EFFECTS OF SURGICAL DECENTRALIZATION AND NERVE GROWTH FACTOR ON THE MATURATION OF ADRENERGIC NEURONS IN A MOUSE SYMPATHETIC GANGLION

Abstract— The increase in tyrosine hydroxylase activity in mouse superior cervical ganglion during postnatal development was prevented by administration of the protein synthesis inhibitor cycloheximide. Surgical section of the preganglionic nerves in 4-day-old mice prevented the normal increases in tyrosine hydroxylase and monoamine oxidase activity in the ganglion during development. Surgical decentralization also prevented the developmental increases in ganglion size and cell numbers. The preganglionic fibres thus appear to exert a general regulatory effect on the growth and biochemical maturation of postganglionic adrenergic neurons in sympathetic ganglia. Administration of nerve growth factor to young mice failed to eliminate the differences in ganglion size, cell numbers and tyrosine hydroxylase activity between normally innervated and decentralized ganglia. Nerve growth factor, however, caused an increase in all these parameters in both control and decentralized ganglia–the magnitude of these increases being greatest in the control ganglia. Administration of carbachol and physostigmine to neonatal mice did not influence the normal development of tyrosine hydroxylase activity in the superior cervical ganglion.     

BIOCHEMICAL AND MORPHOLOGICAL EFFECTS OF TESTOSTERONE TREATMENT ON DEVELOPING SYMPATHETIC NEURONS

Abstract— Neonatal rats were treated with testosterone propionate (TP) or isoproterenol (ISO) to determine whether (1) increases in salivary gland mass are associated with alteration of developing sympathetic neurons and (2) whether effects on neuron growth are secondary to altered target mass itself or to increases in salivary growth factors. TP treatment is known to result in salivary tubule hypertrophy and elevated nerve growth factor (NGF) content whereas IS0 treatment results in acinar hypertrophy and no known alteration in NGF. TP treatment increased submaxillary gland weight as well as tyrosine hydroxylase (T-OH) activity, adrenergic neuron numbers and total protein in the innervating superior cervical ganglion (SCG). Unilateral sialectomy prevented the increase in T-OH activity in the SCG, suggesting that the salivary glands were necessary for this effect. T-OH activity and total protein were elevated in the distant sixth lumbar sympathetic ganglion after TP treatment, suggesting that sympathetic development as a whole was affected and that humoral factors may be involved. Salivary gland weight was also elevated following ISO administration, but T-OH activity in the SCG was not affected. These observations suggest that TP treatment increases T-OH activity and sympathetic neuron numbers by alteration of specific salivary humoral growth factor(s).     

OCCURRENCE AND PROPERTIES OF MONOAMINE OXIDASE IN ADRENERGIC NEURONS

—Monoamine oxidase activity of peripheral organs of various species has been examined after surgical, chemical and immunological sympathectomy to assess the proportion of enzyme activity in adrenergic neurons and in extraneuronal cells. Significant falls in monoamine oxidase activity of vas deferens, submaxillary gland, iris and spleen were seen after sympathetic denervation although not in heart, small intestine and kidney. It was suggested that a correlation exists between the extent of the fall in monoamine oxidase activity after sympathectomy and the density of sympathetic innervation of the control organ. Studies of monoamine oxidase activity in vas deferens after inhibition with clorgyline suggested multiple forms of monoamine oxidase. Differences in inhibitor sensitivity, substrate specificity and thermal inactivation of monoamine oxidase in normal and denervated vas deferens were found and it was suggested that differences exist in the properties of the neuronal and extraneuronal monoamine oxidase.     

OCCURRENCE AND PROPERTIES OF CATECHOL-O-METHYL TRANSFERASE IN ADRENERGIC NEURONS

—A study has been made of the catechol-O-methyl transferase activity of some peripheral tissues after sympathetic denervation. A fall in catechol-O-methyl transferase activity was found in some organs, e.g. rat and rabbit vas deferens, cat nictitating membrane and rabbit submaxillary gland but not in mouse heart and spleen. It was found that suboptimal concentrations of S-adenosylmethionine did not reveal a significant difference between normal and denervated organs but at optimal concentrations a fall was seen in some organs. Catechol-O-methyl transferase activity was present in bovine splenic nerve and in adrenal medulla. It is suggested that the fall in enzyme activity after denervation indicates a neuronal cellular localization. A kinetic study of catechol-O-methyl transferase from normal and denervated rat vas deferens suggested that the neuronal and extraneuronal catechol-O-methyl transferase had different kinetic properties and an estimation of the kinetic constants of the neuronal enzyme was made.     

THE INDUCTION OF BIOCHEMICAL AND MORPHOLOGICAL MUTANTS IN THE MOSS PHYSCOMITRELLA PATENS

Physcomitrella patens is a monoecious, cleistocarpous moss which completes its life cycle under defined conditions in 7 to 8 weeks. Sexual reproduction is readily obtained by culturing gametophytes at 15 to 19 C. Mutants were induced by treatment of either spores or protonemal cells with ethyl methane sulfonate, N-methyl-N'-nitro-N-nitrosoguanidine and X-rays. Thiamine, para-aminobenzoic acid, niacin and yeast extract auxotrophs were obtained. Growth response to various supplements was studied in the auxotrophic mutants. Five yellow mutants and two morphological mutants were induced. The chlorophyll content of the yellow mutants is reduced 35-65% of wild type. The self-sterile, para-aminobenzoic acid-dependent mutant was used as the archegonial parent in crosses with a yellow mutant and a morphological mutant. The self-sterility of the para-aminobenzoic acid-requiring mutant appears to be pleiotropically related to the auxotrophic condition, since self-sterility does not segregate from nutritional dependence in progeny of crosses. On the basis of tests with heterozygous diploids obtained by aposporous regeneration of capsule cells, two mutant alleles were shown to be recessive to their respective wild-type alleles.     

STRUCTURAL AND BIOCHEMICAL MATURATION OF THE CEREBRAL PALLIUM IN RABBIT FETUSES: MORPHOGENESIS AND LIPIDS

Morphological parameters of maturation of the cerebral pallium in rabbit fetuses ranging between 20 days of gestation (d.g.) and the early neonatal stage are expressed semi-quantitatively and correlated with progressive changes in the brain lipids, glycolipids and nucleic acids. Dual expression of the chemical values, using as referents both the dry weight of the tissue and the DNA unit, reveal the crucial stage in brain development when rapid cell proliferation is replaced by rapid cell growth; this stage in rabbit fetuses occurred between 28 and 30 d.g. Between 20 d.g. and the early neonatal phase the RNA decreased moderately when expressed per unit of DNA. Even at the time of term birth the cortical nerve cells of the rabbit showed signs of immaturity including a relatively small nuclear volume. On the dry weight basis, the lipids of the cerebral pallium exhibited little change in composition during fetal development; however, cerebrosides rose substantially between 30 d.g. and the early neonatal phase. When expressed per unit of DNA, all lipids and glycolipids continued to increase progressively in a pattern characteristic of growth throughout the prenatal period studied. This increase was also apparent when the lipid constituents were expressed per total pallium at the progressive gestational stages. The molar ratios of phospholipids:cholesterol:cerebrosides in the pallium of rabbits of different ages were as follows: in adult rabbits-2.9: 2.6: 1.0, in the newborn-2.9: 1.3: 0.2 and in the 30 d.g. fetuses-3.0: 1.2:0.44. These values reflect the fact that during maturation the content of phospholipids changes little, whereas that of cholesterol and especially erebrosides increases markedly.     

黄瓜果实贮藏过程中某些形态,生化变化及其控制

黄瓜果实采后贮藏过程中,随着其花端部位的种子的不断发育,中部及茎端逐渐萎缩变糠,花端膨大(称为“大头现象”)。花端胎座组织中蛋白质、DNA、RNA 及干重等都随着时间延长呈增加趋势,而中部组织的上述物质的含量则急剧下降。贮藏20天,中部果皮及胎座组织中 DNase 活性分别增加了5和7倍,RNase 活性增加了5和6倍,这两种酶活性在花端组织中则几无变化。实验发现用 BA+GA,处理果实对于延迟花端膨大及中部萎缩有效,并能显著延缓果实叶绿素含量的降低。未授粉果实在贮藏过程中不出现“大头现象”,其蛋白质等物质的含量在果实各部位几乎以相同的速度降低。     

MORPHOLOGICAL AND BIOCHEMICAL CHARACTERIZATION OF GOLDFISH ERYTHROPHORES AND THEIR PTERINOSOMES

The fine structure of integumental erythrophores and the intracellular location of pteridine and carotenoid pigments in adult goldfish, Carassius auratus, were studied by means of cytochemistry, paper and thin-layer chromatography, ionophoresis, density-gradient centrifugal fractionation, and electron microscopy. The ultrastructure of erythrophores is characterized by large numbers of somewhat ellipsoidal pigment granules and a well-developed system of tubules which resembles endoplasmic reticulum. The combined morphological and biochemical approaches show that pteridine pigments of erythrophores are located characteristically in pigment granules and are the primary yellow pigments of these organelles. Accordingly, this organelle is considered to be the "pterinosome" which was originally found in swordtail erythrophores. Major pteridines obtainable from goldfish pterinosomes are sepiapterin, 7-hydroxybiopterin, isoxanthopterin, and 6-carboxyisoxanthopterin. Density-gradient fractions indicate that carotenoids are mostly associated with the endoplasmic reticulum. Both tyrosinase and possibly a tyrosinase inhibitor containing sulfhydryl groups are present in the pterinosome. The possible existence of a tyrosinase inhibitor is suggested by the marked increase of tyrosinase activity upon the addition of iodoacetamide or p-chloromercuribenzoic acid. In the light of their fine structure, pigmentary composition, and enzymatic properties, the erythrophores and pterinosomes are discussed with respect to their probable functions and their relationship to melanophores.     

THE PRODUCTION AND INHIBITION OF ACTION CURRENTS BY ALCOHOL

Suitable concentrations of ethyl alcohol (1 to 1.5 M) applied to a spot on a cell of Nitella lower the P.D. enough to cause action currents. The alcohol then suppresses action currents arriving from other parts of the cell and acts as a block. After the alcohol is removed the normal P.D. and irritability return. Similar experiments on the sciatic nerve and skin of the frog produced only a negative result.     

大鼠颈上神经节烟碱电流的整流及失敏

在培养的新生大鼠颈上神经节交感神经元标本上,用全细胞膜片钳技术研究了烟碱型乙酰胆碱受体（ｎＡＣｈＲ）通道的整流及失敏现象。烟碱激动剂引起的全细胞电流在膜电位为负值时随膜电位呈线性改变,而在膜电位达＋６０ｍＶ时仍不出现外向电流,表现出强烈的内向整流。ｎＡＣｈＲ通道电流存在失敏现象,即持续恒压喷射激动剂所引起的全细胞电流随时间呈指数衰减,不能保持在峰值水平,失敏随激剂浓度呈量效关系,膜电位的超极化也加     

INHIBITION OF DIHYDROFOLATE REDUCTASE BY PALMITOYL-CoA AND THE REVERSAL OF THE INHIBITION BY SPERMINE AND SPERMIDINE IN THE EGGS OF THE SEA URCHIN,HEMICENTROTUS PULCHERRIMUS*

Dihydrofolate reductase activity in fertilized eggs of the sea urchin, Hemicentrotus pulcherrimus, was almost the same as in unfertilized eggs. Aminopterin inhibited the enzyme competitively with dihydrofolate (FH₂). The apparent K_m value for FH₂ in the dihydrofolate reductase reaction was about 0.1 μM in the crude homogenate of both unfertilized and fertilized eggs. Dihydrofolate reductase in the eggs was also inhibited by palmitoyl-CoA. The inhibition was canceled by polyamines, especially by spermine, but putrescine failed to prevent the enzyme from the inhibition. The change in long-chain acyl-CoA and polyamine concentrations during fertilization are discussed as possible regulatory factors of the enzyme.     

SELECTIVE INHIBITION BY APHIDICOLIN OF THE ACTIVITY OF DNA POLYMERASE ALPHA LEADS TO BLOCKADE OF DNA SYNTHESIS AND CELL DIVISION IN SEA URCHIN EMBRYOS

Aphidicolin at 2 μg/ml caused 90% inhibition of mitotic cell division of sea urchin embryos at the I-cell stage. However, at 40 μg/ml it did not affect meiotic maturational divisions of starfish oocytes, which do not involve DNA replication. At 2 μg/ml it caused 90% inhibition of incorporation of tritiated thymidine into DNA of sea urchin embryos but did not affect protein or RNA synthesis even at a higher concentration. At 2 μg/ml it also caused 90% inhibition of the activity of DNA polymerase α, obtained from the nuclear fraction of sea urchin embryos, but did not affect the activity of DNA polymerase β or γ. These findings suggest that DNA polymerase α is responsible for replication of DNA in sea urchin embryos.     

代谢型谷氨酸受体5与白细胞介素1受体Ⅰ型在大鼠大脑皮质及海马神经元的共存

目的 研究代谢型谷氨酸受体5(mGluR5)和白细胞介素1受体I型(IL-1RI)在大鼠大脑皮质和海马的分布及共存状况。方法 采用相邻切片的免疫细胞化学双标法,在两张相邻脑冠状切片上分别显示mGluR5与IL-1RI的免疫组化染色结果,通过显微摄像确定mGluR5／IL-1RI双标神经元。结果 切片上mGluR5阳性产物为蓝黑色,定位于细胞膜上;IL-1RI阳性产物为棕黄色,主要定位于细胞膜,也存在于神经元内。在大鼠大脑皮质及海马锥体细胞层均存在较丰富的mGluR5及IL-1RI阳性神经元。在大脑皮质,有部分神经元内mGluR5与IL-1RI共存;在海马锥体细胞层,mGluR5及n1RI阳性反应细胞密集,分布区重叠,很可能也存在二共存的神经元。结论 大鼠大脑皮质内存在mGluR5及IL-1RI共存神经元。本研究的结果为免疫神经调质在神经元内相互作用提供了形态学依据。     

THE MORPHOLOGICAL EFFECTS OF PROTEIN SYNTHESIS INHIBITION IN MARSILEA

Marsilea vestita and M. drummondii were grown in sterile cultures to which concentrations of the protein synthesis inhibitors, 2-thiouracil (10 mg/liter) and 5-fluorouracil (1 mg/liter) had been added. When young sporelings are grown in a solution of thiouracil at optimum concentration, there is an inhibition of the rate of leaf formation, a retardation of the leaf heteroblastic series, and all leaves develop as land forms. When thiouracil is added to plants which are already producing typical adult, quadrifid leaves, the effects depend on whether the treated plants are water or land forms. Plants which are typically water forms convert to land forms. After treatment successive leaves develop typical sunken stomata on both leaf surfaces. The tissues of the rhizome, root and petiole are more compact and, in general, the cells of the plant have thicker walls. Vascular patterns are not changed, though the size of the rhizome, root and petiole may be reduced. Plants which are typically land forms are less affected than the water forms, but they show a small reduction in apex volume and an apparent reversion of the leaflet number from the typical quadrifid leaf to a trifid, bifid, or single lamina condition. In both land and water forms apical dominance may be broken by treatment with 10 mg/liter thiouracil or 1 mg/liter fluorouracil and numerous lateral branches develop. Higher concentrations (15–25 mg/liter of thiouracil) may result in abnormal development of lateral axillary buds, petiole bases and leaflets. The meristems of the plant are differentially sensitive to thiouracil; leaflet meristems are most sensitive, the root meristems are the least sensitive. It appears that a true reversion to juvenile leaf development need not occur even though protein synthesis and the volume of the apex are reduced. The development of the land or water form in Marsilea appears to depend on rate of growth. Hence inhibition of the growth of typical water forms, through inhibition of protein synthesis, causes a shift in development toward the morphology typical of land forms.     

AN INTEGRATED MORPHOLOGICAL AND BIOCHEMICAL STUDY OF A PURIFIED PREPARATION OF THE SUCCINATE AND DPNH OXIDASE SYSTEM

Electron micrographs of a purified succinate and DPNH oxidase system prepared from heart muscle reveal that it has a vesicular appearance and is membranous in nature. In keeping with its vesicular appearance is the fact that light scattering by this preparation shows marked changes as the molarity of the suspending medium is altered. Treatment of this preparation with 0.5 per cent deoxycholate solutions removes a large part of the lipide material, which comprises almost half of the dry weight of the preparation. The residue, which still contains the "core" of the cytochrome electron transmitter system, as shown by spectroscopic and enzymatic experiments, is still structured and is membranous in morphological appearance. It is concluded that the enzyme preparation is largely composed of fragmented mitochondrial membranes, and some of the consequences of the localization of the succinate and DPNH oxidase systems in or on these membranes are discussed.     

多巴胺对大鼠背角WDR神经元的抑制不被酚妥拉明和纳洛酮所拮抗

本实验用微电极细胞外记录方法研究了脊髓局部应用多巴胺对大鼠背角WDR神经元的抑制作用。实验在43只SD大鼠上共记录到54个WDR神经元。多巴胺的剂量从0.26×10~(-6)mol/kg-1.58×10~(-6)mol/kg逐步增加,其对伤害性经皮电刺激诱发的背角神经元后串放电的抑制作用也随之加强;0.52×10~(-6)mol/kg多巴胺的作用在给药后5min即出现,15min达高峰并在此后的25min基本维持在同一水平,这个作用可被静注多巴胺能受体拮抗剂氟哌啶(0.66×10~(-6)mol/kg)完全翻转,而不受静注酚妥拉明(2.65×10~(-6)mol/kg)和纳洛酮(1.37×10~(-6)mol/kg)影响。上述结果表明,多巴胺可能是参与脊髓水平伤害性信息传递调控的另一单胺类神经递质。     

FORMATION OF SEROTONIN BY ISOLATED SEROTONIN-CONTAINING NEURONS AND BY ISOLATED NON-AMINE-CONTAINING NEURONS

Isolated giant serotonin-containing neurons of the cerebral ganglia of Helix pomatia were shown to produce serotonin when incubated with 5-hydroxytryptophan (5-HTP) whereas cells of the buccal ganglia, which are non-amine-containing cells did not. The rate of production was comparable to that for Ach in the isolated neurons of Aplysia. The significance of these results is discussed.     

ERYTHROID CELL DIFFERENTIATION AND THE INHIBITION OF CYTOKINESIS BY CYTOCHALASIN

Cytochalasin B produces multinucleated erythroid cells in tissue cultures of very young chick blastoderms. There is no apparent qualitative interference with differentiation and maturation of erythroid cells, but the amounts produced are reduced 4- and 10-fold. These effects of cytochalasin are readily reversible.