Intranasal administration delivers peptoids to the rat central nervous system

Intranasal administration of therapeutic agents offers a noninvasive method of drug delivery that bypasses the blood–brain barrier and directly targets the central nervous system (CNS) and lymph nodes. We examined whether intranasal peptoid CHIR5585, an antagonist of the urokinase plasminogen activator receptor (uPAR), is delivered to the CNS. Peptoids are a novel class of peptide isomers that are oligomeric N-substituted glycine peptides. Anesthetized male rats were administered peptoid CHIR5585 intranasally, and tissue distribution was evaluated quantitatively by gamma counting and qualitatively by autoradiography. Intranasal administration resulted in significant delivery throughout the CNS (olfactory bulbs, 3.9 μM; cortex, 0.3 μM; trigeminal nerve, 1.7 μM) and deep cervical lymph nodes (4.5 μM). Autoradiography demonstrated a similar delivery pattern to the CNS.     

Caspase-3在大鼠中枢神经系统的表达研究

目的研究caspase-3在大鼠中枢神经系统的表达及其意义。方法用western-blot方法对出生1天和3个月SD大鼠的大脑皮质、中脑和小脑组织的caspase-3进行半定量测定。结果出生1天大鼠脑的caspase-3表达较高,出生3个月大鼠脑的caspase-3表达较低。结论caspase-3在中枢神经系统的发育成熟过程中对神经元的凋亡起着关键性作用。     

Colchicine induces enhanced intestinal permeability in the rat

Intestinal permeability was determined in rats receiving colchicine 0.5 ± 0.15 mg day^-1 in drinking water (30 mg L^-1) for periods up to 23 days. The lactulose/mannitol method was used to determine whole gut permeability before and on days 2, 4, 8, 18 and 23 of colchicine administration. The 8-h urinary lactulose excretion following the test meal increased significantly in rats receiving colchicine, compared with the pretreatment value. Increased lactulose permeability was present after 2 days and remained stable throughout the experimental period. Mannitol urinary excretion was not changed. Colchicine increases intestinal tight junction permeability by an as yet undetermined mechanism.     

Macrophages in the central nervous system of the rat

In an immunohistochemical study using monoclonal antibodies, which exclusively recognize cells of the monocyte-macrophage lineage, and monoclonal antibodies against the Ia-antigen, we describe the occurrence of macrophages in the developing and adult central nervous system (CNS). In normal adult brain, no macrophages could be detected in the CNS parenchyma; only in the meninges and the choroid plexes were a few macrophages found. During ontogeny, numerous phagocytic cells infiltrated the CNS parenchyma; these cells which did not express Ia are blood-borne. About three weeks after birth, all macrophages had disappeared from the CNS. As microglia in adult and developing brain do not stain with the anti-macrophage antibodies, we suggest that microglial cells are not related to the mononuclear phagocyte system and do not have a hematogenous origin.     

IgGimmunoreactivities(IgGIR) in the rat central nervous system following administration of the antineurons antibody

以猪脊髓运动神经元（Ｍｎｓ）为抗原免疫Ｂａｌｂ／ｃ小鼠制备抗Ｍｎｓ抗体（ＭｃＡｂ,３６Ｆ６）,该抗体与人和大鼠脊髓Ｍｎｓ有交叉反应。把这些ＩｇＧ抗体注射到肌肉中,ＩｇＧ便经逆行轴浆运输到Ｍｎｓ胞体,而不进入到感觉神经元。用改变的ＡＢＣ方法定位大鼠中枢神经系统的小鼠的ＩｇＧ免疫反应（ＩｇＧ－ＩＲ）。肌肉注射３６Ｆ６后,动物存活４８－７２ｈ,ＭｃＡｂ跨细胞作用可能发生从逆行标记的Ｍｎｓ到Ⅷ、Ⅹ板层（在脊髓水平）,甚至到脑干网状结构的神经元。在同一切片上,网状结构内出现了神经元的跨细胞作用。ＩｇＧ－ＩＲ细胞还可分布在下丘脑室旁核、视上核、新皮质和室管膜细胞以及不规则出现的血管周的胶质细胞和／或神经元。     

Presence of SNAP-25 in rat mast cells

Mast cells participate in inflammation and allergies by releasing active mediators stored in numerous cytoplasmic granules. Degranulation implies compound exocytosis which involves a combination of granule-granule and granule-plasma membrane fusions. One of the most important proteins in the exocytotic process in neural and endocrine cells is the synaptosomal associated protein of 25 kDa (SNAP-25). In the present study, using a highly specific monoclonal antibody against SNAP-25, we have demonstrated by immunocytochemistry, western blot and immunoelectron microscopy the presence of SNAP-25 in rat peritoneal mast cells. Likewise we localized the protein mainly on the membrane of the secretory granules. Thus while the precise function of SNAP-25 in mast cells remains to be elucidated, it may be envolved in granule-granule fusion needed in degranulation.     

p53 protein expression in central nervous system neoplasms.

AIMS: To demonstrate, immunohistochemically, p53 protein expression in a selection of central nervous system tumours; to investigate the relation between p53 expression and that of the proliferation related antigen, PCNA. METHODS: Surgical specimens from 86 central nervous system tumours were routinely fixed, paraffin wax embedded, and immunostained with a monoclonal (PAb 1801) and a policlonal antibody (CM1) p53 protein and a monoclonal antibody against PCNA (PC10). Normal brain samples obtained at necropsy and 10 surgically obtained samples of gliotic brain parenchyma were also immunostained. RESULTS: p53 protein expression was observed in 35 of 86 brain tumours, suggesting frequent p53 gene mutation. p53 protein alterations were associated with all grades of malignancy in tumours displaying solely astrocytic differentiation, with the exception of pilocytic astrocytomas. In those showing oligodendroglial or ependymal differentiation they appeared to be restricted almost to only high grade lesions. No p53 immunoreactivity was observed in normal or gliotic brain tissue; p53 altered expression was not related to the percentage of PCNA labelled cells. CONCLUSIONS: The use of sophisticated gene amplification techniques or highly sensitive immunohistochemical methods might be useful in distinguishing between reactive and neoplastic astrocytic lesions, and in the identification of malignant progression in other non-astrocytic glial tumours. Tumours with very similar histogenetic differentiation features might actually be a genetically heterogeneous group with possible different clinical courses.     

CuZn-SOD promoter-driven expression in the Drosophila central nervous system

The aim of this study was to ascertain the status of CuZn superoxide dismutase (CuZn-SOD) expression in the central nervous system of Drosophila melanogaster. Immunoblot analysis of dissected tissue extracts revealed low levels of the CuZn-SOD protein in adult brains relative to other adult and larval tissues. To explore further this observation, three different reporter constructs containing different elements of the CuZn-SOD promoter domain were used for the generation of transgenic flies. A high level of reporter gene expression occurred during the second wave of neurogenesis (third instar and early pupal stages) in scattered, proliferating neuroblasts (NBs) and in proliferation centers of the optic lobe. In mature, postmitotic neurons, this expression was lower relative to other tissues. In adult flies, at all ages examined, there was little if any detectable reporter gene expression in cells of the central nervous system. These results suggest that one of the key components of the antioxidant defenses, CuZn-SOD, is quite low in postmitotic neural tissue, rendering it particularly susceptible to oxidative damage during aging.     

Cation-dependent structures associated with membranes in the rat central nervous system.

As observed by high magnification electron microscopy, potassium ions induce osmiophilia at the extracellular side of triple layered plasma membranes in the central nervous system of the rat. In contrast, sodium ions induce a widening of the intracellular lamina of these membranes, and do not result in observable extracellular deposits. The observations suggest the existence of potassium and sodium ion-selective structures associated with opposite surfaces of the neuron membrane. Use of the fixative vehicle as a cytochemical reagent is proposed.     

Dynorphin-immunoreactive neurons in the central nervous system of the rat

An antiserum specific for the C-terminal region of dynorphin_1–17 (DYN) was used to examine the distribution of this endogenous opioid peptide in the rat brain with the indirect immunofluorescence technique. DYN-positive nerve cell bodies and fibers were found in many nuclei in the spinal cord, medulla, mesencephalon, hypothalamus and forebrain. These findings indicate that a widespread system of DYN neurons is present in the brain distinct from the previously described enkephalin and endorphin systems.     

Localization of aggrecan and versican in the developing rat central nervous system.

The localization of aggrecan and mRNA splice variants of versican in the developing rat central nervous system has been examined by using specific polyclonal antibodies to the nonhomologous glycosaminoglycan attachment regions of these hyaluronan-binding chondroitin sulfate proteoglycans. At embryonic day 16 (E16), aggrecan and versican splice variants containing either or both the alpha-and beta-domains are present in the marginal zone and subplate of the cerebral cortex and in the amygdala, internal capsule, and the optic and lateral olfactory tracts. There is strong staining of versican but not of aggrecan in the hippocampus and dentate gyrus by E19, whereas both aggrecan and alpha-versican are present in the fimbria. At E19, aggrecan is seen throughout the cerebral cortex, whereas the distribution of versican is considerably more limited, being confined essentially to the marginal zone and subplate. At 1 week postnatal, both aggrecan and versican are present in the prospective white matter and in the molecular and granule cell layers of the cerebellum, but neither proteoglycan is seen in the external granule cell layer. alpha- but not beta-versican staining is seen in Purkinje cells, and aggrecan staining of Purkinje cells is also rather minimal. In the spinal cord at E13, aggrecan is present in the dorsal root entry zone, ventral funiculus, mantle layer, and floor plate, as well as in the dorsal root ganglia and ventral roots. However, alpha-versican is confined to the dorsal root entry zone and the ependyma surrounding the spinal canal, and beta-versican is not present in spinal cord parenchyma at this developmental stage, being limited to the surrounding connective tissue. By E19, there are significant amounts of all three proteoglycans in the spinal cord. Aggrecan staining is most intense in the lateral funiculus and the fasciculi gracilis and cuneatus, where alpha-versican staining is also strong. In contrast, beta-versican is seen predominantly in the motor columns. Differences in the localization and temporal expression patterns of these chondroitin sulfate proteoglycans suggest that, like neurocan and phosphacan, they have partially complementary roles during central nervous system development.     

Oral motor deficits following lesions of the central nervous system in the rat.

The effects of lesions of the zona incerta (ZI), globus pallidus (GP), midlateral and far lateral hypothalamus (MLH and FLH), and the central amygdaloid complex (CAC) on oral motor deficits were investigated. Lesions of the ZI, GP, and CAC resulted in a significant reduction in tongue extension and lap volume. MLH lesions significantly reduced tongue extension whereas FLH lesions significantly reduced both tongue extension and lap volume. Injections of 6-hydroxydopamine into the GP, MLH, and CAC also significantly reduced tongue extension and lap volume. Water and/or food intakes were reduced in some of the lesioned groups but the oral motor deficits were observed both in the presence and in the absence of reduced water and food intakes. The possibility that oral motor deficits are associated with damage to striatal and non-striatal dopamine neurons needs further investigation.     

Thiamine transport in the central nervous system.

Total thiamine (free thiamine and thiamine phosphates) transport into the cerebrospinal fluid (CSF), brain, and choroid plexus and out of the CSF was measured in rabbits. In vivo, total thiamine transport into CSF, choroid plexus, and brain was saturable. At the normal plasma total thiamine concentration, less than 5% of total thiamine entry into CSF, choroid plexus, and brain was by simple diffusion. The relative turnovers of total thiamine in choroid plexus, whole brain, and CSF were 5, 2, and 14% per h, respectively, when measured by the penetration of 35S-labeled thiamine injected into blood. From the CSF, clearance of [35S]thiamine relative to mannitol was not saturable after the intraventricular injection of various concentrations of thiamine. However, a portion of the [35S]thiamine cleared from the CSF entered brain by a saturable mechanism. In vitro, choroid plexuses, isolated from rabbits and incubated in artificial CSF, accumulated [35S]thiamine against a concentration gradient by an active saturable process that did not depend on pyrophosphorylation of the [35S]thiamine. The [35S]thiamine accumulated within the choroid plexus in vitro was readily released. These results were interpreted as showing that the entry of total thiamine into the brain and CSF from blood is regulated by a saturable transport system, and that the locus of this system may be, in part, in the choroid plexus.     

Folate transport in the central nervous system.

Methyltetrahydrofolic acid or folic acid was infused intravenously at a constant rate into conscious untreated or methotrexate-pretreated rabbits. After 150 min, at equivalent plasma concentrations, folic acid or methyltetrahydrofolic acid readily entered the cerebrospinal fluid and probably brain by a saturable transport system. In contrast, after intraventricular injections, folic acid but not methyltetrahydrofolic acid was cleared from cerebrospinal fluid to blood by a saturable system. Intraventribular injection of folic acid at concentrations that saturated folic acid clearance from cerebrospinal fluid did not affect the transport of methyltetrahydrofolic acid from blood into cerebrospinal fluid. These results suggest that the transport system for mehtyltetrahydrofolic acid, which is about half-saturated at normal plasma concentrations, helps maintain the cerebrospinal fluid and probably brain methyltetrahydrofolic acid concentrations within relatively narrow limits. Moreover, folic acid, which the brain cannot utilize, is transported from cerebrospinal fluid. A possible locus for the systems that transport folic acid from and methyltetrahydrofolic acid into the cerebrospinal fluid is the choroid plexus.