Radiation chemistry of a multicomponent aqueous system relevant to chemistry of cometary nuclei

Summary We have examined a water-dominated multicomponent system after irradiation in the multimegarad dose range with gamma rays from a⁶⁰Co source at both 77 and 310 K. The constituents were simple organic compounds in the proportions in which they appear in a dense interstellar cloud: HCN/CH₃OH/CH₃CN/C₂H₅CN/HCOOH=10.60.20.10.05. The total amounts were adjusted to correspond to a carbon to nitrogen ratio of 1.8 and a water content of about 50% in a cometary nucleus where the dust to volatiles ratio is 1; the total amount of CN-bearing compounds was taken to correspond to 0.4% of the cometary mass. In experiments at 310 K about 40 radiolytic products are identified, among them aldehydes and amino and carboxylic acids. Abundant polymeric material (M_w up to 80,000 daltons) is formed. The basic aspects of radiolysis of the liquid system are present also at 77 K, although at radiation-chemical yields that are lower by one to two orders of magnitude. We have considered the relevance of the present findings to the chemistry of a liquid-water core and the icy layers of a cometary nucleus.     

Effect of Unilateral Decortication on Choline Acetyltransferase Activity in the Nucleus Basalis and Other Areas of the Rat Brain

Acetyl-coenzyme A: choline O-acetyltransferase (EC 2.3.1.6) (ChAT) enzyme activity was measured in the nucleus basalis and other microscopically identified brain areas at various times after unilateral cortical lesions were made in the rat. Initially, a significant decrease in ChAT activity was detected in the nucleus basalis ipsilateral to the lesion. However, after 120 days ChAT activity had apparently recovered, as levels of the enzyme at that time were not significantly different from control values. No changes in ChAT activity could be detected in any of the other brain areas similarly studied. The significance of these findings and their relationship to the morphological changes seen in neurones of the nucleus basalis after cortical lesions are discussed.     

Cholinesterases in Single Nerve Cells Isolated from the Locus Ceruleus and from Nucleus of the Facial Nerve of the Rat: A Microgasometric Study

Cholinesterase activity in single nerve cell bodies isolated from the locus ceruleus and nucleus of the facial nerve of the rat was analyzed by the microgasometric method. Acetylcholinesterase activity is about the same in both types of cells. Nonspecific cholinesterase is present in noradrenergic cells of the locus ceruleus but not in the cholinergic cells of the nucleus of the facial nerve. The total activity of cholinesterases and the activity of acetylcholinesterase in nerve cell bodies isolated from the locus ceruleus remains practically unchanged from the tenth postnatal day until the age of 24 months. Depletion of noradrenaline by a high dose of reserpine does not influence the total activity of cholinesterases in nerve cell bodies of locus ceruleus.     

Relationship of ACTH1-39-immunostained fibers and magnocellular neurons in the paraventricular nucleus of rat hypothalamus

Dual antigen immunocytochemical staining procedures were used in the same tissue section to determine the distribution of ACTH immunostained fibers and varicosities within the magnocellular and parvocellular divisions in the paraventricular nucleus (PVN) of rat hypothalamus and elucidate its anatomical relationship to vasopressin (VP) and oxytocin (OXY)-containing neurons. Double immunostained preparations using glucose oxidase-antiglucose oxidase complex combined with PAP complex to visualize two antigens with contrasting colors in the same tissue section were employed. ACTH-immunoreactive (ir) fibers were distributed throughout the periventricular stratum and the parvocellular component of the PVN; in the latter area fibers were particularly dense in the ventral medial portion of the medial parvocellular division. Dual immunostained sections revealed a close anatomical association between opiocortin fibers and oxytocin and vasopressin parvocellular neurons. ACTH immunostained fibers were present in the anterior and medial magnocellular component of PVN and in the ventral medial portion of the posterior magnocellular division; these immunoreactive fibers were in intimate proximity to oxytocin-ir perikarya. The very close approximation between the ACTH-ir fibers and oxytocin-containing cell bodies suggests potential cell to cell communication between the two peptidergic systems in PVN. Few ACTH immunostained fibers were seen in the dorsal lateral portion of the posterior magnocellular division in which vasopressinergic neurons predominate. The present anatomical study supports pharmacological and physiological studies which indicate that opioids can influence the activity of magnocellular PV neurons. This study also elucidates an anatomical relationship between opiocortins (ACTH1-39) and parvocellular PV neurons which suggests that the opiocortin system may play a role in the regulation of both the neuroendocrine and autonomic activities of specific PV neurons.     

关于猫颌下腺神经支及其节前神经元的观察

用逆行溃变（Kohnstamm,1902;Yagita,et al.,1909;Torvik,1957）局部电刺激中枢（Chatfield,1942;Magoun et al.,1942;Wang,1943）等方法进行唾液中枢的定位,所得到结果很不一致。近年Satomi（1979）等用辣根过氧化酶（HRP）浸泡猫中间一面神经或鼓索神经,观察了脑干中逆行标记细胞的分布。但用HRP直接浸泡支配猫颌下腺的神经分支尚未见报道。此外,只见到关于鼓索神经纤维类别和数量的分析的光学显微镜研究（Foley,1945）,用光镜和电镜相结合分析颌下腺神经支中的纤     

Blood supply of the bed nucleus of the stria terminalis in rat

Summary The topographical distribution of the blood vessels in the bed nucleus of the stria terminalis (NIST) has been mapped in rats. Arteries and veins were visualized in red and blue by using a double-ink perfusion technique. Arteries supplying the NIST arise from the anterior cerebral artery directly or through the anterior communicating and interhemispheric arteries. Only a few, dorsal branches derive from the medial cerebral artery through thalamostriatal arteries. According to their terminal branches, NIST arteries can be divided into five groups: medial, ventral, lateral, septal and dorsal, which have only a relatively small overlap in their territories. About 90% of veins from the NIST drain into the major basal veins. Medial branches run into the perioptic and interhemispheric veins, while the ventral branches and the large lateral vein drain directly into the anterior cerebral vein. A small proportion of NIST veins run dorsalward into the vena cerebri magna via thalamostriatal veins.     

Effects of steroid hormones on the neuropil of the hypothalamic paraventricular nucleus of male chickens

Summary Testosterone and corticosterone, administered in doses of 0.5 mg/day for two weeks to three-day-old male chickens, induced alterations in the distributional pattern and in the number of synapses in the rostral neuropil of the hypothalamic paraventricular nucleus. This avian nucleus is a target area for both above-mentioned hormones and also one of the most important centers involved in the regulation of behavioral patterns related to reproduction. Testosterone increased the number of synapses in the rostral paraventricular nucleus, while corticosterone altered their distributional pattern causing an increase in type-B terminals; according to morphological criteria the latter are regarded to represent aminergic endings. Similar results were induced by simultaneous administration of both testosterone and corticosterone. Precocious sexual behavior was also provoked by double treatment.Preliminary results have been presented on the occasion of the 5th ENA meeting (Liège, Belgique, Sept. 1981) and the 1st Italian Meeting of Cell Biology (Rimini, Italy, April 1982)This study was supported by CNR bilateral grants (82.00215.04 & 83.00492.04), MPI 40% and European Training Program in Brain and Behaviour Researchs (twinning grant)     

Lactation-associated redistribution of the glial fibrillary acidic protein within the supraoptic nucleus

Summary Three clones of myeloproliferative virus (MPV)-transformed rat fibroblasts (NRK) with different growth properties and morphology were transplanted to athymic nude mice. Presence of carbohydrate-binding proteins was inferred by fluorescence microscopy using fluorescent, glycosylated markers. Salt and detergent extracts of tumors from this model system were fractionated under identical conditions on different sets of Sepharose columns, to which lactose, asialofetuin, melibiose, mannan and fucose had been covalently linked. Successive elution by chelating reagent and specific sugar resulted in isolation of the different Ca²⁺-dependent and Ca²⁺-independent endogenous carbohydrate-binding proteins that were assayable as agglutinins. In comparison, the different tumors displayed a pattern with qualitative and quantitative alterations. Since protein-carbohydrate interaction mediated by carbohydrate-binding proteins (lectins) is of importance for cognitive processes, it is remarkable that the pattern of membrane glycoproteins, isolated by affinity chromatography on resins with immobilized plant lectins, had also been found to reveal certain individual properties for receptors specific for peanut agglutinin (PNA) and Ulex europaeus agglutinin (UEA). These demonstrated differences within the system of protein-carbohydrate interaction suggest that endogenous lectins and their ligands have potential significance as markers defining a certain phenotype within this tumor model system.Dedicated to Prof. Dr. W. Lamprecht on the occasion of his 60th birthday     

蓝斑复合核区内微量注射去甲肾上腺素对刺激兔下丘脑诱发室性期前收缩的影响

在72只乌拉坦、氯醛糖麻醉兔,静脉注射三碘季铵酚后,在人工呼吸下进行实验。结果观察到,在家兔蓝斑复合核(Lo-So)区微量注射去甲肾上腺素(NE)或可乐宁(Clonidine)能减少刺激下丘脑诱发的室性期前收缩(HVE)数。而微量注射β-肾上腺素能受体阻断剂心得安、α_1肾上腺素激动剂甲氧胺(Methoxamine)或苯肾上腺素(Phenylephrine)、α肾上腺素能阻断剂育亨宾(Yohimbine)或阿片受体阻断剂纳洛酮则对 HVE 无明显影响。在 Lo-So 区微量注射 NE 对 HVE 的抑制效应不能被事先在该区注射心得安所阻断但能被事先静脉或 Lo-So 区注射育亨宾所阻断。NE 或可乐宁的抑制效应也均可被育亨宾所翻转。可乐宁的抑制效应还可被纳洛酮所翻转。电解损毁延髓中缝大核区可消除在 Lo-So 区微量注射 NE 或可乐宁对HVE 的抑制效应。上述结果提示,Lo-So 区α_2受体的兴奋可减少 HVE 数,这些作用可能依赖于延髓中缝大核区的完整。可乐宁对 HVE 的抑制作用可能有阿片受体的参与。     

中缝大核在臂旁内侧核区注射吗啡所致呼吸抑制效应中的作用

实验在33只浅麻醉、肌肉麻痹、人工呼吸及切断双侧颈迷走神经的家兔上进行。观察中缝大核区电解损毁或微量注射利多卡因对呼吸活动及臂旁内侧核区微量注射吗啡所致呼吸抑制效应的影响。结果是:电解损毀中缝大核区,使呼吸频率增加,膈神经放电的幅度和频率均无明显变化,而臂旁内侧核区微量注射吗啡抑制呼吸的程度减轻;中缝大核区微量注射利多卡因,则部分消除臂旁内侧核区微量注射吗啡的呼吸抑制效应。中缝大核旁网状结构电解损毁或微量注射利多卡因,不影响吗啡的呼吸抑制效应。上述结果提示,中缝大核区可能在脑桥臂旁内侧核区微量注射吗啡抑制呼吸的机制中起一定作用。