bluuebunny/crossref_metadata_2025_split huggingface dataset:
A serial section electron microscope study of an identified la afferent collateral in the cat spinal cord
Authors: Nicol Madeleine J. , Walmsley Bruce 
Published: January 2005

AbstractSerial section electron microscopy has been used to examine a horseradish peroxidase (HRP)‐labelled group Ia afferent collateral from its entry point in the grey matter to its termination in Clarke's column of the cat spinal cord. A wide range of geometries and myelination patterns were identified along the collateral, including (1) nodes specialized to exhibit a single synaptic bouton, (2) nodes specialized to exhibit two or more synaptic boutons connected by fine, unmyelinated lengths of the collateral, (3) terminal heminodes, along which boutons were separated by unmyelinated branches, and (4) complex arrangements along which myelinated and unmyelinated branches gave rise to one or more boutons. Thirty‐six synaptic boutons of varied shape and size were exhibited by this collateral.Previous studies have shown that the geometry, branching, and myelination pattern of an axon play an important role in determining the amplitude and duration of an action potential propagating along that axon. In turn, the amplitude and duration of a presynaptic action potential influence the efficacy of transmitter release. The varied axonal geometries and myelination patterns observed in the present study provide further evidence in support of our previous proposal that there may be considerable nonuniformity in the efficacy of synaptic transmission among release sites arising from the same primary afferent fiber.
Afferent and sympathetic neurons projecting into lumbar visceral nerves of the male rat
Authors: Baron Ralf , Jänig Wilfrid 
Published: January 2005

AbstractThe cell bodies of thoracolumbar sensory and sympathetic pre‐ and postganglionic neurons that project to the colon and pelvic organs of the male rat were labeled retrogradely with horseradish peroxidase (HRP) in order to study numbers, segmental distribution, and location of the somata of these neurons quantitatively. HRP was applied to one hypogastric nerve (HGN), to the lumbar colonic nerves (LCN) and to the intermesenteric nerve (IMN). In order to estimate the significance of the branching of one axon into both hypogastric nerves a double‐labeling technique with fluorogold and HRP was used.About 2640 neurons project into the two HGN added together (800 afferent, 1320 pre‐, and 520 postganglionic), 4650 neurons into the LCN (360 afferent, 0 pre‐ and 4290 postganglionic), and 5990 into the IMN (1500 afferent, 1250 pre‐, and 3240 postganglionic). About 4190 sympathetic postganglionic prevertebral neurons innervate the colon and pelvic organs, 1900 are located in the inferior mesenteric ganglion and 2290 in ganglia of the IMN. Considering the efferent component, the HGN mainly are preganglionic and the LCN exclusively postganglionic nerves. Branching of one axon into both HGN is a rare event and quantitatively negligible (< 3%).Afferent neurons of all three nerves were found in the dorsal root ganglia (DRG) T12‐L2 with the maximum in L1 and L2. The distribution of afferent neurons projecting into the LCN is shifted slightly more rostrally compared to neurons projecting into the HGN. The IMN distribution is located in a position in between. Preganglionic neurons projecting into the IMN are located in the spinal cord segments T12‐L3 with the maximum in LI and L2. Sympathetic postganglionic paravertebral neurons of all three types of nerves are more widely distributed (T12‐L5). Neurons projecting into the LCN are shifted more caudally than those projecting into the HGN.
Time of origin of neurons in the murine enteric nervous system: Sequence in relation to phenotype
Authors: Pham Tuan D. , Gershon Michael D. , Rothman Taube P. 
Published: January 2005

AbstractThe hypothesis was tested that developing enteric neurons withdraw from the cell cycle in a sequence related to their phenotype. The birthdays of immunocytochemically identified myenteric and submucosal neurons were determined in the murine duodenum and jejunum. [3H]thymidine ([3H]TdR) was injected into timed pregnant mice or pups at 4–8 hour intervals over a 24 hour period. Pups were killed on postnatal day 30 (P30). [3H]TdR incorporation was detected by radioautography in enteric neurons, which were phenotypically identified by the simultaneous detection of the immunoreactivities of 5‐hydroxytryptamine (5‐HT), choline acetyl transferase (ChAT), neuropeptide Y (NPY), enkephalin (ENK), calcitonin gene‐related peptide (CGRP), and vasoactive intestinal peptide (VIP). The dates of the earliest withdrawal from the cell cycle of neurons containing these markers were determined, as well as the length of time during which the identified neurons continued to be born, and the date on which their rate of birth was maximal. The birthdates of myenteric neurons that contained 5‐HT (E8–E14, peak at E10) or ChAT (E8–E15, peak at E12) tended to be earlier than those that contained ENK (E10–E18, peak at E14), NPY (E10–E18, peak at E15), VIP (E10–P5, peak at E15), or CGRP (E10–P3, peak at E17). For any given immunocytochemically defined neuronal phenotype, submucosal neurons tended to be born later than their myenteric counterparts and submucosal neurons that contained neuropeptides were born later than those that contained only ChAT immunoreactivity. The day (E8) on which the first 5‐HT‐ and ChAT‐immunoreactive neurons became postmitotic is earlier than the day (E9) on which the colonization of the bowel by crest‐derived cells has been detected. The population of neural precursors that colonizes the gut, therefore, is heterogeneous; many cells are proliferating, but a specific subset, which will ultimately give rise to serotoninergic or cholinergic neurons, is already postmitotic. Neurons continued to be born throughout fetal life and even after birth. Consequently, terminally differentiated neurons coexist in the developing enteric nervous system with dividing neural precursor cells. This observation is consistent with the idea that early developing neurons could affect the development of enteric neural precursors; moreover, they also demonstrate that it is possible to add neurons to the enteric plexuses even after the neural circuits on which the bowel depends have become functional.
Octopamine immunoreactive cell populations in the locust thoracic‐abdominal nervous system
Authors: Stevenson P. A. , Pflüger H.‐J. , Eckert M. , Rapus J. 
Published: January 2005

AbstractWe describe octopamine‐immunoreactive somata and their projections in the pro‐ meso‐, meta‐ and pregenital abdominal‐ganglia of locusts. Immunoreactive midline somata were identified as dorsal‐ and ventral‐ unpaired median (DUM‐ and VUM‐, respectively) neurones due to their: characteristic large size and positions of somata, primary neurites in DUM‐tracts giving rise to T‐junctions, and bilaterally projecting axons. In the prothoracic ganglion there are most likely 8 such cells; in the meso‐ and metathoracic, some 20 each; and in each individual pregenital abdominal ganglion, typically 3. All appear to project to peripheral nerves and their numbers correspond to the number of peripherally projecting DUM‐cells identified to date in each ganglion. We suggest that probably all peripherally projecting DUM‐cells are octopaminergic in the examined ganglia. Presumptive DUM‐interneurones are not octopamine‐immunoreactive, but, confirming other studies, are shown to label with an antiserum to γ‐amino butyric acid (GABA).Other octopamine‐immunoreactive neurones include a pair of midline, prothoracic, anterior medial cells, not necessarily DUM‐cells, and a pair of ventral lateral somata in each thoracic‐ and the first abdominal ganglion. The latter project intersegmentally in ventral tracts. Intersegmentally projecting octopamine‐immunoreactive fibers in dorsal tracts probably arise from a prothoracic DUM‐cell, which leaves through suboesophageal nerves, or descending suboesophageal DUM‐cells. Thus, the octopamine‐immunoreactive system of thoracic and pregenital abdominal ganglia in locust comprises all peripherally projecting DUM‐cells and a plurisegmental network.
Nitric oxide synthetase (NOS)‐containing sympathoadrenal cholinergic neurons of the rat IML‐cell column: Evidence from histochemistry, immunohistochemistry, and retrograde labeling
Authors: Blottner Dieter , Baumgarten Hans‐Georg 
Published: January 2005

AbstractNitric oxide synthetase (NOS) can be selectively stained in neurons by either NADPH‐diaphorase (i.e., NOS)‐histochemistry or immunohistochemistry with antibodies raised against NOS, which apparently label identical reactive sites (Hope, B.T., G.J. Michael, K.M. Knigge, and S.R. Vincent, Proc. Natl. Acad. Sci. USA 88:2811–2814, '91). We provide histochemical evidence for the existence of a neuron‐specific NOS‐activity in autonomic neurons of the thoracic spinal cord. Among the four main preganglionic cell clusters investigated at mid‐thoracic levels, Th7–10, the intermediolateral (IML)‐cell column was the most prominently stained cell group. The histochemical staining was absent in other spinal cord neurons and non‐neuronal cells, e.g., GFAP‐positive glial cells. Staining was completely blocked by Nω‐nitro‐L‐arginine (L‐NNA), a potent NOS‐inhibitor for brain and peripheral autonomic neurons, but was still observed in the presence of another NOS‐inhibitor, Nω‐monomethyl‐L‐arginine (MeArg). The NOS‐activity co‐localized with nearly half of the ChAT‐immunostained neurons located in the mid‐thoracic IML‐cell column as quantified by cell counts in single and double‐stained tissue sections. We conclude that NOS‐activity‐containing neurons represent a distinct group among cholinergic IML‐neurons, which suggests a more general function of this newly defined subpopulation of the spinal cord autonomic system. In vivo Fast blue retrograde labeling combined with histochemical staining and immunostaining revealed that sympathoad‐renal projection neurons belong to the distinct NOS and ChAT‐positive IML‐cell group. The results are consistent with the idea of a crucial role of NOS and the related L‐arginine‐dependent nitric oxide biosynthesis for adrenomedullary innervation and autonomic control of adrenal gland function.
Claustrum in the hedgehog (Erinaceus europaeus) brain: Cytoarchitecture and connections with cortical and subcortical structures
Authors: Dinopoulos A. , Papadopoulos G. C. , Michaloudi H. , Parnavelas J. G. , Uylings H. B. M. , Karamanlidis A. N. 
Published: January 2005

AbstractThe Cytoarchitecture of the claustrum in the hedgehog (Erinaceus europaeus) brain, the morphology of its neurons, and the efferent connections with cortical and subcortical structures were studied with the Nissl and Klüver‐Barrera, the Golgi, and the horseradish peroxidase methods. It was found that the claustrum is a well developed nucleus in the hedgehog telencephalon and, as in other mammals, is divided into dorsal and ventral parts. In Golgi‐stained sections, spiny multipolar cells are the predominant neurons of both the dorsal and the ventral claustrum and are projection neurons. Aspiny multipolar neurons with fewer, often beaded, dendrites constitute a minority in both divisions and are interneurons.Injections of wheat germ agglutinin‐horseradish peroxidase (WGA‐HRP) in the prefrontal, motor, somatosensory, auditory and visual areas, and HRP or WGA‐HRP injections in the thalamus showed that: (1) the claustroneocortical projections originate in the dorsal claustrum and are distributed to the entire neocortex; these projections are mainly ipsilateral but some also originate contralaterally; (2) the claustroneocortical projections show a rough topographic organization; there exists a substantial degree of overlap; and (3) the claustrothalamic projection, arising throughout the dorsal claustrum, is strictly ipsilateral. No evidence of a thalamoclaustral projection was found.The present results suggest that, although the hedgehog has been referred to as a “paleocortical mammal” owing to the great development of its rhinencephalic structures in comparison with its small neocortex, the dorsal claustrum is well developed and is connected with all neocortical areas as well as with the thalamus, establishing it as a key structure in the hedgehog forebrain.
Topographical organization and relationship with ventral striatal compartments of prefrontal corticostriatal projections in the rat
Authors: Berendse Henk W. , Graaf Yvonne Galis‐De , Groenewegen Henk J. 
Published: January 2005

AbstractThe anterograde tracer Phaseolus vulgaris‐leucoagglutinin was used to examine the topographical organization of the projections to the striatum arising from the various cytoarchitectonic subdivisions of the prefrontal cortex in the rat. The relationship of the prefrontal cortical fibres with the compartmental organization of the ventral striatum was assessed by combining PHA‐L tracing and enkephalin‐immunohistochemistry.The prefrontal cortex projects bilaterally with an ipsilateral predominance to the striatum, sparing only the lateral part of the caudate‐putamen complex. Each of the cytoarchitectonic subfields of the prefrontal cortex has a longitudinally oriented striatal terminal field that overlaps slightly with those of adjacent prefrontal areas. The projections of the medial subdivision of the prefrontal cortex distribute to rostral and medial parts of the striatum, whereas the lateral prefrontal subdivision projects to more caudal and lateral striatal areas. The terminal fields of the orbital prefrontal areas involve midventral and ventromedial parts of the caudate‐putamen complex. The projection of the ventral orbital area overlaps with that of the prelimbic area in the ventromedial part of the caudate‐putamen.In the “shell” region of the nucleus accumbens, fibres arising from the prelimbic area concentrate in areas of high cell density that are weakly enkephalin‐immunoreactive, whereas fibres from the infralimbic area avoid such areas. Rostrolaterally in the “core” region of the nucleus accumbens, fibres from deep layer V and layer VI of the dorsal part of the prelimbic area avoid the enkephalin‐positive areas surrounding the anterior commissure and distribute in an inhomogeneous way over the intervening moderately enkephalin‐immunoreactive compartment. The other prefrontal afferents show only a preference for, but are not restricted to, the latter compartment, In the border region between the nucleus accumbens and the ventromedial part of the caudate‐putamen complex, patches of strong enkephalin immunoreactivity receive prefrontal cortical input from deep layer V and layer VI, whereas fibres from more superficial cortical layers project to the surrounding matrix.Individual cytoarchitectonic subfields of the prefrontal cortex thus have circumscribed terminal domains in the striatum. In combination with data on the organization of the midline and intralaminar thalamostriatal and thalamoprefrontal projections, the present results establish that the projections of the prefrontal cortical subfields converge in the striatum with those of their midline and intralaminar afferent nuclei. The present findings further demonstrate that the relationship of the prefrontal corticostriatal fibres with the neurochemical compartments of the ventral striatum can be influenced by both the areal and the laminar origin of the cortical afferents, depending on the particular ventral striatal region under consideration.
Differential projections of the anterior and posterior regions of the medial amygdaloid nucleus in the syrian hamster
Authors: Gomez Diana M. , Newman Sarah Winans 
Published: January 2005

AbstractThe medial nucleus of the amygdala is important for the neural control of reproductive behavior in the adult male Syrian hamster. Two types of signals are essential for this behavior, chemosensory stimuli and gonadal steroids; these signals appear to be received in different parts of the medial nucleus. The anterior region receives input from olfactory and vomeronasal systems, both of which are required for this behavior, whereas the posterior region receives gonadal hormone inputs. Behavioral studies have also suggested a functional differentiation of these two areas; electrolytic lesions of the anterior, but not the posterior, part eliminates normal sexual behavior. In this study, the efferent projections of the anterior and posterior divisions of the medial nucleus of the amygdala in the Syrian hamster were analyzed throughout the forebrain after injections of the anterograde neuronal tracer, Phaseolus vulgaris‐leucoagglutinin. Neurons of the anterior, but not the posterior, medial nucleus, were found to project to numerous olfactory bulb projection areas and to the ventral striatopallidal complex. Within areas of the chemosensory circuitry that control reproductive behavior, the anterior region of the medial nucleus projects to the intermediate part of the posterior bed nucleus of the stria terminalis and the lateral part of the medial preoptic area, whereas the posterior region of the medial nucleus projects to the medial parts of these areas. Differences in targets were also observed in the ventromedial nucleus of the hypothalamus where the anterior region projects to the core while the posterior part projects to the shell of this nucleus. Furthermore, reciprocal projections between the anterior and posterior regions of the medial nucleus were observed. Taken together, these studies support the hypothesis that the anterior and posterior regions of the medial amygdaloid nucleus provide substantially different contributions to the control of reproductive behaviors.
Immunohistochemical localization of nicotinic acetylcholine receptor subunits in the mesencephalon and diencephalon of the chick (Gallus gallus)
Authors: Britto Luiz R. G. , Keyser Kent T. , Lindstrom Jon M. , Karten Harvey J. 
Published: January 2005

AbstractMonoclonal antibodies against two α‐bungarotoxin‐binding subunits (α7 and α8) of the nicotinic acetylcholine receptors (nAChRs) were used as immunohistochemical probes to map their distribution in the chick diencephalon and mesencephalon. The distribution of the α7 and α8 nAChR subunits was compared to the distribution of immunoreactivity produced by a monoclonal antibody against the β2 structural subunit of the nAChRs.Structures that contained high numbers of α7‐like immunoreactive (LI) somata included the intergeniculate leaflet, nucleus intercalatus thalami, nucleus ovoidalis, organum paraventricularis, nucleus rotundus, isthmic nuclei, nucleus trochlearis, oculomotor complex, nucleus interstitio‐pretecto‐subpretectalis, stratum griseum centrale of the optic tectum, and nucleus semilunaris. Neuropil staining for α7‐LI was intense in the nucleus dorsomedialis hypothalami, nucleus geniculatus lateralis ventralis, griseum tecti, isthmic nuclei, nucleus lentiformis mesencephali, nucleus of the basal optic root, and stratum griseum et fibrosum superficiale of the tectum. High numbers of α8‐LI somata were found in the stratum griseum et fibrosum superficiale of the tectum and the nucleus interstitio‐pretecto‐subpretectalis, and intense neuropil staining for α8‐LI was found in the dorsal thalamus, nucleus geniculatus lateralis ventralis, lateral hypothalamus, griseum tecti, nucleus lentiformis mesencephali, nucleus interpeduncularis, and stratum griseum et fibrosum superficiale of the tectum. High numbers of β2‐LI somata were found only in the nucleus spiriformis lateralis, whereas neuropil staining for β2‐LI was intense in the nucleus geniculatus lateralis ventralis, nucleus suprachiasmaticus, nucleus lateralis anterior, nucleus habenularis lateralis, area pretectalis, griseum tecti, nucleus lentiformis‐mesencephali, nucleus externus, and nucleus interpeduncularis, and in the stratum griseum centrale, stratum griseum et fibrosum superficiale, and stratum opticum of the tectum.These results indicate that there are major disparities in the localization of the α‐bungarotoxin‐binding α7 and α8 nAChR subunits and the β2 structural nAChR subunit in the chick diencephalon and mesencephalon. These nAChR subunits appear, however, to coexist in several regions of the chick brain.
Observations on the early development of the optic nerve and tract of the mouse
Authors: Colello R. J. , Guillery R. W. 
Published: January 2005

AbstractThe early development of the retinofugal pathway of mice has been studied by light and electron microscopic methods in order to define the spatial distribution and the structure of the growth cones as they advance from the eye to the brain. We have studied the relationships of the growth cones to each other, to the glia and, in the older individuals, to the nerve fibers that are already terminating in the brain. We have looked at the rate of advance of the growth cones and have paid particular attention to the changing relationships of the growth cones as they approach the optic chiasm. We have also looked to see whether, at early stages, it is possible to recognise any characteristic features distinguishing the fibers destined to be the thickest in the adult, which come from ganglion cells that are generated among the earliest ganglion cells.In transverse sections through the optic stalk about 50–100 μm behind the eye, the first bundles of fibers are seen on embryonic day 12.5 (E12.5) as a mixture of thin (< 0.5 μm) axons, thicker growth cones, and fine filopodial and foliopodial extensions. During the next two days, as these bundles in the intraorbital nerve increase in size and number, growth cones can be seen in all of the bundles and in all parts of the bundles. They show only a slight preference for one part of the nerve relative to another, and our material provides no evidence for the view that axons are particularly inclined to follow pre‐existing bundles.The structure of the pathway changes significantly as it is traced towards the chiasm, and no section or small stretch of sections can be regarded as representative of the nerve as a whole. As the fibers approach the optic chiasm the growth cones come to lie predominantly close to the pial surface, with the deeper regions occupied almost entirely by fine axons. The change occurs in a region where the glial environment also changes, and where a characteristic neural tube‐like organization first becomes recognizable. Here the glial cells lie in a periventricular position and send slender radial processes out towards the subpial surface.The newly invading axons in the early optic nerve taper from a broad growth cone back to an extremely slender axon, less than 0.5 μm in diameter. The tapered region is of the order of 100–300 μm in length and advances through the nerve at approximately 60 μm per hour. During days 13–19 about 20,000 fibers are added to the nerve each day and by the end of this period almost all of the growth cones have advanced beyond the nerve and tract. All of the axons now have a remarkably uniform, fine caliber, and in the tract there is no indication of the differences that later characterize axons in the different parts of the tract. The fibers destined to be the thickest as yet have no features that distinguish them from the others.