和阴性对照组分别加入10%培养体积的高、中、低剂量菟丝子含药血清和正常血清,阳性对照组加入全反式维甲酸溶液(10 mg/mL)。采用体外肢芽悬浮培养法培养72h后收获肢芽,石蜡包埋、切片、HE染色观察肢芽细胞和软骨形态。每组取30个肢芽,测量肢芽长度。结果经HE染色后,菟丝子含药血清低、中剂量组和阴性对照组肢芽结构完整,细胞排列整齐,软骨轮廓清晰,指突明显。高剂量组和阳性对照组肢芽软骨出现,轮廓较清晰,但指突不明显。分段测量肢芽长度后,与阴性对照组比较,低和中剂量组前肢芽近端a段长度和远端b段长度无显著性差异(P>0.05)。而阳性对照组和高剂量组的肢芽长度显著小于阴性对照组,与之比较差异显著(P<0.05)。结论高剂量菟丝子含药血清对SD大鼠胚胎前肢芽生长有抑制作用,可显著抑制肢芽指突的生长,存在潜在的胚胎发育毒性。     

Effects of age on glycogen synthase and phosphorylase activities in rat liver

Six exopeptidases present in human diploid fibroblasts were identified by separation on polyacrylamide gel electrophoresis and their activity profiles against 17 dipeptides, two tripeptides and L-leucine-p-nitroanilide determined. No differences in relative activity or in the electrophoretic patterns of any of the six exopeptidases were detected with ageing. Aminoacylarylamidase activity assayed spectrophotometrically showed significantly increased activity in the middle age-group cells as opposed to the enzyme isolated from young and old cells. Heat-inactivation studies using the same substrate suggested the possibility of an increased proportion of heat-labile enzyme in the old cells but interpretation of the data was difficult because of the complex nature of the inactivation curves obtained. Overall, the results tended to refute the hypothesis that age-related changes in the free amino acid pool of human diploid fibroblasts were associated with significant alterations in the activities of cellular exopeptidases.     

The extracellular matrix during neural crest formation and migration in rat embryos

Summary Changes in the distribution of extracellular matrix components have been investigated immunohistochemically during neural crest development in the rat. Inside the ectodermal epithelium basal lamina components are formed resulting in a separation of neurectoderm and epidermal ectoderm. Within the presumptive neural crest area fibronectin, hyaluronan and chondroitin sulphate become apparent. Upon subsequent neural crest migration the basal lamina becomes disrupted. As the neural crest cells take part in mesectoderm formation, fragments of the basal lamina remain attached to their surface, as is demonstrated with antibodies against laminin and collagen type IV. The extracellular matrix is therefore active both in the separation of neuroectoderm from epidermal ectoderm and in mesectoderm formation.     

Development of acetylcholinesterase-positive thalamic and basal forebrain afferents to embryonic rat neocortex

By combining anterograde and retrograde axonal tracing with AChE histochemistry, we demonstrate the sources of AChE-positive afferents to embryonic neocortex, the pathways they use, their time of arrival into cortex, and their initial invasion of the cortical plate. Acetylcholinesterase (AChE) is expressed by two populations of cortical afferents: AChE is permanently present in basal forebrain fibers and has been reported to be transiently localized in axons of the principal sensory thalamic nuclei over the first few postnatal weeks beginning at the middle of the first week. We first detect AChE-positive afferents histochemically in neocortex on embryonic day seventeen (E17) and determine that they arise from the principal sensory thalamic nuclei. AChE histochemistry labels the entire length of developing thalamocortical axons, including their growth cones and branches. These AChE-positive afferents enter the neocortex by the internal capsule and take an intracortical pathway centered on the subplate layer. As soon as these axons are detected, some have already begun to extend AChE-positive collateral branches superficially toward the cortical plate. By E19, a few collaterals have entered the deep part of the cortical plate and by E21 have densely invaded all but its most superficial undifferentiated part. AChE-positive afferents from basal forebrain structues reach the neocortex by three routes: the external capsule, the internal capsule, and the cingulate bundle. Among basal forebrain components, only the substantia innominata and nucleus basalis of Meynert reach the cortex by the internal capsule. Afferents from these two sources reach neocortex on E18, but are a very minor component of the total population of AChE-positive afferents at this age. Afferents from other basal forebrain components do not reach neocortex until several days later. The spatial and temporal patterns of AChE expression in developing thalamocortical axons indicate that it is useful for delineating their innervation of the primary sensory areas of embryonic neocortex, and suggest that AChE may function in axon extension and cortical differentiation.     

Effect of hyperglycaemia on muscle glycogen mobilization during muscle contractions in the rat

Summary In the rat, muscle glycogen is mobilized during the first stage of exercise, despite normoglycaemia. The aim of the present study was to examine if this process could be prevented or reduced by hyperglycaemia. Three experiments were carried out: in the first, rats were forced to run on a treadmill; in the second the gastrocnemius muscle group was made to contract by stimulation of the sciatic nerve and in the third adrenaline was administered subcutaneously. Each group was divided into two subgroups: control and enriched with glucose (hyperglycaemic). It was shown that hyperglycaemia has no effect on running-induced glycogen mobilization in hind-limb muscles of different fibre composition but prevented it totally in diaphragm muscle. Hyperglycaemia also did not affect the glycogen mobilization induced by stimulation of the sciatic nerve. However, it delayed and reduced markedly the glycogenolytic effect of adrenaline. It is concluded that increased glycogenolysis in muscles at the beginning of exercise may be a consequence of a delay in the activation of glucose transporting mechanisms in muscle cells.     

Muscle glycogen repletion and pre-exercise glycogen content: effect of carbohydrate loading in rats previously fed a high fat diet

We have recently reported that rates of muscle glycogen repletion during the early period of recovery were increased by carbohydrate (CHO) loading in rats previously fed a high fat diet. However, the reason for this remained unanswered. The purpose of this study was to examine whether an increase of glycogen utilization due to an elevated pre-exercise glycogen store would enhance rates of glycogen repletion in muscle. Despite an equal degree of glycogen depletion, the rates of glycogen repletion of soleus, red and white gastrocnemius muscles by postexercise administration of glucose (3.0 g · kg^–1 body mass) and citrate (0.5 g · kg^–1 body mass) were faster in the CHO loaded (3 days) rats than in the nonloaded rats, as a result of elevated pre-exercise glycogen content and consequently the greater glycogen utilization. The higher rate of muscle glycogen repletion may in part be explained by increased postexercise glycogen synthase activity.     

The effect of increased respiratory resistance on glycogen and triglyceride levels in the respiratory muscles of the rat

Summary The effect of increased respiratory resistance (stenosis of the trachea) on glycogen and triglyceride levels in the diaphragm (D) and intercostal (external-IE, internal-II) muscles was studied in the rat. Tracheal stenosis resulted in a reduction of glycogen level in the muscles. For the fed rats the reductions were: D-45 and 79%, IE-14 and 30%, II-14 and 35%, 0.5 and 3 h after stenosis, respectively. For rats fasted for 24 h the reductions were: D-64 and 86%, IE-33 and 71%, II-40 and 82%, after 0.5 and 3 h respectively. The level of triglycerides in the muscles was stable during stenosis in the fed group, whereas in the fasted group it were reduced in the diaphragm by 50% after 0.5 h, and by 52% after 3 h. It is concluded that both endogenous and blood-born energy fuels are utilized by the respiratory muscles during increased resistance breathing. The work was supported by Polish Academy of Sciences (10.4.)