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At least 91 records · Page 5Linked to original sources

PubMed1998

Murine leukemia virus recombinants that use phosphate transporters for cell entry induce similar spongiform encephalomyelopathies in newborn mice.

Amphotropic Moloney-murine leukemia virus recombinants (Mo-AmphoV) induce a severe spongiform encephalomyelopathy in newborn mice. We show here that a coisogenic recombinant with a 10A1-MuLV host range (Mo-10A1V) also induces a neurodegenerative disease, clinically characterized by mild tremor and ataxia. Spongiform lesions are most severe in the metencephalon and mesencephalon but extend into the prosencephalon and spinal cord. Significantly, the quality of histopathology was indistinguishable between Mo-AmphoV and Mo-10A1V, probably reflecting a final common pathogenic pathway. Common receptor use thus may be an important determinant in the pathogenicity of these viruses. These results have implications for the clinical use of retroviral pseudotypes that use phosphate transporters for cell entry.

3T3 Cells↗

PubMed1990

Association of cephalic neural crest cells with cardiovascular development, particularly that of the semilunar valves.

The quail-chick chimera method was used to examine whether neural crest cells were associated with the formation of semilunar valves. From the metencephalon to somite 5, or from the otocyst to somite 3, left, right, or bilateral neural folds, including the neural crest, were transplanted. Among embryos used for the experiment, three into which left neural crest cells were transplanted, two into which right neural crest cells were transplanted, and two into which bilateral neural crest cells were transplanted had a morphologically normal heart. In these embryos, neural crest cells were found in all cusps of the aortic and pulmonary semilunar valves. Although neural crest cells have been thought to have no association with the formation of the semilunar valves, our experiment indicates that such association indeed occurs.

Animals↗

PubMed1991

The efferent connections of the lateral septal nucleus in the guinea pig: projections to the diencephalon and brainstem.

The anterograde Phaseolus vulgaris-leucoagglutinin (PHA-L) tracing technique was used to determine the distribution of efferent fibers originating in the lateral septal nucleus of the guinea pig. For complementary detection of the chemical identity of the target neurons, double-labeling immunocytochemistry was performed with antibodies to PHA-L and to vasopressin, oxytocin, vasoactive intestinal polypeptide, serotonin or dopamine beta-hydroxylase, respectively. The hypothalamus received the majority of the PHA-L-stained septofugal fibers. Here, a specific topography was observed. (1) The medial and lateral preoptic area, (2) the anterior, lateral, dorsal, posterior hypothalamic and retrochiasmatic area, (3) the supraoptic, paraventricular, suprachiasmatic, dorsomedial, caudal ventromedial and arcuate nuclei, and (4) the tuberomammillary, medial and lateral supramammillary, dorsal and ventral premammillary nuclei always contained PHA-L-labeled fibers. The rostral portion of the ventromedial nucleus and the medial and lateral mammillary nucleus only occasionally showed weak terminal labeling. In other diencephalic areas, termination of PHA-L-labeled fibers was observed in the epithalamus and the nuclei of the midline region of the thalamus. In the mesencephalon, terminal varicosities occurred in the ventral tegmental area, interfascicular and interpeduncular nucleus, and periaqueductal gray. In addition, the dorsal and medial raphe nuclei of the metencephalon, together with the locus coeruleus and the dorsal tegmental nucleus, received lateral septal efferents.

Animals↗

PubMed1990

The Purkinje cell class may extend beyond the cerebellum.

The cerebellum develops from a germinal zone at the rhombic lip of the metencephalon. This region, like the telencephalic vesicle which gives rise to the cerebral cortex, presumably consists of germinative units showing a rather repetitive neurogenetic pattern. In all cerebellar folia, cortical neurons, and especially the Purkinje cells, express highly stereotyped phenotypes, although some variations in their chemical make-up have been uncovered with monoclonal antibodies. Here, we demonstrate for the first time that three independent murine mutations, Lurcher, Purkinje cell degeneration and staggerer, which result in the postnatal degeneration of Purkinje cells, also cause the elimination of cartwheel cells of the dorsal cochlear nucleus. The cerebellar granule cell mutation, weaver, which spares most Purkinje cells in the lateral cerebellum, also spares cartwheel cells. These data support the notion that the cerebellar germinative zone extends to the caudal portion of the rhombic lip, which gives rise to the dorsal cochlear nucleus.

Animals↗

PubMed1978

Persistent embryonic veins in arteriovenous malformations of the brain.

The course and direction of persistent foetal venous channels are easily defined in the relatively simple segmental portions of the nervous system, such as the spinal cord, the myelencephalon, the metencephalon, and the mesencephalon. In sites were embryonic development is more complicated, like the diencephalon and the telencephalon, rapid growth and folding of the cortex complicate the patterns of the foetal blood vessels. Arteriovenous malformations in such sites are correspondingly more complex.

Cerebral Angiography↗

PubMed2000

Reconstructing the pathway of the tensor veli palatini motor nerve during early mouse development.

The motor axons innervating the tensor veli palatini (TVP) navigate a long distance from the trigeminal motor nucleus to their target. The pathway and time course of the TVP motor nerve during this navigation process remain poorly understood. The aim of this study was to elucidate the peripheral development of the TVP motor nerve, and to confirm when the morphological relationship is established between the nerve and target muscle progenitors. Using immunohistochemistry, carbocyanine fluorescent labeling, and computerized three-dimensional image-reconstruction methods, we demonstrated the development of the TVP motor nerve in mouse embryos. Further, the morphological relationship between the extending mandibular nerve and myogenic cells stained for MyoD1 was examined. The peripheral pathfinding of the TVP motor nerve was divided into three continuous stages: (1) the earliest trigeminal motor axons leave the metencephalon and enter the primordium of the trigeminal ganglion at E9.5, when MyoD1-positive cells can already be detected in the mesenchymal core of the mandibular arch; (2) converging with the sensory root, the trigeminal motor root excites the trigeminal ganglion and begins to approach the mandibular muscle precursors at E10.5; (3) collateral branching occurs at E12.5. By E13.5, a nerve branch splits from the mandibular nerve to innervate the TVP, which appears as an individual muscle mass. These results suggest that the early process of mandibular motor nerve extension is correlated with the trigeminal ganglion cells, whereas when growing out of the ganglion, the mandibular nerve has a close relationship with target myogenic cells throughout the later process of pathway finding.

Acetylcholinesterase↗

PubMed2006

Localisation and distribution of O-acetylated N-acetylneuraminic acids, the endogenous substrates of the hemagglutinin-esterases of murine coronaviruses, in mouse tissue.

Infections by mouse hepatitis viruses result in disease of the liver, the gastrointestinal tract, respiratory tract, and the central nervous system. Coronaviruses related to mouse hepatitis virus express a hemagglutinin-esterase surface glycoprotein, which specifically hydrolyses either 5-N-acetyl-4-O-acetyl neuraminic acid (Neu4,5Ac(2)) or 5-N-acetyl-9-O-acetyl neuraminic acid (Neu5,9Ac(2)). Moreover, these sialic acids represent potential cellular receptor determinants for murine coronaviruses. Until now, the distribution of these sialic acids in mouse brain was not thoroughly investigated. Particularly Neu4,5Ac(2) was not yet found in mouse brain. Using a sensitive method of gas chromatography coupled to mass spectrometry in the electron impact mode of ionization this manuscript demonstrates the occurrence of 13 different sialic acids varying in their alkyl and acyl substituents in mouse tissues including 5-N-acetyl-4-O-acetyl-9-O-lactyl-neuraminic acid (Neu4,5Ac(2)9Lt), 5-N-acetyl-9-O-lactyl-neuraminic acid (Neu5Ac9Lt), 5-N-acetyl-8-O-methyl-neuraminic acid (Neu5Ac8Me) and the 1,7-lactone (Neu5Ac1,7L) of neuraminic acid. Neu4,5Ac(2), relatively abundant in the gut, was present as a minor compound in all tissues, including liver, olfactory lobe, telencephalon, metencephalon and hippocampus. Neu5,9Ac(2) was also found in these tissues, except in the liver. It is suggested that these sialic acids represent the endogenous substrate and receptor determinants for murine coronaviruses.

Acetylation↗

PubMed1985

Pontine and mesencephalic substrates of self-stimulation.

Single or twin, moveable monopolar stimulating electrodes were implanted in male adult rats in order to map the medial pons and mesencephalon for self-stimulation behaviour. The electrodes were implanted 6 mm below the surface of the skull and subsequently moved down by steps of 0.13 or 0.16 mm. Each bar press in a Skinner box delivered a train (0.4 s in duration) of cathodal rectangular pulses of fixed intensity (200 microA) and width (0.1 ms). Self-stimulation was recorded from zero to the maximum performance by varying the number of pulses per stimulating train. The rewarding efficacy of the stimulation at each electrode location was inferred from determination of the pulse period corresponding to the threshold and half-maximal performance. Out of 361 mesencephalic and pontine sites sampled, 289 supported self-stimulation. Within the metencephalon, the study revealed a continuous band of positive sites, extending over a dorso-ventral distance of 4 mm, between the floor of the aqueduct and the pontine nuclei. Hence, all electrode locations in the central grey, dorsal raphe and median raphe supported self-stimulation. Within the mesencephalon, the positive band was restricted between the floor of the central grey and the middle part of the interpeduncular nucleus. At the rostral mesencephalon, it shifted laterally towards the substantia nigra. The overlap between the self-stimulation sites and some of the best known ascending and descending pathways is discussed.

Animals↗

PubMed1988

Autoradiography of [3H]U-69593 binding sites in rat brain: evidence for kappa opioid receptor subtypes.

In vitro quantitative autoradiography was used to determine the distribution of [3H]U-69593 binding sites in rat brain. The highest density of binding was found in areas of the tel- and diencephalon while certain areas of the mes- and metencephalon were moderately labeled. The distribution of [3H]U-69593 binding sites corresponds closely (but not precisely) to the distribution of sites labeled by [3H]EKC and [3H]bremazocine at room temperature but differs substantially from the distribution of sites labeled by [3H]EKC at 4 degrees C (as described by others). These anatomical findings support previous biochemical evidence indicating that [3H]U-69593 selectively labels a kappa opioid receptor subtype with characteristics that differ from the kappa receptors labeled by [3H]EKC at 4 degrees C.

Analgesics↗

PubMed1991

Temporal distribution of retinoic acid and cellular retinoic acid-binding protein (CRABP) in the fetal hamster.

The temporal relationship between the distribution of retinoic acid, a known human and rodent teratogen, and that of cellular retinoic acid-binding protein (CRABP) was investigated from Day 11 to Day 14 of hamster prenatal development. The 11,12-(3)H2 and 15(-14C) forms of all-trans-retinoic acid were used for quantitative distribution studies and autoradiography, respectively, and were evaluated 15 min after a single intravenous injection. Radioactivity was detected in all fetal tissues examined (brain, liver, heart, spinal cord, limb, and skin), and at Day 14, approximately 66% of the total radioactivity was present as parent all-trans-retinoic acid. High concentrations of total radioactivity were observed by autoradiography in the midbrain and hindbrain (mesencephalon, metencephalon, and myelencephalon) and spinal cord, but not in the forebrain. At the earliest time studied, limb buds showed relatively high concentrations of radioactivity. Levels of radioactivity were also high in portions of the developing face, nose, and tongue. Immunohistochemical analyses indicated that the amount of CRABP in Day 14 tissues was the highest in spinal cord followed by limb and skin; heart and liver contained only relatively small amounts of this protein. From Day 11 to Day 14, the amount of CRABP, as measured by high-performance size-exclusion liquid chromatography, in the whole body decreased as gestation progressed. Microscopic immunohistochemical localization of CRABP found the highest concentration in the ventral midbrain and in the ventral and lateral sides of the hindbrain and spinal cord; CRABP was also abundant in tongue, limb, and skin. The distribution of CRABP-positive cells in the central nervous system was similar to the distribution of retinoic acid. The data presented here indicate that fetal CRABP appears to play a role in differential accumulation of retinoic acid in certain structures of the developing hamster. The patterns of tissue retinoid and CRABP distribution observed here are consistent with the patterns of congenital malformations induced by prenatal retinoid exposure.

Animals↗

PubMed1993

Effect of maternal adrenal deprivation on the content of catecholamines in fetal brain.

Previous studies performed in our laboratory showed the importance of the effects that the absence of maternal adrenal hormones have on fetal brain. In the present study we investigated the effect of adrenal deprivation during gestation on the fetal catecholamines development in several cerebral areas. Fetuses from both control and adrenalectomized mothers from the first day of gestation were removed on the 20th embryonary day. Plasma corticosterone levels were significantly lower in the maternal serum of adrenalectomized rats, while the contents were non significantly higher in the adrenalectomized-mothers group of fetuses. Catecholamine contents in diencephalon, metencephalon, mesencephalon and telencephalon were measured by HPLC-ED. The results obtained showed that when the development of the catecholaminergic systems was previous enough to the fetal adrenal function, and under maternal adrenal deprivation conditions, the lack of corticosterone promotes an increase in the level of the catecholamines, as observed in the diencephalic NA, the earlier in maturational process. In those areas where the maturation starts at the same time than the fetal adrenal hypersecretion, no changes were observed. In the cortex, where both DA and NA develop later, the corticosterone produces an inhibition in the proliferation of the catecholaminergic neurons, showing decreased telencephalic levels of both catecholamines.

Adrenal Glands↗

PubMed1990

The Wnt-1 (int-1) proto-oncogene is required for development of a large region of the mouse brain.

The Wnt-1 (int-1) proto-oncogene, which encodes a putative signaling molecule, is expressed exclusively in the developing central nervous system and adult testes. To examine the role of Wnt-1, we generated six independent embryonic stem cell lines in which insertion of a neoR gene by homologous recombination inactivated a Wnt-1 allele. Germline chimeras were generated from two lines, and progeny from matings between heterozygous parents were examined. In all day 9.5 fetuses homozygous for mutated Wnt-1 alleles, most of the midbrain and some rostral metencephalon were absent. The remainder of the neural tube and all other tissues were normal. In late-gestation homozygotes, there was virtually no midbrain and no cerebellum, while the rest of the fetus was normal. Homozygotes are born, but die within 24 hr. Thus the normal role of Wnt-1 is in determination or subsequent development of a specific region of the central nervous system.

Alleles↗

PubMed1989

Prenatal ontogenesis of pro-opiomelanocortin in the mouse central nervous system and pituitary gland: an in situ hybridization and immunocytochemical study.

Pro-opiomelanocortin (POMC) mRNA detected by in situ hybridization and POMC/ACTH (adrenocorticotropin)-containing neurons detected by immunocytochemistry were first observed in the presumptive arcuate nucleus of embryonic mouse brain on gestational day 10.5 (E10.5). Immunostained fibers were also evident on E10.5 in the lateral and dorsal diencephalon. In these areas, a dense network of processes developed by E11.5 and extended into the mesencephalon. Fibers were detected in the myelencephalon at this stage and a day later (E12.5) in the spinal cord. Adult-like patterns of POMC/ACTH fibers were established in the diencephalon, mesencephalon, metencephalon and the myelencephalon between E13.5 and E15.5. POMC-expressing cells in the anterior and intermediate lobes of the pituitary gland appeared on E12.5 and E14.5, respectively. The early expression of POMC and the rapid establishment of dense fiber tracts in the brain is consistent with a role for POMC-derived peptides in the development of the central nervous system.

Animals↗

PubMed1990

Expression of cellular retinoic acid binding protein in the developing nervous system of mouse embryo.

The expression of cellular retinoic acid binding protein, CRABP, in developing mouse embryos was immunohistochemically analyzed. Differentiating young neurons and neuronal fibers in the myelencephalon, metencephalon, mesencephalon and spinal cord in 10.5- and 12.5-day embryos showed intense expression of CRABP, but undifferentiated cells in the neural tube did not. Neural tissue in 16.5-day embryos expressed less amount of binding protein than the tissues of the younger stages. These expressions of CRABP suggest that retinoic acid participates in neurogenesis at early developmental stages via expression of cellular retinoic acid binding protein.

Animals↗

PubMed1984

Ontogenesis of the central serotonin neuron system of the rat--an immunohistochemical study.

The peroxidase-antiperoxidase technique was used to study the ontogenesis of serotonin-containing neurons in fetal, neonatal and adult rats. Serotonin-containing neurons were first detected in a rat embryo of crown-rump length (CRL) 5 mm, bilaterally distributed in the ventral metencephalon near the isthmus rhombencephali. Serotonin fibers were first detected in CRL 6 mm embryos. There was a rapid increase in serotonin-immunoreactive neurons of embryos of 7-8 mm CRL. Serotonin neurons appeared initially as independent, bilateral groups of neurons, but as early as CRL 16 mm, the adult mid-line distribution was present, while the neurons that occurred as single groups in the adult already existed as single groups or at least were only partially connected across the mid-line. A continuous distribution of serotonin neurons was observed in the mesencephalic and pontine reticular formation from CRL 13 mm to the adult stage. It is suggested that the rapid increase in serotonin neurons at 7 and 8 mm CRL is associated with the completion of mitosis which occurs at this time.

Animals↗

PubMed1991

Expression of the homeobox engrailed gene during the embryonic development of the nervous system of the trout (Salmo fario L.).

The expression of the engrailed homeobox gene during trout embryogenesis has been examined using immunohistochemistry and the monoclonal antibody 'Mab 4D9'. Engrailed has been suggested to play an important role during development by controlling position-specific characteristics in the CNS of the early embryo. In the present study we have analyzed the expression of engrailed at 5 stages of embryonic development of the trout (Salmo fario L.). The earliest stage analyzed was when the optic vesicles appear. Engrailed was then expressed in the posterior mesencephalon and anterior metencephalon, in a caudorostrally decreasing gradient. As the embryo develops, the pattern of the engrailed expression increases in spatial complexity. Thus, in the later stages of development, just before hatching, engrailed was found in hypothalamic areas, the germinative matrix layer of the cerebellum, the mesencephalic tegmentum, the caudal optic tectum and in the area of the trigeminal motor nucleus. This is similar to the distribution of engrailed in embryos of amphibians, birds and mammals.

Animals↗

PubMed1994

Tropism of serotonergic neurons towards glial targets in the rat ependyma.

During development, recognition mechanisms between neurons and their targets are necessary for the formation of the neuronal network. Neural connections are synaptic or non-junctional. Both types of communication can be found between neurons and glial elements in the periventricular walls. Serotonergic fibers form synaptic contacts on the specialized ependymocytes of the subcommissural organ, a structure which forms the roof of the third ventricle at its junction with the aqueduct. A network of non-junctional fibers containing both GABA and serotonin spread between the cilia of the classical ependymocytes in the ventricles. These anatomical, morphological and biochemical features suggest a tropism and specific recognition mechanisms between glial elements and serotonergic neurons. This hypothesis can be tested by the study of the innervation of the subcommissural organ and the classical ependyma by grafted embryonic neurons after a chemical destruction of the serotonergic endogenous innervation. Solid implants or cell suspensions prepared from embryonic metencephalon were transplanted to either the third ventricle or the periventricular gray matter in 5,7-dihydroxytryptamine denervated rats. Grafted serotonergic neurons were able to reinnervate the classical ependyma and the subcommissural organ. The fibers forming the supraependymal plexus were non-junctional and contained both serotonin and GABA while those innervating the subcommissural organ formed synaptic contacts and contained only serotonin. The signals capable of inducing the ependymal innervation were specific for serotonergic neurons since catecholaminergic neurons present in the grafts were unable to innervate either classical or specialized ependymocytes. These results demonstrate that glial cells are targets for serotonergic neurons and that the morphological and biochemical characteristics of the serotonergic innervation are closely related to the target cell phenotype.

5,7-Dihydroxytryptamine↗

PubMed1992

Concept of the development of the mammalian cerebellum based on physical rotation forces.

In pre-mammalian forms the cerebellum (rhombencephalon) has no rhombic lip and it develops in the median region between the two auricles above the front end of the fourth ventricle. In mammals, cells in the superior rhombic lip and dorsal part of the dorsal lamina of the metencephalon are said to proliferate to form two rounded swellings, the rudiments of the cerebellum. This assumption does not explain many peculiarities of the mammalian cerebellum, 11 of which have been described. The crux of the present hypothesis is that the mammalian cerebellar hemispheres and vermis develop from the median cerebellar element seen in the pre-mammalian forms and that the vermis does not develop as a confluence of the two hemispheric tissues.

Animals↗