bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distribution of zebrin II in the gigantocerebellum of the mormyrid fish Gnathonemus petersii compared with other teleosts
Authors: Meek J. , Hafmans T. G. M. , Maler L. , Hawkes R. 
Published: January 2005

AbstractImmunocytochemistry has demonstrated unexpected heterogeneity among cerebellar Purkinje cells. For example, monoclonal antibody Mab anti‐zebrin II reveals parasagittal bands of immunoreactive Purkinje cells in the mammalian cerebellum, but reveals a non‐sagittal cerebellar compartmentation pattern in goldfish and gymnotiform fish. The present paper investigates the cerebellar compartmentation pattern, as reflected in the zebrin II distribution, in two other teleosts, the electric mormyrid fish Gnathonemus petersii with its large and regularly built gigantocerebellum, and the electrosensory osteoglossomorph teleost Xenomystis nigri, by‐using light as well as electron microscopic immunohistochemical techniques.Zebrin II is expressed only in Purkinje cells, where it is present in the cytoplasm of all neuronal compartments, including spines, distal and proximal dendrites, the cell body, and the initial part, as well as terminal boutons of the axon. Other types of cerebellar neurons, including the eurydendroid projection neurons, are zebrin II‐negative. In Gnathonemus, zebrin II‐positive Purkinje cells are present in the large caudolateral part of the valvula, in lobes C2, C3, and C4 of the corpus, and in the anterior as well as the posterior part of the caudal cerebellar lobe. Zebrin II‐negative Purkinje cells are present in a continuous region encompassing the rostromedial part of the valvula, the lobus transitorius, lobe C1 and the ventral part of lobe C2, and in a small, lateral zone of the posterior part of the caudal lobe. In Xenomystis, all Purkinje cells, including those in the medial valvula and the posterior part of the caudal lobe, appear to react with mab anti‐zebrin II. This more widespread distribution may be due to the presence of a second antigenic polypeptide in this species.On the basis of the present findings, it is concluded that the mormyrid lobus transitorius, lobe C1, and the ventral part of lobe C2 probably belong to the valvula, while the corpus is restricted to the dorsal part of lobe C2, lobe C3, and lobe C4. The functional significance of zebrin II expression for different subsets of teleostean Purkinje cells remains unclear, since comparisons of different teleosts reveal no general correlation with particular afferent or efferent connections, nor with special morphological features such as a dendritic palisade pattern or different arrangements of the Purkinje cell bodies. A comparison between mammals and teleosts suggests that a distinct parasagittal cerebellar zonation in teleosts is absent, and the major part of the teleostean cerebellum may be considered as a single (midsagittal) cerebellar zone, with about the same width as one mammalian parasagittal zone.
Small‐field neurons associated with oculomotor control in muscoid flies: Cellular organization in the lobula plate
Authors: Strausfeld Nicholas J. , Gilbert Cole 
Published: January 2005

AbstractIn muscoid flies, the lobula plate is the last station in the optic lobes for processing spectrally independent information from retinotopic afferents. Until recently, it was thought that most lobula plate neurons were color‐insensitive wide‐field tangential neurons that respond to direction‐specific motion. It has been suggested that certain of these supply inputs to premotor descending neurons involved in the control of flight and head movements. The present account describes a Golgi and cobalt‐silver analysis that reports evidence for additional lobula plate outputs, which are numerically complex and structurally elaborate. Beneath a retina with approximately 4,000 ommatidia, each of at least 15 populations of morphologically distinct small‐field neurons comprises approximately 110–440 elements that contribute to an isomorphic neural assembly subtending the whole retina. Morphologically small‐field efferents form three classes according to the origin of their axons and their arborization in the lobula plate and lobula. Neurons arising from the lobula plate, or shared by it and the lobula, visit dorsal descending neurons supplying the neck and flight motor in contrast to output neurons from the lobula, which project to ventral descending neurons supplying leg motor neuropils. The possible functional significance of small‐field lobula plate outputs onto descending neurons in the dorsal deutocerebrum is discussed.
Morphology of single medial vestibulospinal tract axons in the upper cervical spinal cord of the cat
Authors: Shinoda Yoshikazu , Ohgaki Tohru , Sugiuchi Yuriko , Futami Takahiro 
Published: January 2005

AbstractThe morphology of single medial Vestibulospinal tract (MVST) axons was investigated by iontophoretic injection of horseradish peroxidase into single axons at the upper cervical cord in pentobarbital‐anesthetized cats. MVST axons were identified by their monosynaptic responses to stimulation of the vestibular nerve and their direct responses to stimulation of the medial longitudinal fusciculus (MLF). Reconstructions of the axonal trajectory were made from 22 uncrossed and 19 crossed MVST axons at C1–C4. MVST axons ran in the ventral funiculus and gave rise to multiple axon collaterals to the upper cervical gray matter at different segments. These axons could be traced over the distance of 2.5–15.3 mm. Within these lengths, up to 9 axon collaterals were identified per axon (mean = s.d., 3.3 = 2.0, n = 41). Axon collaterals ramified in the gray matter several times and spread in a delta‐like manner in both the transverse and horizontal planes. There were usually gaps free from terminal arborizations between adjacent axon collaterals, since the rostrocaudal extension of individual axon collaterals (mean = 820 μm) was very much limited in contrast to wide intercollateral intervals (mean = 1,510 μm). Axon terminals were distributed mainly in laminae IX, VIII, and VII, and sometimes in laminae VI–IV. Most abundant terminals were observed in lamina IX, including the ventromedial (VM), the spinal accessory (SA) nuclei and the nucleus dorsomedial to the VM nucleus (DM nucleus). A majority of individual axon collaterals provided some terminal branches to at least one of the above three motor nuclei. Axon collaterals projecting to laminae VIII–VI without terminals in the motor nuclei were rarely observed. Individual MVST axons had a preferential terminal distribution in each motor nucleus, but all three motor nuclei were covered by axon terminals of an ensemble of all MVST axons, indicating that all neck muscles innervated by these three motor nuclei are influenced by vestibular inputs through MVST axons. Most collaterals from a single axon produced circumscribed terminal arborizations in one or two common areas in the transverse plane (mainly in lamina IX) that were in line with one another in the longitudinal axis of the cord. This longitudinal arrangement of discontinuous terminal arborizations in lamina IX from a single axon may correspond to a continuous sagittal column of motoneurons for a particular muscle. In addition, virtually all well‐stained MVST axons, both crossed and uncrossed, terminated in more than one motor nucleus of neck muscles in different combinations; single MVST axons were seen to project to the VM and SA nuclei, to the VM and DM nuclei, to the DM and SA nuclei, or to all three nuclei. Therefore, this result indicates that different sets of neck muscles innervated by a single MVST axon may constitute a functional synergy which participates in eliciting proper compensatory head movement.
Competition between an aphakic and an occluded eye for territory in striate cortex of developing rhesus monkeys: Cytochrome oxidase histochemistry in layer 4C
Authors: Tigges Margarete , Boothe Ronald G. , Tigges Johannes , Wilson James R. 
Published: January 2005

AbstractMonkey models were used to examine the effects of competition for cortical territory between two eyes which were deprived simultaneously, but each eye experienced a different type of deprivation. We wanted to determine whether, under this condition of binocular unequal deprivation, the postnatal process of segregation into ocular dominance columns proceeds according to the same rules as those that apply to competition between a deprived and an undeprived fellow eye. Our models involved surgical removal of the natural lens from one eye in newborn rhesus monkeys. The resulting aphakia was corrected optically to a near point with extended‐wear contact lenses. The fellow eyes were either left unmanipulated or occluded with opaque contact lenses for varying periods during the day. At the end of the rearing period, some monkeys from each experimental group had either one eye enucleated or sustained injury to the retinal ganglion cells of one eye. The histochemical reaction for cytochrome oxidase was used to reveal the widths of ocular dominance columns in layer 4C of striate cortex in these monkeys. Under all experimental conditions, the axons related to the two eyes occupied segregated fields. The amount of cortical territory related to the aphakic, optically corrected eye depended on the manipulations of the fellow eye. In competition with an unmanipulated fellow eye, the aphakic eye's territory was greatly reduced. In competition with a part‐time occluded eye, its territory was reduced to a lesser degree, depending on the duration of the occlusion. In competition with a continuously occluded eye, however, the space related to the aphakic, optically corrected eye was slightly greater than that related to the occluded eye. Since neither the aphakic nor the continuously occluded eye receives normal visual input, they are both impaired. Therefore, they may compete on an almost equal basis for synaptic territory in layer 4C of striate cortex. Moreover, it is likely that activities originating in the aphakic and the continuously occluded eye are asynchronous, and that this condition is sufficient to drive the postnatal segregation of inputs from the two deprived eyes.
Dorsal root ganglion neurons projecting to the dorsal column nuclei of rats
Authors: Giuffrida R. , Rustioni A. 
Published: January 2005

AbstractDorsal root ganglion (DRG) neurons may give origin to ascending branches that terminate in the dorsal column nuclei (DCN); uncertainties still exist with regard to the proportion of these neurons in different DRGs and to the type of these neurons. The percentage and size of neurons that project to the DCN were determined in a large number of DRGs by means of the retrograde transport of colloidal gold‐labeled wheat germ agglutinin conjugated to enzymatically inactive horseradish peroxidase (WGAapoHRP‐AU). A total of 16,239 neurons was tallied in 80 DRGs from nine rats; 3,240 (20%) of these were retrogradely labeled by the tracer injected in the DCN. Percentages of DCN projecting neurons vary considerably at different segmental levels: they are higher in cervical (up to 63%) than in thoracic (up to 31% for T1, up to 12% for thoracic DRGs below T1) or lumbar DRGs (up to 15%). At cervical levels highest percentages were encountered in C6, C7, and C8 and lowest percentages in C2‐C4. At lumbar levels highest percentages were encountered in L4 and lowest in L1 and L6. When considering the soma size of DRG neurons it appears that: (1) there are more large cells, labeled and unlabeled, at cervical (38%) than at lumbar levels (30%) and more at lumbar than at thoracic levels (23%); (2) at every level, most labeled, i.e., projecting, neurons are large; and (3) DRGs with the highest proportions of large vs. small cells contain the highest percentages of DCN projecting neurons.These results represent the first attempt at establishing the percentages and soma size of DCN projecting neurons from a large number of DRGs and at comparing the contribution to these nuclei from cervical, thoracic, and lumbar DRGs. Some of the differences in the ratio of projecting neurons at different levels may be explained on the basis of well‐known anatomical features, e.g., the projections to the Clarke's column of many DRG neurons in lumbar ganglia. The contribution of virtually exclusively large DRG neurons to the DCN, suggested by indirect or incomplete evidence, is demonstrated by the present retrograde labeling and soma size measurements. The results relate to the functional component of peripheral receptors that relay their input via the dorsal columns and do not seem to support a recent suggestion that a sizeable fraction of unmyelinated primary afferents ascend in the dorsal columns to terminate in the DCN.
Neuropeptide Y (NPY) and C‐flanking peptide of NPY in the pineal gland of normal and ganglionectomized sheep
Authors: Cozzi Bruno , Mikkelsen Jens D. , Ravault Jean‐Paul , Møller Morten 
Published: January 2005

AbstractThe present immunohistochemical study describes the presence and distribution of nerve fibers containing neuropeptide Y (NPY), and C‐Flanking Peptide Of NPY (CPON) in the pineal gland of the sheep. Nerve fibers were detected by using a series of antisera directed against NPY or against CPON. Many positive immunoreactive nerve fibers were identified in the pial capsule of the pineal, in connective septae and in the parenchyma between pinealocytes. The intraparenchymal fibers were particularly evident and created an extensive network throughout the gland. Nerve fibers immunoreactive for all the peptides were also observed in the posterior commissure and in the stria medullaris thalami. No NPY‐ or CPON‐positive neurons were found in the pineal gland.In order to study the site of origin of NPY‐ and CPON‐immunoreactive nerve fibers, the superior cervical ganglia were bilaterally removed in a series of animals. Sympathetic denervation was checked by using an antiserum against tyrosine hydroxylase (TH). Nearly all TH‐immunoreactive elements disappeared in the pineal glands of animals sacrificed 15 days after surgery. Also the density of NPY‐ and CPON‐immunoreactive nerve fibers decreased in the animals after the ganglionectomy. However, a number of nerve fibers still remained in the gland. These data indicate that some NPY‐ and CPON‐immunoreactive nerve fibers of the sheep pineal gland derive from an extrasympathetic origin. The very dense innervation of the sheep pineal gland with nerve fibers containing NPY and CPON strongly indicates a functional role for this family of peptides in the pineal gland of this species.
Localization of FMRF amide‐like peptides in Caenorhabditis elegans
Authors: Schinkmann K. , Li C. 
Published: January 2005

AbstractThe neuropeptide FMRFamide (Phe‐Met‐Arg‐Phe‐NH2) is a member of a large family of related peptides that have been found throughout the animal kingdom. By using an antiserum specific for the Arg‐Phe‐NH2 moiety, we have found that about 10% of the neurons in the nematode Caenorhabditis elegans are immunoreactive. Most of these neurons, which include sensory, motor, and interneurons, were identified on the basis of their number, position, and projection pattern and by analysis of characterized mutants. Neurons that were immunoreactive in hermaphrodite animals were generally also found in males, but each sex had, in addition, sex‐specific immunoreactive cells. Staining of hermaphrodite animals from different larval stages suggests that the onset of FMRFamide‐like expression is differentially regulated among the cells. We have found a possible neuromodulatory role for the related peptide FLRFamide (Phe‐Leu‐Arg‐Phe‐NH2). In an egg‐laying assay, FLRFamide by itself was not active but could potentiate a serotonin effect. The FMRFamide‐like immunoreactivity was also used as a marker to examine the differentiation of cells that normally undergo programmed cell death. Cells that are destined to die in the Pn.a lineages appear to differentiate and adopt the fate of lineally equivalent cells before cell death.
Mapping of angiotensin II receptor subtype heterogeneity in rat brain
Authors: Song Keifu , Allen Andrew M. , Paxinos George , Mendelsohn Frederick A. O. 
Published: January 2005

AbstractAngiotensin II (Ang II) exerts a number of central actions on fluid and electrolyte homeostasis, autonomic activity, and neuroendocrine regulation. In order to evaluate likely sites where these actions are mediated, Ang II receptor binding was localized in rat brain by in vitro autoradiography with the aid of the antagonist analogue l25I‐[Sar1, Ile8]Ang II. Two subtypes of Ang II receptor have been identified using recently developed peptide and nonpeptide antagonists. In the periphery, the receptor subtypes differ in distribution, second messenger coupling, and function. Brain Ang II receptor subtypes were therefore differentiated into AT‐1 (type I) and AT‐2 (type II) subtypes by using unlabelled nonpeptide antagonists specific for the two Ang II subtypes.AT‐1 binding was determined to be that inhibited by Dup 753 (10 μM) and AT‐2 binding to be that inhibited by PD 123177 (10 μM). The reducing agent dithiothreitol (DTT) decreased binding to AT‐1 receptors and enhanced binding to AT‐2 receptors.Many brain structures, such as the vascular organ of the lamina terminalis, subfornical organ, median preoptic nucleus, area postrema, nucleus of the solitary tract, and dorsal motor nucleus of the vagus, which are known to be related to the central actions of Ang II, contain exclusively AT‐1 Ang II receptors.By contrast, the locus coeruleus, ventral and dorsal parts of lateral septum, superior colliculus and subthalamic nucleus, many nuclei of the thalamus, and nuclei of the inferior olive contain predominantly AT‐2 Ang II receptors.The detailed binding characteristics of each subtype were determined by competition studies with a series of analogues of angiotensin and antagonists. The pharmacological specificity obtained in rat superior colliculus and the nucleus of the solitary tract agreed well with published data on AT‐1 and AT‐2 receptors, respectively.There was a high degree of correlation between the distribution of Ang II binding sites with published data on Ang II‐immunoreactive fields and on the sites of Ang II‐responsive neurons.The present study also reveals pharmacological heterogeneity of brain Ang II receptors. The subtype‐specific receptor mapping described here is relevant to understanding the role of angiotensin peptides in the central nervous system and newly discovered central actions of nonpeptide Ang II receptor antagonists.
Organization of parabrachial nucleus efferents to the thalamus and amygdala in the golden hamster
Authors: Halsell Christopher B. 
Published: January 2005

AbstractWhile gustation in the hamster has been extensively studied at the behavioral and physiological level, very little is known about the central anatomy of the taste system. The purpose of this study was to trace the connections of the parabrachial nucleus (PBN) in the golden Syrian hamster (Mesocricetus auratus) using wheat germ agglutinin‐conjugated horseradish peroxidase. The PBN is the site of the second central synapse for the ascending gustatory system and receives taste afferents from the nucleus of the solitary tract. Following large injections into the PBN, anterogradely transported label was seen in the lateral hypothalamus dorsal thalamus, bed nucleus of the stria terminalis, and amygdala. The anatomy of the two primary targets, the ventral posteromedial thalamus and central nucleus of the amygdala, is described based on Nissl‐stained material, and acetylcholinesterase and NADH dehydrogenase histochemistry. Injections into these two regions revealed different patterns of efferents within the PBN. Following injections into the thalamus, retrogradely labelled cell bodies were distributed throughout the PBN subdivisions bilaterally, but concentrated in the central medial (CM) and external lateral (EL) subdivisions. Following injections into the amygdala, retrogradely labelled cell bodies were primarily in the ipsilateral PBN EL, while anterogradely transported label was distributed throughout much of the ipsilateral PBN. The majority of CM efferents projecting to the thalamus were elongate cells, whereas the majority of CM efferents to the amygdala were round‐oval cells. These results indicate that the ascending central gustatory system changes from a serial pathway (nucleus of the solitary tract‐PBN) to a parallel organization consisting of two major projections, the parabrachio‐thalamo‐cortical and parabrachio‐amygdaloid pathways.
Migration of astrocytes transplanted to the midbrain of neonatal rats
Authors: Zhou Hai Feng , Lund Raymond D. 
Published: January 2005

AbstractPrevious studies have indicated that transplanted astrocytes are able to survive, express glial fibrillary acidic protein (GFAP), and migrate in the host brain, and that the pattern and speed of astrocyte migration is largely determined by the location of the graft. We examine here the pattern of astrocyte migration in the midbrain by transplanting CD‐1 mouse corpus callosum (P2–3) into the midbrain of neonatal rats. The location of the grafts and the distribution of donor astrocytes were assessed by using a monoclonal antibody (anti‐M2) specific for mouse astrocytes. A characteristic donor astrocyte distribution was seen. The highest density of cells was in the region of the substantia nigra (SN); lower numbers were found in the medial geniculate nucleus (MGN). Donor astrocytes were also found in the superior colliculus (SC) and central gray region, but only when the body of a graft was located nearby. [3H]thymidine studies showed that the concentrations of donor astrocytes in the SN were not the result of high levels of mitotic activity: all indications were that the proportion of dividing donor cells closely matched that of host glia. The pattern of astrocyte migration in the midbrain did not follow the course established by radial glia and was not influenced by axonal degeneration in the SC after removal of eyes. Moreover, donor cells failed to migrate along the course of axonal outgrowth from co‐grafted retinae. Reciprocally, axonal elongation from retinal grafts did not follow the pathway of astrocyte migration, thus suggesting that astrocyte migration and neuronal outgrowth follow different cues.