LIPID DEFICIENCY IN THE CENTRAL NERVOUS SYSTEM OF LANDRACE PIGLETS AFFECTED WITH CONGENITAL TREMOR AIII, A FORM OF CEREBROSPINAL HYPOMYELINOGENESIS

—Congenital tremor, type AIII, is characterized by partial agenesis of the white matter of the CNS affecting mainly the spinal cord. The percentage water content of the fresh cord is consistently higher than normal and other parts of the CNS are sporadically affected. The total lipid content (mg/g fresh tissue) is markedly decreased in the cord but brain stem and cerebellum are less severely deficient; the cerebrum is barely deficient. Total amounts of cholesterol, cerebroside and phospholipid (mmol/part) are significantly reduced predominantly in cerebellum, brain stem and cord. Total DNA and protein contents are decreased to a significant extent only in spinal cord. Broadly similar lipid changes are found in fixed tissues. The data are consistent with sub-normal myelination, associated with a deficiency of oligodendrocytes.     

NEUROCHEMISTRY OF THE SPINAL CORD IN CONGENITAL TREMOR OF PIGLETS (TYPE AII), A SPINAL DYSMYELTMOGENESIS OF INFECTIOUS ORIGIN

Abstract— In piglets affected with congenital tremor type AII the CNS was not morphologically underdeveloped; spinal cord weight, total DNA content and fat-free dry matter differed little from control values. However the total lipid extractable from affected spinal cords was only about 63% of values established for normal newborn piglets. In particular, the cerebroside content (a myelin-specific lipid) was reduced to about 30% of the 'normal' value. This was parallelled by the results of an in vitro assay of cerebroside synthesis from [³H]galactose which indicated a metabolic impairment. The altered fatty acid profile of isolatcd cerebrosides further suggested a derangement of fatty acid synthesis. Unlike the spinal cords of normal newborn piglets, tissues from affected piglets contained significant amounts of cholesterol esters carrying the characteristic fatty acids associated with demyelination. This implied that the reduced quantities of possibly abnormal myelin were unstable. Abnormal swollen oligodendrocytes were commonly present in the spinal cords of affected piglets and this was consistcnt with the observed impairment of myelin formation.     

NEUROCHEMISTRY OF THE SPINAL CORD IN EXPERIMENTAL BORDER DISEASE (HYPOMYELINOGENESIS CONGENITA) OF LAMBS

Abstract— The total lipid, cholesterol (free and esterified), cerebroside, phospholipid and fat-free dry matter contents were estimated in spinal cords of lambs affected with experimentally produced Border Disease. Comparisons were made with a healthy control group and with a group of lambs obtained from vaccinated ewes.
Clinically affected lambs showing tremors ('shaking'), a'hairy'birthcoat or both were found to possess one or two myelin lipid abnormalities. These were a generalised deficiency of myelin lipids (notably cerebroside) and the presence of abnormal quantities of esterified cholesterol. The former was particularly associated with the birthcoat defect and the latter with the neurological signs.
Previous exposure of the ewes to the infective agent (vaccination 28 days before mating) appeared to give considerable protection against the degenerative lipid changes and against 'shaking'but less against myelin dysgenesis and'hairiness'.     

大白鼠脊髓、脑干和海马乙酰胆碱酯酶活性的研究

采用乙酰胆碱酯酶 (ACh E)组织化学方法 ,观察了大白鼠脊髓、脑干和海马等脑区 ACh E阳性神经元的活性。结果显示 :(1)脊髓 :脊髓前角、后角神经元 ACh E均为中等阳性 ( ) ,脊髓中间外侧核 ACh E呈强阳性 ( )。 (2 )脑干 :延髓中的三叉神经脊束核、舌下神经核 ACh E均呈强阳性 ( ) ,中缝大核 ACh E呈中等阳性 ( ) ;脑桥的蓝斑核 ACh E呈强阳性 ( ) ,而三叉神经中脑核等核团 ACh E呈中等阳性 ( ) ;中脑的非脑神经核团红核、黑质 ACh E呈阳性 (+ )或中等阳性 ( ) ,脑神经核团动眼神经核和动眼神经副交感核 ACh E呈强阳性 ( )。 (3)海马 :海马 CA3区 ACh E为强阳性( ) ,CA2 和 CA1 区为中等阳性 ( )。本实验表明 ACh E阳性神经元广泛分布于中枢神经系统不同脑区 ,为进一步探讨 ACh在中枢神经系统中的作用提供了形态学资料。     

A NEUROCHEMICAL STUDY OF FIELD CASES OF THE DELAYED SPINAL FORM OF SWAYBACK (ENZOOTICATAXIA) IN LAMBS

Abstract— Spinal cords of 5-8 week-old lambs affected with the delayed or spinal form of swayback were deficient in myelin lipid components such as cholesterol, cerebrosides and phospholipids and contained less water than cords obtained from clinically and histologically unaffected lambs. The rate of synthesis in vitro of cerebrosides containing hydroxy fatty acids was reduced but the fatty acid composition of this and of the "non-hydroxy cerebroside' fractions were quite normal. Isolated myelin was deficient in copper compared with healthy controls and there was a deficiency in one of its basic protein constituents. This suggested an inherent instability of myelin in affected lambs while the presence of some 4 per cent of cholesterol in the esterified form (none normally present) was indicative of degenerative changes. Five out of eight clinically unaffected lambs obtained from the same flocks proved to be sub-clinical cases when the spinal cord was examined histologically and showed some of the neurochemical abnormalities of the overt clinical disease. When affected lambs were kept at the laboratory until 16 weeks old and fed a copper sufficient diet some of the spinal lesions showed signs of regression and there were fewer neurochemical abnormalities. In particular, cholesterol esters could not be detected in the spinal cord lipids.     

THE DISTRIBUTION OF GLYCINE, GABA, GLUTAMATE AND ASPARTATE IN RABBIT SPINAL CORD, CEREBELLUM AND HIPPOCAMPUS

The distribution of glycine, GABA, glutamate and aspartate was measured among about 60 subdivisions of rabbit spinal cord, and among the discrete layers of cerebellum, hippocampus and area dentata. A more detailed mapping for GABA was made within the tip of the dorsal horn of the spinal cord. Spinal ventral horn and dorsal root ganglion cell bodies were analyzed for the amino acids and for total lipid. The distribution of lipid and lipid-free dry weight per unit volume was also determined in spinal cord. Calculated on the basis of tissue water, glycine in the cord is highest in lateral and ventral white matter immediately adjacent to the ventral grey. The distribution of GABA is almost the inverse of that of glycine with highest level in the tip of dorsal horn. It is most highly concentrated in the central 75% of Rexed layers III and IV. Aspartate in the tip of ventral horn is 4-fold higher than in the tip of the dorsal horn and 3 times the average concentration in brain. Glutamate was much more evenly distributed and is relatively low in concentration with slightly higher levels in dorsal than in ventral grey matter. Large cell bodies in both ventral horn and dorsal root ganglion contained high levels of glycine. As reported by others, GABA was found to be high in cerebellar grey layers, area dentata, and regio inferior of hippocampus. Glycine was moderately high in cerebellar layers but moderate to low in hippocampus and area dentata.     

两种亨廷顿蛋白相关蛋白1异构体—HAP1A和HAP1B在大鼠脊髓灰质内的分布特征

目的明确2种亨廷顿蛋白相关蛋白1(huntingtin-associated protein 1,HAP1)异构体—HAP1A和HAP1B在大鼠脊髓灰质内的分布特征。方法提取重组表达的谷胱甘肽S-转移酶(GST)-HAP1AC末端融合蛋白和GST-HAP1BC末端融合蛋白,免疫兔和豚鼠制备分别抗HAP1A和HAP1B特异性多克隆抗体,并采用免疫印迹技术对其特异性和效价进行鉴定和检测;用免疫组织化学技术检测HAP1A和HAP1B在大鼠脊髓灰质内的分布和定位特征。结果成功制备了分别特异性识别HAP1A和HAP1B的高效价多克隆抗体,应用这些抗体进行的免疫组织化学ABC法检测显示,HAP1A与HAP1B在大鼠脊髓灰质内的分布区域相似,二者均在大鼠脊髓灰质RexedⅠ-Ⅹ层表达,在RexedⅠ、Ⅱ层表达最强,中央管周围灰质(RexedX层)其次,在RexedⅢ-Ⅵ层表达水平较低,在脊髓前角(RexedⅦ-Ⅸ层)只有极微弱的或无阳性表达。HAP1A免疫反应产物主要定位在Stigmoid小体,在神经元胞质和近端突起内只有极少的弥散反应产物;HAP1B免疫反应性较强,其免疫反应产物弥散、均匀分布在神经元核周质和近端突起内,也定位在Stigmoid小体上。免疫荧光双重标记显示,约有80%的Stigmoid小体既表达HAP1A也表达HAP1B,其余的Stigmoid小体仅表达HAP1A。结论 HAP1A和HAP1B蛋白在大鼠脊髓灰质内具有相同的区域分布模式,但在神经元内的定位具有明显区别,提示二者可能具有不同的功能。     

大鼠脊髓内甲啡肽、亮啡肽和甲七肽在镇痛和电针镇痛中的不同作用

1.给大鼠脊髓蛛网膜下腔注射甲啡肽200—800nmol引起与剂量相关的镇痛效应。注射脑啡肽降解酶抑制剂Thiorphan 50nmol或Benatin 300nmol可加强电针镇痛,注射甲啡肽抗体则可对抗电针镇痛。这些资料说明内源性甲啡肽确实在痛觉调制系统中起着重要作用。 2.脊髓蛛网膜下腔注射亮啡肽800nmol使痛阈升高44％,其镇痛效应尚不及200nmol甲啡肽的作用(痛闻升高61％);注射甲七肽10-200nmol未见痛阈明显改变。注射亮啡肽或甲七肽抗体并不能对抗电针镇痛;注射甲七肽降解酶抑制剂Captopril 1000nmol也不能加强电针镇痛。这些资料说明,脊髓中的亮啡肽和甲七肽存痛觉调制中可能不起重要作用。     

HIGH AFFINITY UPTAKE OF TRANSMITTERS: STUDIES ON THE UPTAKE OF l-ASPARTATE, GABA, l-GLUTAMATE AND GLYCINE IN CAT SPINAL CORD

Abstract— The uptake of l -aspartate, l -glutamate and glycine each appeared to be mediated by two kinetically distinct systems with apparent K_m's of the order of 10 ('high affinity') and 100 μM ('low affinity') in slices of cat spinal cord, whereas the uptake of GABA appeared to be mediated by a single system of high affinity. The high affinity uptake of these amino acids in slices of spinal grey matter was approximately 5 times faster than that in slices of spinal white matter. The high affinity uptake systems in the cord slices survived homogenisation of the tissue under conditions known to preserve nerve terminals. Subcellular fractionation studies indicated that osmotically-sensitive particles of equilibrium density equivalent to that of 1.0 m -sucrose were at least in part responsible for the uptake of these amino acids. Inhibition studies indicated that three structurally specific systems of high affinity transported these amino acids:

• 1 specific for glycine—not inhibited by GABA or any of the other depressant amino acids found in cat spinal cord;
• 2 specific for GABA—not inhibited by glycine, taurine, l -aspartate or l -glutamate and (3) specific for l -aspartate and l -glutamate—not inhibited by glycine or GABA but strongly inhibited by various acidic amino acids such as l -cysteate and l -cysteine sulphinate.

The high affinity uptake of these amino acids was not inhibited by any of the known antagonists of the postsynaptic actions of these amino acids—strychnine (glycine), bicuculline and benzyl penicillin (GABA), methioninesulphoximine and l -glutamate diethyl ester (l -aspartate and l -glutamate). p-Chloromercuriphenylsulphonate strongly inhibited the high affinity uptake of glycine and GABA but was much less effective as an inhibitor of l -aspartate/l -glutamate high affinity uptake. This is in good agreement with microelectrophoretic studies in which this mercurial was found to potentiate depression of neuronal firing induced by glycine and GABA much more readily than excitation induced by l -aspartate or l -glutamate. These findings suggest the importance of high affinity transport processes in the removal of amino acids from the synaptic environment.     

大鼠脊髓内甲啡肽、强啡肽A-(1—13)和吗啡在镇痛中的相互加强作用

1.大景以辐射热甩尾法测痛。应用脊髓蛛网膜下腔,连续累加注射法观察药物的镇痛作用。脊髓蛛网膜下腔单独注射甲啡肽100nmol不能提高痛阈,但与吗啡或强啡肽A-(1—13)合用时,可明显加强后者的镇痛作用。 2.脊髓蛛网膜下腔单独注射强啡肽A-(—13)2.5nmol本身无镇痛作用,但与吗啡合用时,却能明显加强吗啡的镇痛作用。 3.本文对连续累加注射法的特点及三类阿片受体及其配基对痛觉的调制作用,进行了讨论。