The influence of ketamine and other intravenous anaesthetic agents on cerebral blood flow in the sheep

Cerebral blood flow (CBF) was measured in sheep by measuring clearance of directly injected ¹³³ Xenon from the cerebral cortex. The influence of ketamine at various dose levels on the CBF was measured and compared to the effects produced by pentobarbitone and CT1341. It was found that ketamine caused an initial depression of CBF followed by a rise, pentobarbitone produced a profound long lasting depression whilst CT1341 caused an initial depression which was rapidly followed by a return to control values.     

Quantitative in vivo measurement of central benzodiazepine receptors in the brain of cats by use of positron-emission tomography and [11C]flumazenil

OBJECTIVE: To map central benzodiazepine receptors (BZRs) in the brain of cats by use of positron-emission tomography (PET) and [11C]flumazenil. ANIMALS: 6 male cats that weighed between 2.0 and 3.6 kg. PROCEDURE: Brain images obtained by PET evaluation of [11C]flumazenil were superimposed on T2-weighted magnetic-resonance imaging (MRI) scans of the same cats. Detailed anatomic regions, such as the cerebral cortex, striatum, thalamus, midbrain, and cerebellum, on the PET images were evident by PET-MRI registration. Regional binding of [11C]flumazenil to BZRs was quantitatively measured by use of a model with 2 tissue compartments and 4 variables. RESULTS: The highest value for distribution volume was observed in the cerebral cortex, and the lowest value was found in the midbrain of cats. CONCLUSIONS AND CLINICAL RELEVANCE: Binding of [11C]flumazenil to BZRs in the brain of cats can be quantitatively measured by use of PET with the aid of PET-MRI registration. It is difficult to diagnose changes in these neuroreceptors within the field of current veterinary science. In the future, PET should prove useful for investigating and diagnosing brain disorders in animals in clinical settings.     

Choline acetyltransferase activity in rodent brain: A comparative study in the rat,mouse and guinea pig

The choline acetyltransferase (ChAT; EC 2.3.1.6) activity in the whole brain and in the cerebral cortex, cerebellum, hypothalamus, hippocampus, amygdala, midbrain, pons and medulla oblongata of adult rat, mouse and guinea pig was measured by the same method. Results show species difference in the ChAT activity of the whole brain and of several specific brain areas in these animals. ChAT activity was, however, consistently lowest in the cerebellum of these rodent species.     

Effects of pentobarbitone anaesthesia and atropine on the intravenous glucose tolerance test in normal dogs

The effect of atropine (0·1 mg/kg b.w. s.c.) and of pentobarbitone anaesthesia (25 mg/kg b.w.) on the plasma glucose clearance and insulin response to an intravenous load of 600 mg and 1,250 mg/kg b.w. glucose was studied in twenty-four normal young Dalmatian dogs (ten male, fourteen female). Neither the rate of disappearance of glucose from the circulation, nor the insulin release following both glucose loads was altered by atropine. However, the disposal of intravenous glucose was significantly (P < 0·01) delayed and the insulin release significantly decreased under pentobarbitone anaesthesia. It is suggested that a decreased blood flow through the pancreas during pentobarbitone anaesthesia is most likely the cause of the decreased insulin release which in turn causes a delayed rate of disappearance of glucose from the circulation. It is therefore concluded that an intravenous glucose tolerance test, as diagnostic procedure, should never be done in anaesthetized dogs.     

A morphological and stereological study on brain,cerebral hemispheres and cerebellum of New Zealand rabbits

The aim of this research was to determine brain, cerebral hemispheres and cerebellum volume and volume ratios by using stereological methods and investigate morphological differences between female and male New Zealand rabbits. The study was applied on 14-month old (10 male and 10 female) New Zealand rabbits. The materials removed from the cavum cranii using dorsal approach. After following routine histological procedure, paraffin blocks were prepared and cut every seventieth section at 10 μm thickness. Slides were stained with Crossmon's triple stain and photographed. The sectional images obtained were transferred to ImageJ program to estimate grey and white matter volume on cerebral hemispheres and cerebellum with principle of Cavalieri. According to results, there was no asymmetry on the left and right cerebral hemispheres of New Zealand rabbits. In the total hemisphere volume calculated by Cavalieri principle, grey and white matter ratio was 81.57% and 18.43% in female, 82.80% and 17.20% in male. It was found that the white matter was significantly higher in females than males in cerebral hemispheres (p < .05). Also, it was found that grey and white matter ratio in total cerebellum volume was 67.82% and 32.18% in female, 67.94% and 32.06% in male respectively. It was determined that the females' white matter was larger than male rabbits in cerebellum (p < .05). It is thought that morphometric data obtained from this study will contribute to the existing anatomical knowledge and also considered as reference values in the clinical sciences.     

The activity and properties of adenosine triphosphatase in various swine organs (liver, cerebral and kidney cortex, small intestinal mucosa)]

Studies into the activity of adenosine triphosphatase (ATPase) in homogenates of liver, cerebral cortex, renal cortex, and mucosa of small intestine of swine have shown differentiated activity patterns, with peak activity developing in the liver. This has been related to a particularly high metabolism performance of the liver in fattening pigs. No difference was found to exist between magnesium activation of ATPase of swine tissue homogenates and that in tissue obtained from ruminants. ATPase which could be activated by sodium and potassium ions and inhibited by ouabain was detectable from cerebral and renal cortex. Sodium and potassium ATPases accounts from some 25 per cent of the total activity. ATPase that could be stimulated by calcium ions was recorded only from liver homogenate. The optimum pH values of ATPase were between 7.5 and 8 in the liver, 9 in mucosa of small intestine, and 9.5 in cerebral and renal cortex.     

慢性镉暴露对小鼠大脑皮质的毒性损伤作用

为探究慢性镉暴露对小鼠大脑皮质的毒性损伤作用,选取雌性BALB/c小鼠用0(对照组)、5和25 mg/L不同浓度氯化镉自由饮水染毒16个月建立慢性镉中毒模型,试验结束后剖检采集小鼠完整脑组织,测定脑系数;光学显微镜和透射电子显微镜观察大脑皮质病理组织学和超微结构变化;比色法检测大脑皮质中总超氧化物歧化酶(T-SOD)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-P_X)的活性和还原型谷胱甘肽(GSH)、丙二醛(MDA)的含量。结果显示:与对照组相比,镉处理组脑系数均显著降低(P<0.05);镉处理组大脑皮质细胞核深染、固缩,呈三角形或不规则形,线粒体嵴断裂、溶解,部分呈空泡变性;镉处理组大脑皮质中T-SOD活力极显著下降(P<0.01),CAT活力显著下降(P<0.05),MDA、GSH含量极显著升高(P<0.01),5 mg/L氯化镉组GSH-PX活力显著升高(P<0.05),25 mg/L氯化镉组GSH-PX活力极显著升高(P<0.01)。提示:慢性镉暴露可影响小鼠脑发育,引起小鼠大脑皮质病理损伤、超微结构损伤和氧化损伤。     

Regulation of tissue beta-adrenergic, glucocorticoid and androgen receptors induced by repeated exposure to growth promoters in male veal calves

Biochemical modifications induced by a combination of anabolic compounds in target organs of male veal calves have been evaluated. Six male Friesian crossbred calves were treated with of 17beta-estradiol, dexamethasone sodium phosphate and clenbuterol or served as controls. beta-Adrenoceptors (beta-ARs) were measured in myocardium, lung, spleen, cerebral cortex, hippocampus, thalamus, hypothalamus, and hypophysis, glucocorticoid receptors (GRs) in the spleen and androgen receptors (AnRs) in the testis, by binding assay. A significant decrease in beta-ARs was observed in all tissue samples from treated animals. In the spleen the two GR subtypes found, low (LA) and high (HA) affinity GRs, were down-regulated by the treatment. A significant (P<0.05) decrease of testis weight and a significant (P<0.05) up-regulation of AnRs was also observed. Our data demonstrate that long-term treatment with anabolic compounds markedly affects receptor concentrations in target organs of male veal calves. Thus, studies investigating biological assays as screening methods to detect such compounds should be encouraged.     

The effect of thrombin on astrocyte stellation with regional specificity

In this study, we have examined the possible existence of astrocyte regional heterogeneity in thrombin effect on astrocyte stellation. Neonatal astrocytes were cultured for 2 weeks from six different regions of the neonatal rat brain, including the cerebral cortex, hippocampus, brainstem, midbrain, hypothalamus and cerebellum. Culture medium was changed to DMEM containing 8-CPT-cyclic AMP (cAMP) or isoproterenol plus various concentrations of thrombin for 2 hr. Thrombin effectively blocked both cAMP- and isoproterenol-induced cell stellation in a dose-dependent manner in all regional astrocytes except cerebellar astrocytes. RT-PCR analysis showed that thrombin receptor mRNA was expressed in all regional astrocytes, suggesting that cerebellar astrocytes may maintain a unique signaling pathway downstream of the thrombin receptor.     

Lafora's disease in an epileptic Basset hound

A 6-year-old Basset hound developed a progressive central nervous system disease culminating in epileptic seizures. Histologically, Lafora bodies were found in neurones of the middle and deeper cerebral cortex and midbrain, in Purkinje cells and their processes, and in glial cells of the molecular layer of the cerebellum. Many were also observed free in the neuropil. The ultrastructural and histochemical characteristics of the bodies were similar to those described in previous human and canine cases of Lafora's disease.     

Transthyretin amyloidosis and two other aging-related amyloidoses in an aged vervet monkey

An aged male vervet monkey showed severe cardiac arrhythmia for more than 3 years. A multifocal amyloid consisting of transthyretin was deposited in all areas of the heart wall, especially in the extracellular stroma among muscle fibers and external tunica of arterioles. Moreover, the amyloid was deposited in the stroma and arterioles of other systemic organs except the liver and spleen. These characteristics are consistent with senile systemic amyloidosis in humans. A second amyloid consisting of amyloid beta protein was in senile plaques and cerebral amyloid angiopathy in the cerebral cortex. A third amyloid consisting of islet amyloid polypeptide was deposited in islets of the pancreas. Apolipoprotein E and amyloid P component colocalized with the 3 amyloids. Thus, 3 different aging-related amyloids were found in an aged vervet monkey. In particular, to our knowledge, this is the first report on spontaneous transthyretin amyloidosis in animals.     

Lafora's disease in an epileptic Basset hound

A 6-year-old Basset hound developed a progressive central nervous system disease culminating in epileptic seizures. Histologically, Lafora bodies were found in neurones of the middle and deeper cerebral cortex and midbrain, in Purkinje cells and their processes, and in glial cells of the molecular layer of the cerebellum. Many were also observed free in the neuropil. The ultrastructural and histochemical characteristics of the bodies were similar to those described in previous human and canine cases of Lafora's disease.     

Early milk availability modulates the activity of choline acetyltransferase in the cerebral cortex of rats

The purpose of the present study was to investigate the effect of milk in the early stage of lactation on the maturation of cholinergic neurons in the cerebral cortex of rats. Pups were removed from their mothers immediately following parturition and placed with foster dams at days 5–7 of lactation. At days 18 and 56 after birth, the activity of choline acetyltransferase (ChAT), an enzyme responsible for acetylcholine synthesis, in different areas of the cerebral cortex was examined by high‐performance liquid chromatography electrochemical detection. In the frontal and hindlimb/parietal regions of the cerebral cortex, the lack of early milk significantly decreased ChAT activity at days 18 and 56. There was no effect on gains in the body or brain weight of infants. ChAT activity in the occipital area tended to be lower in the early milk‐deprived rats. The intake of early milk potentially contributes not only to nutrients for the growth of newborn infants, but also to the functional maturation of the cholinergic neurotransmission system in a region‐specific manner.     

An epizootic of cerebrospinal nematodiasis in cottontail rabbits.

A progressively debilitating neurologic syndrome characterized by torticollis, ataxia, circling, and abnormal posture was observed in 16 of approximately 60 cottontail rabbits (Sylvilagus floridanus) captured in a 12-hectare portion of a woodlot in southwestern Virginia. Inflammatory and degenerative alterations in cerebellum and midbrain regions were characterized principally by malacia, perivascular cuffing, and gliosis. Single Ascaris columnaris larvae were found in the cerebellum of 2 rabbits and the spinal cord of 1 rabbit.     

Complementary distributions of amyloid-beta and neprilysin in the brains of dogs and cats

Neprilysin is an amyloid-beta-degrading enzyme localized in the brain parenchyma. The involvement of neprilysin in the pathogenesis of Alzheimer's disease has recently received much attention. We examined the localization of neprilysin and amyloid-beta, as well as the activity of neprilysin, in the brains of dogs and cats of various ages to clarify the relationship between neprilysin activity and amyloid-beta deposition. The distribution of neprilysin was almost identical in dogs and cats, being high in the striatum, globus pallidus, and substantia nigra, but very low in the cerebral cortex. The white matter and hippocampus were negative. Neprilysin activity in the brain regions in dogs and cats was ranked from high to low as follows: thalamus/striatum > cerebral cortex > hippocampus > white matter. Amyloid-beta deposition was first detected at 7 and 10 years of age in dogs and cats, respectively, and both the quantity and frequency of deposition increased with age. In both species, amyloid-beta deposition appeared in the cerebral cortex and the hippocampus. In summary, the localization of neprilysin and neprilysin activity, and that of amyloid-beta, were complementary in the brains of dogs and cats.     

赛拉唑对大鼠不同脑区NO-NOS-cGMP信号转导系统的影响

观察赛拉唑对大鼠不同脑区NOS活性、NO和cGMP含量的影响,以探讨NO-NOS-cGMP信号转导系统对赛拉唑全麻分子机理的调控.Wistar纯种大鼠84只,随机选取12只为生理盐水对照组,其余随机均分为低剂量赛拉唑用药组和高剂量赛拉唑用药组,每个剂量组又分为麻醉期、翻正反射恢复期和苏醒期3个亚组(各12只).用分光光度法测定大鼠不同脑区NOS活性和NO产量,放射免疫法测定脑cGMP含量.结果表明,赛拉唑能明显地抑制大鼠大脑皮质、小脑、海马和脑干NOS活性、NO和cGMP含量.并且NOS活性、NO含量的抑制作用呈现荆量依赖性增加趋势,这种变化与大鼠赛拉唑麻醉后行为学变化相吻合.结果提示,NO-NOS-cGMP信号传递系统参与了赛拉唑全麻作用产生的分子学机制的调控.     

Ameliorative effects of oral ginger and/or thyme aqueous extracts on productive and reproductive performance of V‐line male rabbits

The objective of this study was to determine the impact of ginger and/or thyme aqueous extracts administration on the growth rate, caecum activity, reproductive performance and semen quality of rabbits. A total of 24 V‐line male rabbits at the age of 12 weeks were divided randomly into four equal groups (6/each) until 24 weeks of age. Treatments were as follows: drinking fresh water and served as control (G1); drinking water supplemented with 100 mg/kg b. wt. of ginger aqueous extract (G2); drinking water supplemented with 50 mg/kg b. wt. of thyme aqueous extract (G3); drinking water supplemented with 100 mg/kg b. wt. of ginger aqueous extract plus 50 mg/kg b. wt. of thyme aqueous extract (G4). Administration of aqueous thyme extract with 50 mg/kg b. wt. improved (p < 0.001) feed intake and growth performance compared to control. The highest average daily gain (p < 0.001) was found for G3 rabbits followed by G4, G2 and G1 respectively. While the most efficient feed conversion ratio was found in G4. Group 3 and group 4 had significant (p < 0.05) positive effect on caecum pH, ammonia and TVFAs concentration. Data indicated that treated groups had hastened the age with heavier body weight, larger testicular size and higher testosterone level. Also, most semen characteristics (volume, progressive motility, sperm concentration and normal spermatozoa) were higher in treated groups compared with the control group. Furthermore, gathering of the spermatozoa in the lumen of the seminiferous tubules, expanded epithelial cells stature of the epididymis with stuffed lumens with sperms in treated groups. In conclusion, aqueous extracts of ginger and/or thyme can be used as a growth promoter for improving reproductive performance of V‐line male rabbits.     

Cortical laminar necrosis detected by diffusion-weighted imaging in a dog suspected of having hypoglycemic encephalopathy

We describe a 5-year-old castrated male dog suspected hypoglycemic encephalopathy that was evaluated by using diffusion-weighted imaging (DWI). The dog experienced hypoglycemia after prolonged generalized and continued partial seizures. In the acute phase, DWI showed hyperintensity in the left temporal lobe. After about a month, DWI maintained hyperintensity, and left middle cerebral artery dilation was noted on magnetic resonance angiography (MRA). In the chronic phase, the left temporal lobe lesion was replaced by cerebrospinal fluid. In humans, it was reported that cortical laminar necrosis (CLN) with hypoglycemic encephalopathy presents hyperintensity in the cerebral cortex on DWI and increased vascularity of the middle cerebral artery branches on MRA. In conclusion, DWI has detected CLN in a dog suspected hypoglycemic encephalopathy.     

Fas对镉暴露致大鼠大脑皮质自噬体形成的影响

为探究死亡受体Fas在镉暴露致大鼠大脑皮质自噬体形成中的作用,将24只21日龄雄性SD大鼠随机分为4组,分别为对照组、镉组、镉与对照病毒共处理组、镉与Fas基因沉默病毒共处理组。试验期间,对照组大鼠自由饮用纯净水,病毒处理组大鼠于第1天以每只1.4×10¹¹vg的剂量通过尾静脉注射相应病毒,4周后镉染毒组大鼠自由饮用镉水(50 mg·L^-1),持续90 d。试验结束后,透射电镜观察大脑皮质中自噬体数量,Western blot检测大脑皮质细胞外信号调节激酶1/2(Erk1/2)、p-Erk1/2、自噬相关蛋白7(ATG7)、自噬相关基因(Beclin-1)、微管相关蛋白1轻链3(LC3)蛋白表达水平,免疫荧光染色检测LC3表达水平。结果显示,镉暴露增加大脑皮质中自噬体数量,极显著激活Erk1/2并上调ATG7、Beclin-1、LC3蛋白表达水平(P<0.01);Fas基因沉默抑制镉引起的自噬体数量增加,极显著抑制镉致Erk1/2激活及ATG7、Beclin-1、LC3蛋白表达水平升高(P<0.01)。结果表明,Fas通过激活Erk1/2参与镉致大鼠大脑皮质自噬体形成。     

Effects of season and sex on in vitro aromatase and 17β-oxidoreductase activities in the brain and anterior pituitary gland of gonadectomized sheep

To improve understanding of seasonal control of reproduction, we studied effects of season and sex on in vitro conversion of androstenedione to estrone and testosterone within the brain and anterior pituitary gland of recently gonadectomized sheep. For both sexes, aromatase activity was relatively high in the amygdala and hypothalamus plus preoptic area (HPOA), but aromatase was not detected in the parietal cortex or the anterior pituitary gland. Aromatase activity of the amygdala was not affected by sex or season. For castrated rams, aromatase activity in the HPOA in May was <25% of that in December (P<.05). For ovariectomized ewes, however, aromatase activity in the HPOA was similar in May and December (P>.05). All tissues contained 17β-oxidoreductase. For the amygdala and HPOA, conversion of androstenedione to testosterone was greater (P<.05) in the male than the female, regardless of season. In rams, 17β-oxidoreductase activity was lower in the HPOA and higher in the anterior pituitary gland in May than in December. In the anterior pituitary of ewes, however, 17β-oxidoreductase activity was higher in December. Thus, conversion of androstenedione to testosterone and estrogens within the brain and anterior pituitary gland could help to control the secretion of luteinizing hormone. We postulate that in rams a seasonal reduction of aromatase activity in the HPOA and increase in 17β-oxidoreductase in the anterior pituitary gland during May may be involved with onset of the seasonal increase in LH secretion.