bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of choline acetyltransferase and nerve growth factor receptor within hypoglossal motoneurons following nerve injury
Authors: Armstrong David M. , Brady Roseann , Hersh Louis B. , Hayes Robert C. , Wiley Ronald G.
Published: January 2005

In the present study we employed light microscopic immunocytochemical techniques in order to investigate the temporal response of choline acetyltransferase (ChAT) and nerve growth factor receptor (NGFr) within hypoglossal motoneurons following unilateral transection or crushing of the XII nerve or after intraneural injections of ricin into the nerve. In control rats (i.e., sham operated) virtually all the motoneurons of the XII nucleus displayed intense immunolabeling for ChAT and were devoid of NGFr immunoreactivity. As early as 3 days post‐operative the intensity and the number of ChAT‐labeled neurons were reduced on the axotomized side compared to the non‐lesioned side. This decrease was maximal approximately two weeks post‐operative when virtually no ChAT‐labeled cells were present on the lesioned side. In contrast, no loss of hypoglossal neurons was found using Nissl stains. This absence of ChAT immunolabeling persisted for several days, yet by 30 days many of the motoneurons had begun to re‐express the enzyme.

In contrast to the decrease in ChAT immunoreactivity, transection of the XII nerve also resulted in the expression of NGFr immunoreactivity within the lesioned motoneurons. This response was detected as early as one day post‐operatively and continued throughout all time points thus far examined including times after many of the motoneurons had begun to re‐express ChAT.

Crushing of the XII nerve effected the expression of ChAT and NGFr in a manner comparable to, yet less intense than, that observed following transection.

Ricin injected directly into the XII nerve resulted in the loss of hypoglossal motoneurons as demonstrated both in immunohistochemical and Nissl‐stained tissue preparations. The cell loss was readily apparent 3 days post‐operatively, and ChAT immunoreactivity permanently disappeared. NGFr immunolabeling was seen only in scattered surviving neurons but not in ricin poisoned cells.

The possible mechanisms underlying the differential expression of ChAT and NGFr are discussed.
Source of sexually dimorphic galanin‐like immunoreactive projections in the teleost fish Poecilia latipinna
Authors: Cornbrooks Ellen B. , Parsons Rodney L.
Published: January 2005

A galaninlike peptide has a sexually dimorphic distribution in the teleost fish, the sailfin molly. An extensive system of galanin‐like immunoreactive (GAL‐LI) fibers has been described in the brainstem and spinal cord of the male molly, which is absent in the female (Cornbrooks and Parsons, companion paper). As GAL‐LI in the mammalian spinal cord has been localized to neurons of origin in the dorsal root ganglia and dorsal and ventral horns, the present study was undertaken to determine whether the sexually dimorphic GAL‐LI in the male molly may originate in part from corresponding sources in this species.

Colchicine treatments of the spinal cord and dorsal root ganglia did not result in GAL‐LI staining in neuronal somata in these regions. Following complete transection of the spinal cord and at any level of the spinal cord, there was a complete absence of GAL‐LI caudal to the lesion site. In fish that received unilateral spinal transection, there was a loss of GAL‐LI ipsilateral and caudal to the lesion. Finally, in fish that received lesions in the rostral hypothalamus, there was a complete loss of GAL‐LI in the sexually dimorphic fiber system in the brainstem and spinal cord, but not in non‐dimorphic GAL‐LI regions of the brainstem. Thus the sexually dimorphic fiber system in the male molly may originate in neurons of the preoptic nucleus that are sexually dimorphic for a GAL‐LI peptide. This preoptico‐spinal pathway may mediate sex‐specific behaviors in this species.
Retinal afferents to the tectum opticum and the nucleus opticus principalis thalami in the pigeon
Authors: Remy Monika , Güntürkün Onur
Published: January 2005

The retinal afferents of the tectum opticum and the n. opticus principalis thalami (OPT) were studied with fluorescent tracers in pigeons. Injections into the tectum opticum revealed topographically related areas of high density labelling in the contralateral retina. In these areas up to 15,000 cells/mm2 were labelled. After tectal injections the soma sizes of labelled retinal ganglion cells in the area centralis ranged from 5 to 23 μm with a mean of 7.5 μm. Afferents from the ipsilateral retina could not be demonstrated. Injections into the OPT labelled neurons throughout the retina without a clear topographical relation to the locus of injection. The density never exceeded 150 cells per mm2. The soma size range was 8 to 35 μm with a mean of 14.6 μm. Independently of the injection area within the OPT, the red field in the dorsotemporal retina was always extremely sparsely labelled. The number of labelled ganglion cells in this area never exceeded 25 neurons/mm2. After OPT injections the average density of labelling per unit area was six times higher in the yellow than in the red field. The results confirm previous reports of a massive and topographically organized retinal projection onto the optic tectum. The projection onto the OPT was clearly smaller and with the retrograde tracing techniques in use, an orderly topography has not been demonstrated. The paucity of red field projections onto the OPT suggests that the role of the thalamofugal pathway in binocular integration is very limited.
Histochemical demonstration of zinc in the hippocampal region of the domestic pig: II. Subiculum and hippocampus
Authors: Holm Ida E. , Geneser Finn A.
Published: January 2005

The distribution of zinc has been described in two areas of the hippocampal region of the domestic pig, viz., the subiculum and the hippocampus. Zinc was demonstrated histochemically according to the Neo‐Timm method, a modification of the sulphide‐silver procedure. In each of the examined areas the staining displayed a distinctly stratified pattern which has been compared in detail to fields and layers defined on the basis of cyto‐ and fibroarchitecture, resulting in a combined chemo‐ and cytoarchitectonic map. Most of the staining was confined to the neuropil, but a considerable number of stained nerve cell bodies were seen in both the subiculum and the hippocampus.

In the subiculum, the plexiform layer was divided into a superficial, weakly stained subzone and a deep, better stained subzone. The cell layer was generally well stained, but displayed a complex staining pattern with differences in staining intensity of both the cell bodies and neuropil. In regio superior of the hippocampus, the stratum moleculare appeared weakly stained, with the exception of a tapering process of more darkly stained tissue projecting from the plexiform layer of the subiculum into the deepest part of the layer. Stratum radiatum and the superficial subzone of stratum oriens showed a weak staining intensity, contrasting to the relatively darkly stained pyramidal cell layer and the intensely stained deep subzone of stratum oriens. In regio inferior, the stratum moleculare was divided into a moderately stained superficial part and an unstained deep part. Stratum radiatum and stratum oriens both appeared weakly stained. The layer of mossy fibers was very intensely stained and appeared almost homogeneously black in its main suprapyramidal part, whereas the infrapyramidal part was looser in character. The pyramidal cell layer was darker than in regio superior.

The distribution of zinc in the pig was compared with that in the guinea pig and rat, described previously. The staining pattern is fundamentally similar in all three species, though notable species‐specific traits do exist.
Synaptic organization of columnar elements in the lamina of the wild type in Drosophila melanogaster
Authors: Meinertzhagen I. A. , O'Neil S. D.
Published: January 2005

The synaptic connections within the lamina, the first of the optic neuropiles underlying the insect's compound eye, have been little studied in Drosophila melanogaster until now, despite the genetic advantages of this animal. Here we report the reconstruction through its entire depth of one of the lamina modules, or cartridges, of a female wild‐type Drosophila, for which a series of EM cross sections was analysed at levels extending from the retinal basement membrane to the first optic chiasma. A complete, comprehensive catalogue of the synaptic connections of all columnar elements has been compiled from this single series, confirmed from comparisons with less completely photographed cartridges. Combinations of the 12 types of cartridge neurons form divergent multiple‐contact synapses (dyads, triads, and tetrads) throughout the lamina's depth. These 12 neuron types include 11 narrow‐field elements (one class of receptor terminal, R1–R6, providing input to the cartridge; two types of long visual fiber from the ommatidium, R7 and R8; five types of monopolar cell, L1–5; and three types of medulla cell–two centrifugal neurons C2 and C3, and a third, T1) as well as a wide‐field intrinsic or amacrine cell. Connections within the lamina formed by L4 from two adjacent cartridges (posterodorsal and posteroventral) contribute to the matrix of connections. In addition, connections of at least one other wide‐field element have also been incorporated.
Inventory and distribution of synapses of identified uniglomerular projection neurons in the antennal lobe of Periplaneta americana
Authors: Malun Dagmar
Published: January 2005

Uniglomerular projection neurons in the antennal lobe of Periplaneta americana, the axons of which connect the lobe to the protocerebrum, were labeled by intracellular injection of Lucifer Yellow or biocytin. The fine structure of individual neurons within the antennal lobe was examined after the injected substances had been converted (by immunohistochemical or histochemical treatment) to electron microscopically visible reaction products. Seven projection neurons were investigated, including attractant neurons, with dendritic arbors in the macroglomerulus, and projection neurons of normal‐sized glomeruli. From reconstructions of thin serial sections and examination of additional processes present at various places in the arborization regions, the distribution of synapses within the glomeruli was inferred.

Although the projection neurons differ from one another in their glomerular arborization patterns, they are very similar in the spatial segregation of their input and output synapses within the arborization. Output synapses are found on the thick part of the fiber near its site of entry into the glomerulus, as well as in regions within the glomerulus where the neuron has begun to ramify into thinner fibers. In the latter regions, the many output synapses are accompanied by occasional input synapses; hence these are regarded as transitional regions. At the terminal arbors only input synapses were found. This suggests that neurons with dense terminal arborizations receive particularly numerous inputs in these regions.

The large number of input synapses reflects the high degree of convergence of afferents onto projection neurons previously demonstrated physiologically. However, the presence of numerous output synapses indicates that projection neurons not only transport sensory information into the protocerebrum but are also a major component of the neuronal circuitry within the antennal lobe.
Distribution of estrogen receptor‐immunoreactive cells in the forebrain of the female guinea pig
Authors: Doncarlos Lydia L. , Monroy E. , Morrell J. I.
Published: January 2005

We mapped the distribution of estrogen receptor‐containing cells in the forebrain of the adult female guinea pig. Cellular estrogen receptor content was detected using monoclonal antibody H222, directed against the estrogen receptor, and the avidin‐biotin method with nickel‐intensified diaminobenzidine as the chromagen. A complete set of deletion, titration, and adsorption controls established the specificity of the staining. The most dense collections of estrogen receptor‐immunoreactive cells were found in medial preoptic, medial hypothalamic, and limbic nuclei (amygdala, bed nucleus of the stria terminals, lateral septum). Numerous estrogen receptor‐immunoreactive cells were also found in additional, specific subregions of the remainder of the preoptic area, hypothalamus, and limbic system, and also in the midbrain (central gray). Elsewhere, estrogen receptor‐immunoreactive cells were present in smaller numbers or were absent. This map confirms and extends previous maps based on estrogen binding. The majority of estrogen receptor‐immunoreactive cells are found in areas known to be involved in some aspect of reproduction. In addition, many estrogen receptor‐immunoreactive cells are found in areas not typically considered to have a primary role in reproductive behavior or neuroendocrine function.
Orientation discrimination in the cat: Its cortical locus. I. Areas 17 and 18
Authors: Vandenbussche E. , Sprague J. M. , De Weerd P. , Orban G. A.
Published: January 2005

An elementary unit of visual pattern and form perception is thought to be the orientation of edges; this element has been studied extensively by neurophysiologists using oriented line segments or bars. These same stimuli have been used in the present study to measure threshold discriminations in cats before and after cortical lesions of areas 17 and/or 18. Control experiments showed that the discriminations were made by using a single cue, orientation, and that other stimulus parameters, width, length and contrast of the bar, were optimized.

The extent of the lesions was evaluated anatomically from cell and fiber stained sections through cortex and thalamus, matched to retinotopic maps of Tusa et al. (Cortical Sensory Organization, Vol. 2, Humana Press, pp. 1–31, '81) and Sanderson (Journal of Comparative Neurology 143:101–118, '71), and physiologically from visual field position of receptive fields of cells recorded in areas neighboring the lesions.

Lesions involving area 17 and large parts of area 18 produced a marked deficit in orientation discrimination which included a loss in retention, and after retraining a substantial increase in thresholds for up to 3 years when tested with long bars. There was no recovery of discrimination when the animals were tested with short bars.

Lesions which involved area 17 plus small parts of 18, or lesions of areas 18 and 19, produced no retention deficit and resulted in an increase in thresholds only at low contrast and narrow width.

These experiments revealed an excellent correlation between lesion locus and size and behavioral deficit. They indicate that the cortical representation of bar orientation used for discrimination is distributed within and across areas 17 and 18. The spread of the distribution depends on other stimulus parameters such as bar width and length. Furthermore the experiments show that neither the most narrowly tuned cells nor the X‐cell system is required for fine orientation discrimination of a long bar.
Anatomy and physiology of spiking local and intersegmental interneurons in the median neuroblast lineage of the grasshopper
Authors: Thompson Karen J. , Siegler Melody V. S.
Published: January 2005

The range of anatomical and physiological properties in the adult progeny of an identified neuroblast was investigated. Some 80–90 adult neurons constitute the dorsal unpaired median (DUM) group of the grasshopper metathoracic ganglion. Within the group are efferent, octopaminergic neurons with large cell bodies and overshooting action potentials. Our objective was to determine the properties of the neurons with small cell bodies that make up the majority of the clone, some 60–70 neurons, about which scant information was available. The small DUM neurons have cell body diameters of 10–20 μm and stain with antibodies to GABA (Thompson and Siegler, '89: Proc. Soc. Neurosci. 15:1296 (abstr.); Witten and Truman, '89: Proc. Soc. Neurosci. 15:365 (abstr.)). By employing intracellular electrophysiological and morphological techniques, we have established that the small DUM neurons are spiking interneurons, expressing passively conducted action potentials in the cell body. They fall into two basic classes: local interneurons with bilateral branches in the auditory neuropiles, and intersegmental interneurons with bilateral branches widespread in the metathoracic ganglion and axons traveling in both anterior connectives. The local interneurons typically respond to sound, whereas the intersegmental interneurons selectively respond to wind on the head or to generalized movements by the animal. Primary neurites of small and large DUM neurons enter the neuropil in a bundle, but the neurites of DUM interneurons are more posterior and have a separate trajectory from those of the efferent DUM neurons once in the ganglion core. A model is presented for the sequential development of efferent, local, and intersegmental DUM neurons from the median neuroblast.
Junctional specializations between growth cones and glia in the developing rat pyramidal tract: Synapse‐like contacts and invaginations
Authors: Gorgels T. G. M. F.
Published: January 2005

The ultrastructure of contacts between axonal growth cones and glial cells in the developing pyramidal tract was examined by serial sectioning at the third cervical spinal cord segment in 0‐, 2‐, and 4‐day‐old rats. Junctional specializations, composed of synapse‐like contacts and invaginations, were frequently observed at the contact zone between growth cones and glial elements. The synapse‐like contacts consist of clear, round vesicles of 43 ± 6 nm in the presynaptic growth cone, a pre‐ and a postsynaptic density, separated by a cleft of 12.1 ± 0.9 nm. The invaginations consist of small protrusions of the growth cone into the glial element. The invaginated glial membrane is coated. Within the glial element, close to the invagination, frequently organelles were observed that closely resemble endosomes and prelysosomes. Therefore, it is suggested that the invagination represents a stage in endocytosis or possibly phagocytosis of the protruding part of the growth cone by the glial cell. The junctional specializations are formed by growth cones and, less frequently, by axon shafts. The targets of these specialized contacts are, in general, immature glial cells located within the tract area. Occasionally, however, invaginations were also observed into myelinating oligodendrocytes, suggesting that the population of immature target cells includes oligodendrocyte precursors.

With regard to the functional significance of these temporary growth cone‐glial contacts, several possibilities are discussed, including the suggestion that outgrowing pyramidal tract axons provide immature glial cells with chemical messages, which may influence the timing of glial cell maturation in the tract.
Acetylcholinesterase‐rich neurons of the human cerebral cortex: Cytoarchitectonic and ontogenetic patterns of distribution
Authors: Mesulam M‐Marsel , Geula Changiz
Published: January 2005

Layers 3 and 5 of the adult human cerebral cortex contain a very large number of pyramidal neurons that express intense acetylcholinesterase (AChE) enzymatic activity and AChE‐like immunoreactivity. The density of these neurons is high in motor, premotor, and neocortical association areas but quite low in paralimbic cortex. Those AChE‐rich neurons are located predominantly within layer 3 in the premotor and association cortex, within layer 5 in the non‐isocortical components of the paralimbic cortex, and are equally prominent in layers 3 and 5 in the motor cortex. Almost all Betz cells in the motor cortex and up to 80% of layer 3 pyramidal neurons in some parts of the association neocortex yield an AChE‐rich staining pattern. The existence of a specific laminar and cytoarchitectonic distribution suggests that the AChE‐rich enzymatic pattern of these neurons is selectively regulated.

The AChE‐rich enzymatic reactivity of the layer 3 and layer 5 neurons is not detectable during early childhood, becomes fully established during adulthood, and does not show signs of decline during advanced senescence in mentally intact individuals. The AChE activity (or enzyme synthesis) in these neurons is therefore held in check for several years during infancy and childhood and begins to be expressed at a time when the more advanced motor and cognitive skills are also being acquired.

The absence of immunostaining with an antibody to choline acetyltransferase suggests that these AChE‐rich neurons are not cholinergic. The regional distribution of these AChE‐rich neurons does not parallel the regional variations of cortical cholinergic innervation. Whereas the AChE‐rich pyramidal neurons of layers 3 and 5 almost certainly represent one subgroup of cholinoceptive cortical neurons, their AChE‐rich enzymatic pattern is probably also related to a host of non‐cholinergic processes that may include maturational changes and plasticity in the adult brain.
Position of axons in the cat's optic tract in relation to their retinal origin and chiasmatic pathway
Authors: Reese B. E. , Guillery R. W. , Marzi C. A. , Tassinari G.
Published: January 2005

The positions of the crossed and uncrossed optic axons of distinct diameter classes has been examined in the optic tract of the adult cat. In addition, the retinal origin of axons occupying different positions within the tract has been studied. Since the position of a fibre within the optic tract reflects its time of arrival during development, we have used axonal position as an indicator of age and have related this to the chiasmatic pathway choice of the axons.

Cats were either monocularly enucleated, to reveal the position and diameter of surviving crossed and uncrossed optic axons in semithin and thin sections, or implants of horseradish peroxidase (HRP) were placed so as to retrogradely label the ganglion cells giving rise to axons within the deep (early arriving), or superficial (later arriving) parts of the tract selectively. This was accomplished by either (1) surgically implanting HRP into the superficial portion of the optic tract, via a transbuccal approach, or (2) making such a transbuccal transection of the superficial fibres, followed by intracerebral injections of HRP to retrogradely label the surviving, deeper, optic axons from their target nuclei.

The deep parts of the optic tract contain fine and medium, crossed and uncrossed axons arising from mainly medium sized cells in the contralateral nasal and the ipsilateral temporal retina; there is a clear line of decussation. In contrast, the superficial parts of the tract contain mainly fine diameter axons arising from small cells in the whole contralateral retina, and a small proportion of large diameter axons arising from large, alpha cells in the whole contralateral retina and in the ipsilateral temporal retina.

The likelihood that axons from the temporal retina will project contralaterally therefore increases as development proceeds, since these axons are found in the superficial parts of the tract only. This suggests that a time‐dependent signal that weakens with age is responsible for directing early arriving optic axons from the temporal retina to take an exclusively uncrossed course.
Enkephalin immunoreactivity and messenger RNA in a discrete projection from the nucleus of the solitary tract to the nucleus ambiguus in the rat
Authors: Cunningham E. T. , Simmons D. M. , Swanson L. W. , Sawchenko P. E.
Published: January 2005

Previous work described in the rat a circumscribed, partly somatostatinergic, interneuronal projection from the esophageal afferent part of the nucleus of the solitary tract (NTSc) to esophageal motor neurons in the compact formation of the nucleus ambiguus(NAcf; Cunningham and Sawchenko, J Neurosci 9:1668, 1989). In the present study, axonal transport, immunohistochemical and in situ hybridization histochemical techniques were used to determine whether enkephalin (ENK), a peptide known to be expressed in a number of somatostatin‐containing medullary cell groups, is also expressed in the projection from the NTSc to the NAcf. The results may be summarized as follows; 1) cells immunoreactive (IR) for prepro‐enkephalin (ppENK)‐derived peptides were found in the NTSc in colchicine‐pretreated animals; in untreated animals, a dense ENK‐IR terminal field was observed in the NAcf; sections stained with antisera against dynorphin‐related peptides showed sparse staining in both regions; 2) signal indicating the presence of ppENK messenger RNA (mRNA) was found over the NTSc, including over a majority of cells identified using a retrograde tracing technique as projecting to the region of the NAcf; the signal for ppENK mRNA signal was greater than that for prepro‐somatostatin (ppSS) in the NTSc; 3) a combined anterograde tracing‐immunohistochemical technique demonstrated a strong correspondence between the distribution of inputs from the NTS to the NAcf, and the distribution of endogenous ENK‐IR varicosities; in addition, leucine (L)‐ENK‐IR was found in an appreciable number of varicosities in the NAcf that had been anterogradely labeled from the NTSc; 4) unilateral electrolytic lesions of the rostromedial NTS, which included the central subnucleus, virtually eliminated ENK‐IR in the ipsilateral NAcf, while staining on the contralateral side was unaffected. Taken together, these studies provide evidence that ppENK‐ and ppSS‐derived peptides are expressed in the pathway from the NTSc to the NAcf, a pathway thought to play a role in the reflex control of esophageal peristalsis.
Formation of ganglia in the gut of the chick embryo
Authors: Epstein Miles L. , Poulsen Kristian T. , Thiboldeaux Robert
Published: January 2005

We have examined the formation of myenteric ganglia in the developing avian enteric nervous system. The monoclonal antibody HNK‐1 was used to identify neural‐crest‐derived cells in whole mounts of fore‐ and midgut of chick embryos. We find that the crest‐derived cells extend processes to their neighbors and form a complex network in the wall of the gut. Formation of this network is an unusual behavior of crest‐derived cells and suggests the gut microenvironment is critical to this behavior. This cellular network disappears after ablation of the vagal neural crest, indicating the HNK‐1‐stained cellular network arises from crest‐derived cells. The network is found in the gut wall before the vagal nerve fibers are present. This network is first found in the primordium of the proventriculus, distal to the evagination of the lung buds, and progresses just proximal to the yolk stalk at embryonic day (E)3.5 and almost to the ileocecal junction at E5.5. The number of cells and the complexity of the network decrease in a rostral‐caudal direction down the length of the gut at these stages. The leading edge of the network consists of cells serially arranged in longitudinally running strands. The organization of the network changes with increasing embryonic age; we have focused on network changes in the proventriculus. In the primordium of the proventriculus at E3.5, the network consists of a cluster of one or two adjacent crest‐derived cells, which extend processes to a number of neighboring crest‐derived cells. At E5.5 large increases in the number of cells per cluster and in the length of cellular connectives between clusters are apparent. At E6.5 a crude meshwork of clusters is seen. At E10.5 the arrangement of cell clusters resembles the pattern of ganglia found in the adult myenteric plexus. This network may provide the environmental cues for the differentiation of enteric neurons and a framework for the pattern of ganglia found in the adult enteric nervous system.
Dopamine‐immunoreactive neurones in the central nervous system of the pond snail Lymnaea stagnalis
Authors: Elekes K. , Kemenes G. , Hiripi L. , Geffard M. , Benjamin P. R.
Published: January 2005

The distribution of dopamine and dopamine‐immunoreactive neurones was studied in the central nervous system of the snail Lymnaea stagnalis. The results from immunocytochemical labelling were compared with those from the application of the glyoxylic acid fluorescence method and 6‐hydroxydopamine‐induced pigment labelling. Comparisons were also made between the number of dopamine immunoreactive neurones and the dopamine content of the ganglia, measured by high‐performance liquid chromatography.

Dopamine immunocytochemistry proved to be superior to the other two histochemical techniques in terms of specificity and sensitivity. The 6‐hydroxydopamine‐induced pigment labelling failed to prove a useful tool for the in vivo identification of all dopamine‐containing neurones. The distribution and number of dopamine‐immunoreactive neurones and levels of biochemically measured dopamine in specific ganglia showed a close correspondence. By using the results of the dopamine immunocytochemistry and glyoxylic acid technique, a detailed map of dopamine‐containing neurones was constructed. Dopamine‐containing inter‐ and intra‐ganglionic axon tracts were also demonstrated. The mapping of dopamine‐containing neurones will facilitate further neurophysiological analysis of dopaminergic neural mechanisms in Lymnaea.
Trigeminal projections to the nucleus submedius of the thalamus in the rat
Authors: Yoshida Atsushi , Dostrovsky Jonathan O. , Sessle Barry J. , Chiang Chen Yu
Published: January 2005

Methods involving the anterograde and retrograde transport of wheat‐germ agglutinin conjugated horseradish peroxidase and the retrograde transport of Fluoro‐Gold were used in rats to examine the distribution within the spinal trigeminal nucleus of trigeminal neurons projecting to the nucleus submedius (Sm) of the thalamus, as well as the distribution of axon terminals within the Sm. Following injections into the trigeminal nucleus, axon terminals were seen in the dorsal part of the anterior Sm; the terminals occurred bilaterally but had an obvious contralateral dominance. To help determine the precise location of the Sm‐petal neurons, the border between trigeminal subnuclei interpolaris and caudalis was examined by the use of immunohistochemical procedures for calcitonin gene‐related peptide (CGRP). The Sm‐petal neurons that were labeled retrogradely occurred only at the caudal interpolaris and rostral caudalis levels; the number of labeled neurons on the contralateral side was approximately six times that on the ipsilateral side. Most of these neurons were located in the ventral part of the caudal interpolaris and rostral caudalis and spinal trigeminal tract; in caudalis, the neurons were almost exclusively localized to its superficial layers. There were approximately three times more labeled neurons in interpolaris than in caudalis. In the experiments combined with immunohistochemistry for CGRP, many neurons (34%) were seen in proximity to CGRP‐like immunopositive fibers. These results suggest that the Sm of the rat receives its orofacial afferent inputs from brainstem neurons that are localized to the caudal interpolaris and rostral caudalis. In view of previous studies that have implicated these three structures in somatosensory function, and in particular nociception, our data point to a role for this direct projection from interpolaris and caudalis to Sm in the central processing of pain.
Intracerebral grafting of cultured autologous skin fibroblasts into the rat striatum: An assessment of graft size and ultrastructure
Authors: Kawaja Michael D. , Fagan Anne M. , Firestein Bonnie L. , Gage Fred H.
Published: January 2005

To identify a suitable donor cell population for gene therapy applications to the central nervous system, primary fibroblasts isolated from skin biopsies and maintained in culture are employed as autologous cells for intracerebral grafting within the adult rat striatum. Results from the present investigation reveal that cultured primary skin fibroblasts cease to proliferate once they reach confluence; these cells are thus contact inhibited in vitro. Following implantation within the striatum, the volume of the primary fibroblast grafts, stained immunohistochemically for fibronectin, does not differ significantly at 3 and 8 weeks. The graft size is dependent on the density of the cell suspension, but not dependent on either the number of passages the cells are taken through in culture prior to grafting or on the postoperative survival period. Ultrastructural evidence reveals that at 8 weeks the grafts are composed primarily of collagen and fibroblasts with rough endoplasmic reticulum and vesicles. Reactive astrocytic processes and phagocytic cells are also present in the grafts, The grafts are extensively vascularized with capillaries composed of nonfenestrated endothelium; intercellular junctions are evident at sites of apposition between endothelial cells. It is concluded that primary skin fibroblasts are able to survive for at least 8 weeks following intracerebral implantation and continue to synthesize collagen and fibronectin in vivo. Also, the grafts maintain a constant volume between 3 and 8 weeks, thereby indicating that primary skin fibroblasts do not produce tumors. Finally, dynamic host‐to‐graft interactions‐including phagocytic migration, astrocytic hypertrophy and infiltration within the grafts, and angiogene‐sis‐are features that constitute the structural integration of primary skin fibroblasts grafted within the adult rat central nervous system.
Localization of serotonin, tyrosine hydroxylase, and leu‐enkephalin immunoreactive cells in the brainstem of the horn shark, Heterodontus francisci
Authors: Stuesse Sherry L. , Cruce William L. R. , Northcutt R. Glenn
Published: January 2005

In previous studies on reptiles and elasmobranchs, we determined that some reticular groups are either absent or may be displaced compared to their locations in mammals. For example, nucleus raphe dorsalis, the largest serotoninergic cell group in mammals, is not present in rays, skates, or guitarfish. In the present study, we chose heterodontid sharks, a sister group to these batoids, for an out‐group comparison of this and other characters. We identified cells in the brainstem of Heterodontus francisci by use of antibodies against tyrosine hydroxylase, serotonin, or leu‐enkephalin and compared the distribution of these nuclei to descriptions in mammals and other elasmobranchs. The majority of tyrosine hydroxylase‐positive cells were found in the midbrain tegmentum (A8–A10) and the hypothalamus. In addition, putative A1, A2, A5, A7 (noradrenergic) groups were found in the metencephalon and myelencephalon. Serotonin‐positive cells were found in raphe nuclei and scattered lateral to the raphe. We identified probable homologues to raphe pallidus, raphe obscurus, raphe magnus, and raphe centralis superior (B8) cell groups, which have been described in mammals. A cluster of cells dorsomedial to the medial longitudinal fasciculus was identified as raphe dorsalis. The distributions of leu‐enkephalin and serotonin immunoreactive cells were similar to each other, but the tyrosine‐hydroxylase immunoreactive cells rarely intermingle with the former two immunoreactive cell types. Other reticular groups that contained both serotonin‐and leu‐enkephalin‐positive cells included reticularis (r.) ventralis, r. magnocellularis, r. paragigantocellularis lateralis, r. pontis caudalis, and r. pontis oralis medialis and lateralis. Thus, this shark contains many of the major brainstem raphe and catecholaminergic cell groups described for rats, but the relative distribution of the immunopositive cell groups differs in mammals and cartilaginous fish.
Mapping of glial fibrillary acidic protein‐immunoreactivity in the rat forebrain and mesencephalon by computerized image analysis
Authors: Zilles Karl , Hajós Ferenc , Kálmán Mihály , Schleicher Axel
Published: January 2005

Computer‐assisted image analysis was used to map the regional distribution of glial fibrillary acidic protein‐immunoreactive (GFAP‐IR) astrocytes in the rat forebrain, and mesencephalon. A complete survey of packing densities of GFAP‐IR structures was performed. Computer maps revealed high values in the outer and inner layers of the cortex, some hippocampal and olfactory bulb layers, prepiriform cortex, dorsal part of the caudate‐putamen, globus pallidus, lateral septum, reticular thalamic nucleus, lateral habenular nucleus, circumventricular organs, nuclei of the medial hypothalamus, substantia nigra, interpeduncular nucleus, and mamillary body. These correspond to regions of the embryonic pial and ventricular brain surfaces, which undergo developmental alterations including growth and various forms of internalization. From this we conclude that in the adult brain, astrocytes of high GFAP‐IR are derivatives of surface‐contact glia, whereas those located in areas having developed by the local thickening of the neural tube wall show reduced or no GFAP‐IR.
Calcium‐binding protein (calbindin‐D28K) and parvalbumin immunocytochemistry in the normal and epileptic human hippocampus
Authors: Sloviter Robert S. , Sollas Anne L. , Barbaro Nicholas M. , Laxer Kenneth D.
Published: January 2005

The calcium‐binding proteins calbindin‐D28K (CaBP) and parvalbumin (PV) were localized in the “normal” and “epileptic” human hippocampus to address the possible relationship between the expression of these constitutive cytosolic calcium‐binding proteins and the resistance or selective vulnerability of different hippocampal neuron populations in temporal lobe epilepsy. Compared to rodents and a baboon (Papio papio), the pattern of CaBP‐like immunoreactivity (LI) in the “normal” human hippocampus is unique. CaBP‐LI is present in the dentate granule cells, neurons of the “resistant zone” (area CA2), and presumed interneurons of all regions. Unlike rodent and baboon CA1 pyramidal cells, human CA1 pyramidal cells appear to be devoid of CaBP‐LI. Thus, the relatively resistant dentate granule cells and CA2 pyramidal cells are the only human hippocampal principal cells that contain CaBP‐LI normally. As in lower mammals, PV‐LI is present exclusively in interneurons of all human hippocampal subregions.

CaBP‐ and PV‐LI were localized in hippocampi surgically removed in the treatment of intractable temporal lobe epilepsy to determine whether surviving hippocampal cells were those that express these calcium‐binding proteins. Hippocampi removed from patients with tumors or arteriovenous malformations that were associated with complex partial seizures arising from this region appeared relatively normal histologically. CaBP‐ and PV‐LI in this patient group appeared similar to that seen in autopsy controls. Conversely, “cryptogenic” epileptics, who exhibit hippocampal sclerosis as the only lesion associated with the epilepsy, exhibited a preferential survival of hippocampal cells that were CaBP‐ or PV‐immunoreactive. In the dentate hilus, which normally contains few CaBP‐LI neurons, most of the few surviving hilar neurons were CaBP‐immunoreactive. Their number and darkness of staining suggests that CaBP synthesis may be increased in cells that survive. Despite an obvious decrease of PV‐LI specifically in the damaged parts of the sclerotic hippocampi, PV‐immunoreactive interneurons were often among the few surviving cells. Nevertheless, large expanses of the surviving granule cell layer appeared to have lost the PV‐immunoreactive axosomatic fiber plexus.

These results reveal a unique and striking correlation between the human hippocampal cells that normally express these calcium‐binding proteins and those that survive in the sclerotic epileptic hippocampus.
Use of a digital brain atlas to compare the distribution of NGF‐ and bFGF‐protected cholinergic neurons
Authors: Schwaber James S. , Due Bryan E. , Rogers Wade T. , Junard Emmanuel O. , Sharma Anita , Hefti Franz
Published: January 2005

The effectiveness of basic fibroblast growth factor and nerve growth factor in preventing the lesion‐induced disappearance of septal cholinergic neurons was compared by using a computerized data‐acquisition system and a digital brain atlas that yielded quantitative and distributional information. Adult rats were given unilateral partial transections of the fimbria and then received daily intraventricular injection of one of the growth factors for 15 days. Given the high degree of co‐localization of nerve growth factor receptors with choline acetyltransferase in these areas, cholinergic neurons were identified by nerve growth factor receptor immunoreactivity. Their locations were plotted in the context of a three‐dimensional brain atlas permitting the analysis of relative distributions of cholinergic neurons in control brains and those of animals treated with each growth factor. The cholinergic cell disappearance induced by the partial fimbrial transection was restricted to the medial septal nucleus and the vertical limb of the diagonal band of Broca. Within the affected areas cholinergic cell disappearance increased gradually in severity from anterior to posterior levels of the septal nucleus. Both growth factors prevented the disappearance of cholinergic cell bodies in medial septal nucleus and vertical limb of the diagonal band. In lesioned control animals the unilateral cell disappearance amounted to 53.5% of the number of cholinergic neurons of the unlesioned side. Nerve growth factor and basic fibroblast growth factor reduced this disappearance to 13% and 28%, respectively. The distribution of cholinergic cells was the same in animals treated with each growth factor, suggesting that the two growth factors protect the same population of cholinergic neurons.
The regeneration of electroreceptors in kryptopterus
Authors: Bever Michele Miller , Borgens Richard B.
Published: January 2005

The regeneration of ampullary electroreceptors was studied in the living catfish, Kryptopterus, by differential interference contrast optics. Electroreceptors in this transparent catfish are found, among other places, along the proximal portion of each anal fin ray, while the distal portion does not contain electroreceptors. Upon interruption of the sensory innervation, the electroreceptors disappear but regenerate when the skin is reinnervated. In this study, we tested the role of the skin and nerve in receptor regeneration with the following two experiments. First, a plug of fin containing electroreceptors was removed to determine whether electroreceptors could form in regenerated skin after the complete removal of all of the receptors within an interradial zone of the anal fin. Second, a portion of anal fin that contained electroreceptors was excised and a graft of electro receptor‐free (EF) fin was sutured in its place to determine whether epidermis that does not normally contain these receptors can be induced to form them. These grafts were compared to control grafts taken from proximal electroreceptor‐containing (EC) fin. By 2 weeks following surgery, receptors were found in regenerated fin tissue and within the EC grafts. Electroreceptors also formed within most of the EF grafts. As electroreceptor regeneration does not require the presence of degenerated organs, and as electroreceptors can form in fin that normally does hot contain receptors, we suggest that the formation of electroreceptors does not require old target sites and that epidermal cells can be induced to form receptors upon contact by regenerating axons. We discuss as well the factors that influence the pattern of receptor reappearance.
Distribution of galanin‐like immunoreactivity in the brain of Rana esculenta and Xenopus laevis
Authors: Lázár Gyula Y. , Liposits Zsolt S. , Tóth Pál , Trasti Scott L. , Maderdrut Jerome L. , Merchenthaler István
Published: January 2005

The immunocytochemical distribution of galanin‐containing perikarya and nerve terminals in the brain of Rana esculenta and Xenopus laevis was determined with antisera directed toward either porcine or rat galanin. The pattern of galanin‐like immunoreactivity appeared to be identical with antisera directed toward either target antige.

The distribution of galanin‐like immunoreactivity was similar in Rana esculenta and Xenopus laevis except for the absence of a distinct laminar distribution of immunoreactivity in the optic tectum of Xenopus laevis. Galanin‐containing perikarya were located in all major subdivisions of the brain except the metencephalon. In the telencephalon, immunoreactive perikarya were detected in the pars medialis of the amygdala and the preoptic area. In the diencephalon, immunoreactive perikarya were detected in the caudal half of the suprachiasmatic nucleus, the nucleus of the periventricular organ, the ventral hypothalamus, and the median eminence. In the mesencephalon, immunoreactive perikarya were detected near the midline of the rostroventral tegmentum, in the torus semicircularis and, occasionally, in lamina A and layer 6 of the optic tectum. In the myelencephalon, labelled perikarya were detected only in the caudal half of the nucleus of the solitary tract. Immunoreactive nerve fibers of varying density were observed in all subdivisions of the brain with the densest accumulations of fibers occurring in the pars lateralis of the amygdala and the preoptic area. Dense accumulations of nerve fibers were also found in the lateral septum, the medial forebrain bundle, the periventricular region of the diencephalon, the ventral hypothalamus, the median eminence, the mesencephalic central gray, the laminar nucleus of the torus semicircularis, several laminae of the optic tectum, the interpeduncular nucleus, the isthmic nucleus, the central gray of the rhombencephalon, and the dorsolateral caudal medull.

The extensive system of galanin‐containing perikarya and nerve fibers in the brain of representatives of two families of anurans showed many similarities to the distribution of galanin‐containing perikarya and nerve fibers previously described for the mammalian brai.
Postnatal ontogeny of cells expressing prepro‐neurotensin/neuromedin N mRNA in the rat forebrain and midbrain: A hybridization histochemical study involving isotope‐labeled and enzyme‐labeled probes
Authors: Sato Makoto , Kiyama Hiroshi , Yoshida Shigetaka , Saika Takanori , Tohyama Masaya
Published: January 2005

The postnatal ontogeny of cells expressing prepro‐neurotensin/neuromedin N messenger RNA (prepro‐NT/NN mRNA) in the rat forebrain and midbrain was investigated by in situ hybridization histochemistry. According to the pattern of expression during development, the cells which express prepro‐NT/NN mRNA can be roughly divided into 2 groups. In type I cells, prepro‐NT/NN mRNA expression reaches a maximum in terms of content during the postnatal period. After this early peak, cells of this type express the same or less prepro‐NT/NN mRNA, reaching a plateau at an adult level that still contains a high level of expression. In type II cells, prepro‐NT/NN mRNA appears during the postnatal period, and the expression decreases dramatically after the first postnatal week, being almost undetectable by a few weeks after birth. Type I cells were observed in the following areas: the piriform cortex, field CA1 of Ammon's horn, subiculum, vertical, and horizontal limbs of the diagonal band of Broca, intermediate part of the lateral septal nucleus, bed nucleus of the stria terminalis, medial preoptic area, lateral hypothalamus, caudal part of the caudate putamen, medial, cortical, and central amygdaloid nuclei, ventral tegmental area, deep mesencephalic nucleus, cuneiform nucleus, dorsal raphe nucleus, laterodorsal tegmental nucleus, parabrachial nucleus, and oral part of the pontine reticular nucleus. Cells of type II were observed in the following areas: the mitral cell layer of the olfactory bulb, rostral part of the caudate putamen, (anterior) cingulate cortex, and retrosplenial cortex (posterior cingulate cortex).