bluuebunny/crossref_metadata_2025_split huggingface dataset:
The visual system of the channel catfish (ictalurus punctatus). I. Retinal ganglion cell morphology
Authors: Dunn‐Meynell A. A. , Sharma S. C. 
Published: January 2005

AbstractHorseradish peroxidase was applied to lesions in the optic nerve of catfish (Ictalurus punctatus). The retinae were processed to reveal HRP‐labelled ganglion cells. The histochemical techniques employed allowed fine details of the dendritic arbor to be resolved. Flat‐mounted retinae were examined and the following characteristics were noted in individual ganglion cells: Soma area, shape, and depth; number and diameter of major dendrites; shape, area, and depth(s) within the inner plexiform layer (ipl) of the dendritic arbor; origin of the axon (from the soma or a dendrite). On the basis of these characteristics, eleven classes of ganglion cells were delineated: four classes of giant cells (Gl‐G4) and seven classes of smaller cells (Sl‐S7). G1 cells had dendrites arborizing in the most distal sublamina of the ipl. G1 cells in the dorsal retina had nasotemporally elongated dendritic arbors. G2 cells had dendrites in the proximal portion of the ipl. G3 cells were almost completely confined to a band running between the nasal and temporal retinal poles, through the center of the retina. In this location, the cells had dorsoventrally elongated dendritic arbors, which were bistratified in the ipl. G4 cells were displaced into the inner nuclear layer. S1 and S4 cells had axons arising from their somata, and dendrites arborizing in the distal and the proximal ipl, respectively. S2 cells were typified by their unstratified dendritic arbors. Similarly, S3 cells were characterised by their bistratified arbors. S5 cells arborized in the most proximal ipl sublamina. S6 cells were small ganglion cells with their somata lying in the inner nuclear layer. S7 cells tended to have complex dendritic arbors, and their axons arose from dendrites.
The facial “motor” nerve of the rat: Control of vibrissal movement and examination of motor and sensory components
Authors: Semba Kazue , Egger M. David 
Published: January 2005

AbstractRhythmical whisking of the mystacial vibrissae at about 7 Hz during exploration is one of the most conspicuous behavioral patterns in the rat. To identify the final common pathway for vibrissal movement, individual motor branches of the facial nerve, including the posterior auricular, temporal, zygomatic, buccal, marginal mandibular, cervical, stylohyoid, and posterior digastric branches, were cut, either singly or in various combinations. We found that vibrissal movement could be abolished only by transection involving the buccal branch and the upper division of the marginal mandibular branch.To trace back the central origins of the buccal and marginal mandibular, as well as the other branches of the facial nerve, all distal to the stylomastoid foramen, horseradish peroxidase (HRP) was applied to the cut proximal ends of these individual branches. The retrograde HRP labelling in the facial motor nucleus revealed topographical representation of these branches in which the buccal and marginal mandibular branches were represented laterally. The stylohyoid and posterior digastric branches originated from cells in the suprafacial nucleus. Consistent with earlier observations with intramuscular HRP injections, the motoneuronal population devoted to vibrissal movement did not seem to be substantially larger than that for other facial movements.An additional examination was made of the labelled afferent component of the facial motor nerve. We confirmed and extended previous findings that none of the above facial motor nerve branches, except the posterior auricular branch, contained a significant number of afferent fibers originating from the geniculate ganglion, the sensory ganglion of the seventh nerve. In addition, no labelling was seen in the mesencephalic trigeminal nucleus or trigeminal ganglion. These findings, in combination, suggest that, with the exception of the posterior auricular branch, all the facial motor nerve branches, including those involved in vibrissal movement, are almost entirely efferent.
The spinothalamic system of the rat. I. Locations of cells of origin
Authors: Granum Sherry L. 
Published: January 2005

AbstractHorseradish peroxidase retrograde transport has been used to locate neurons of the rat spinal cord and lower medulla that project to the thalamus. Eight groups of spinothalamic cells are identified, some of which are anatomically continuous with thalamically projecting groups in the lower medulla. Most of the groups are seen only at the highest cervical levels, and several of them have not been previously recognised as spinothalamic relays. They are marginal layer (M), ventral border of the substantia gelatinosa (SGv), neck of the dorsal horn (Nl), lateral cervical nucleus (LCN), ventromedial portion of the dorsal horn (DHvm), intermediate gray zone (IGZ), dorsal portion of the ventral horn (VHd), and ventral portion of the ventral horn (VHv). Most of the cell bodies are contralateral to their thalamic terminations; only the VHd group is ipsilateral.The major finding conflicts with traditional concepts of the spinothalamic system, and concerns the rostrocaudal distribution of the cells of origin. With the sole exception of the DHvm group, the great majority of the thalamically projecting neurons of the rat are confined to the most rostral spinal levels (medulla/cord junction through C4). Below C4, most of the spinothalamic cells are concentrated in a single DHvm group between levels T9 and L4, probably concerned with hindlimb proprioception.The spinothalamic groups at high cervical levels may be relays for information ascending from lower regions. This might help to explain why, in man, surgical destruction of fibres crossing the midline in a single high cervical segment can cause a loss of pain sensation over most of the body.
Immunohistochemical distribution of substance P, serotonin, and methionine enkephalin in sexually dimorphic nuclei of the rat lumbar spinal cord
Authors: Micevych Paul E. , Coquelin Arthur , Arnold Arthur P. 
Published: January 2005

AbstractThe purpose of the present study was to identify chemically some potential inputs to lumbar motoneurons of the rat in the spinal nucleus of the bulbocavernosus, ventral motor pool, dorsolateral nucleus, and retrodorsolateral nucleus. Substance P‐like immunoreactivity and serotonin‐like immunoreactivity were found in all four motor nuclei, with dense immunoreactive profiles surrounding motoneurons and their processes. Enkephalin‐like immunoreactivity was restricted to the sexually dimorphic nuclei, the spinal nucleus of the bulbocavernosus, and the dorsolateral nucleus. Within the spinal nucleus of the bulbocavernosus, enkephalin‐like immunoreactive profiles were apposed to the processes of motoneurons but not their somata. In contrast, enkephalin‐like immunoreactivity surrounded motoneuron somata in the medial part but not the lateral part of the dorsolateral nucleus, in the location of motoneurons projecting to the ischiocavernosus muscle. Moreover, the density of serotonin‐like immunoreactivity was also greater in the medial part of the dorsolateral nucleus. On the basis of the chemo‐architecture and the connections of the dorsolateral nucleus, we suggest the division of this motor column into a medial part composed of ischiocavernosus motoneurons surrounded by enkephalin‐ and serotonin‐like immunoreactivity and a lateral part that contains neurons that project to the sphincter urethrae muscle.Total spinal transection severely depleted both serotonin‐like and substance P‐like material in the lumbar ventral horn. No changes in the distribution of enkephalin‐like immunoreactivity were observed following this lesion. It is therefore suggested that in the ventral horn, substance P‐ and serotonin‐like material are derived from supraspinal tracts, whereas enkephalin‐like material is derived from intrinsic nerve cell bodies of the spinal cord.
A horseradish peroxidase study of the rubral and cortical afferents to the lateral reticular nucleus in the rat
Authors: Shokunbi M. T. , Hrycyshyn A. W. , Flumerfelt B. A. 
Published: January 2005

AbstractThe origin and organization of supraspinal afferents to the lateral reticular nucleus (LRN) in the rat were studied by means of the retrograde axonal transport of horseradish peroxidase (HRP). HRP was deposited into the LRN via both dorsal (stereotaxic) and ventral (microsurgical) routes. The entire cerebrum, brainstem, and cerebellum were surveyed for retrogradely labelled neurons. Significant projections arose from the contralateral red nucleus and the contralateral frontoparietal cortex.The rubral projection arose from neurons in the caudal two‐thirds of the red nucleus. Ventrally and ventrolaterally located neurons projected to rostrolateral LRN, while dorsal and dorsomedial neurons projected to rostromedial LRN. The projection from the cerebral cortex arose from neurons located in layer V of the frontoparietal region. Rubral and cerebrocortical projections overlap in the rostral LRN, making this region of the nucleus a site of integration of descending inputs with ascending spinal signals.
The distribution of tyrosine hydroxylase, dopamine‐β‐hydroxylase, and phenylethanolamine‐N‐methyltransferase immunoreactive neurons in the feline medulla oblongata
Authors: Reiner Peter B. , Vincent Steven R. 
Published: January 2005

AbstractThe distributions and morphological characteristics of neurons displaying immunoreactivity to the catecholamine synthetic enzymes tyrosine hydroxylase (TH), dopamine‐β‐hydroxylase (DBH), and phenylethanolamine‐N‐methyltransferase (PNMT) were examined in adjacent sections of the feline medulla oblongata. TH‐positive neurons were found in two bilaterally symmetrical columns in the ventrolateral and dorsomedial medulla. Within the ventrolateral medulla, TH‐positive neurons were found within the lateral reticular formation throughout the entire rostrocaudal extent of the medulla. In the dorsomedial medulla, TH‐immunoreactive perikarya were localized to the nucleus of the tractus solitarius including the commissural subnucleus, the dorsal motor nucleus of the vagus, and the area postrema. DBH‐positive neurons had distributions and morphologies similar to those of the TH‐immunoreactive cells with three exceptions: TH‐positive neurons far outnumbered DBH‐positive neurons in the area postrema; slightly greater numbers of TH‐positive neurons were seen in the commissural nucleus of the tractus solitarius; and, caudal to the obex, only TH‐positive neurons were seen within the dorsal motor nucleus of the vagus.PNMT‐immunoreactive neurons were found in all the nuclear regions of the medulla where both TH‐ and DBH‐positive neurons were seen. However, the PNMT immunoreactive perikarya had a somewhat more restricted distribution along the rostrocaudal axis. In the ventrolateral medulla, PNMT‐positive cells extended rostrally only as far as the retrofacial nucleus and caudally only to the obex. Within the dorsomedial medulla, PNMT immunoreactive cells were found from just rostral to the area postrema to the medullary‐spinal cord junction. These findings demonstrate that the distributions of TH, DBH, and PNMT immunoreactive perikarya in the medulla of the cat are generally similar to those seen in the rat insofar as these neurons are arranged in longitudinal columns in both species. However, significant differences exist with regard to the cytoarchitectonic borders within which immunoreactive perikarya can be found and the rostrocaudal extent of the PNMT‐positive cell groups in these two species.
Three‐dimensional structure of astrocytes in the rat dentate gyrus
Authors: Kosaka Toshio , Hama Kiyoshi 
Published: January 2005

AbstractStructural features of astrocytes in the rat dentate gyrus were studied by means of light and high‐voltage electron microscopy of Golgi‐impregnated materials, conventional electron microscopy, combined Golgi‐electron microscopy, and immunohistochemistry for glial fibrillar acidic protein.Astrocytes in the dentate gyrus were of the protoplasmic type and were classified into six subtypes based on the location of their somata: i.e., astrocytes 1) in the polymorph layer, (2) in the subgranular zone, (3) in the granular cell layer, (4) at the border of the granular cell layer and the molecular layer, (5) in the molecular layer, and (6) subjacent to the pia surface.Stereoscopic observations of 5‐μm‐thick sections of Golgi‐impregnated materials revealed three‐dimensional structural details of astroglial processes not apparent in either the light microscope or in conventional thinsection electron microscopy. Most of them were basically thin sheets, varying in shape and size in accordance with their sites. In the granule cell layer, thin veillike sheets or lamellae, originating from three kinds of astrocytes (subtypes 2, 3, and 4), intervened between granule cell somata, whereas in the plexiform and molecular layers small leafletlike appendages originating from astrocytes (subtypes 1, 2, 4, and 5) intermingled with one another, making spongelike conglomerates. Thus astrocytes in the subgranular zone and those at the border of the granule cell layer and the molecular layer showed prominent regional differentiation of their processes among layers. In addition to these sheetlike processes, thin threadlike processes were also common.
Anatomy and physiology of saccadic burst neurons in the alert squirrel monkey. I. Excitatory burst neurons
Authors: Strassman A. , Highstein S. M. , McCrea R. A. 
Published: January 2005

AbstractSaccadic burst neurons in the pontine reticular formation have been implicated in the generation of saccades in the horizontal plane on the basis of lesion and extracellular recording studies in the cat and monkey. In the present study, saccadic burst neurons were anatomically and physiologically characterized with intraaxonal recording and injection of horseradish peroxidase in the alert squirrel monkey. A population of burst neurons were found that appear analogous to the excitatory burst neurons (EBNs) described previously in the cat. All neurons are located in the caudal pontine reticular formation and have a major axonal projection to the ipsilateral abducens nucleus. Additional projections were found to the medial vestibular nucleus, the nucleus prepositus, and regions of the pontine and medullar reticular formation rostral, ventral, and caudal to the abducens. All neurons fire exclusively during saccades and have a discharge pattern similar to that of medium‐lead burst neurons described previously in the cat and monkey. In most neurons the saccadic burst begins 5‐15 msec before saccade onset. Linear relationships exist between burst duration and saccade duration, number of spikes in the burst and saccade amplitude, and firing frequency and instantaneous velocity. Physiological activity of each neuron shows the closest relationship with the amplitude of the saccade component in a particular direction. For all neurons, this on‐direction is in the ipsilateral hemifield and is predominantly horizontal, but may have either an upward or downward vertical component. These results support a major role for the EBNs in the monkey in generating the saccadic burst in abducens motoneurons, as well as in contributing to the oculomotor activity in other classes of premotor neurons.
Functional heterogeneity in the myenter is plexus: Demonstration using cytochrome oxidase as a verified cytochemical probe of the activity of individual enteric neurons
Authors: Mawe Gary M. , Gershon Michael D. 
Published: January 2005

AbstractThe cytochemical technique for the demonstration of cytochrome oxidase has been used to locate the sites of chronically active neurons in the CNS. The current experiments were undertaken to validate the use of this technique for the identification of active neurons and ganglia in the myenteric plexus of the gut. The excitotoxin veratridine was used to cause repetitive firing of action potentials and to depolarize myenteric neurons over an 8‐hour test period in vitro. The effects of veratridine were monitored electrophysiologically and correlated with the ability of the drug to affect the density of the cytochrome oxidase reaction product, as well as the proportion of reactive myenteric neurons. The action of veratridine on cytochrome oxidase activity was evaluated by means of video microdensitometry and computer‐assisted morphometry. Effects of veratridine were considered to be specific if they were blocked by the inclusion of tetrodotoxin (TTX), which antagonizes the action of veratridine on voltage‐dependent Na+ channels. Veratridine (1.0 μM) depolarized the membranes of myenteric type II neurons and greatly increased both the average density of the cytochrome oxidase reaction product in individual neuronal cell bodies and the proportion that were reactive. The concentration‐effect relationship for veratridine was biphasic. As the concentration of veratridine was raised, neurons became sufficiently depolarized such that they ceased to fire action potentials. This absence of spiking was associated with a decline in the stimulation of cytochrome oxidase activity by veratridine. At still higher concentrations of veratridine the degree of neuronal depolarization continued to increase. This further depolarization was associated with a secondary increase in cytochrome oxidase activity. All effects of veratridine were blocked by TTX. It is concluded that the cytochemical demonstration of cytochrome oxidase reflects the recent metabolic history and thus the physiological activity of myenteric neurons. In control preparations, fixed without exposure to veratridine, considerable variation in cytochrome oxidase was observed between ganglia and between individual neurons within ganglia. This suggests that there are significant differences in the activity of individual ganglia and neurons of the myenteric plexus. These observations support the hypothesis that there is a functional heterogeneity that corresponds to an anatomical heterogeneity (previously demonstrated) of the myenteric plexus.
Dopaminergic projection from nucleus raphe dorsalis to neostriatum in the rat
Authors: Descarries Laurent , Berthelet France , Garcia Sylvia , Beaudet Alain 
Published: January 2005

AbstractThe existence of a dopamine (DA) projection from nucleus raphe dorsalis (RD) to neostriatum was demonstrated in the rat by combined tyrosine hydroxylase (TH) immunohistochemistry and radioautography after retrograde axonal transport of [3H]noradrenaline ([3H]NA). Intrastriatal injections of [3H]NA were carried out in normal rats or after ipsilateral destruction of the nigrostriatal DA system by injection of 6‐hydroxydopamine (6‐OHDA) into the substantia nigra. Some 1,000 TH‐positive nerve cell bodies were counted within the confines of RD as defined by its content in serotonin (5‐HT) neurons. These DA neurons occupied the upper third of the RD and the, were part of its small cell population. In all cases, a small proportion of the TH‐immunoreaative nerve cell bodies in RD were retrogradely radiolabeled. Radiolabeled but immunonegative cells were exceedingly rare. The double‐labeled neurons were generally more numerous after elimination of the nigrostriatial DA innervation than in normal rats. They mostly lay within the ventral portion of the medial subdivision of RD and always predominated on the [3H]NA‐ injected side. Some were also present in nucleus linearis caudalis. It was concluded that (1) [3H]NA had been taken up and retrogradely transported exclusively by catecholamine neurons; (2) part of the DA cell group in RD projects to the neostriatum; and that (3) most if not all non‐5‐HT neurons projecting from RD to neostriatum are likely to be dopaminergic.
Anatomical and physiological observations on suprapinal control of bladder and urethral sphincter muscles in the cat
Authors: Holstege Gert , Griffiths Derek , De Wall Hans , Dalm Eddie 
Published: January 2005

AbstractIn 15 cats injections of 3H‐leucine were made in the pontine tegmentum. Injections in the medial part of the dorsolateral pontine tegmentum (M‐region) resulted in specific projections to the sacral intermediomedial and intermediolateral cell groups. The intermediolateral cell group contains preganglionic parasympathetic neurons that form the motor supply of the detrusor muscle of the bladder. Injections in the lateral part of the pontine tegmental field (L‐region) produced labeled fibers in the nucleus of Onuf, which contains motoneurons innervating the pelvic floor including the anal and urethral sphincters. L‐region projections to the sacral preganglionic parasympathetic neurons and M‐region projections to the nucleus of Onuf were very limited or absent.In 12 cats physiological experiments were performed. Electrical stimulation in the L‐region elicited a prompt increase in the pelvic floor EMG and urethral pressure but had little influence on the intravesical pressure. Stimulation in the M‐region elicited a prompt decrease in the pelvic floor EMG and urethral pressure followed, after a delay of 2 seconds, by an increase in the intravesical pressure, so simulating normal micturition.
The organization of the reciprocal connections between the subiculum and the entorhinal cortex in the cat: I. A neuroanatomical tracing study
Authors: van Groen T. , van Haren F. J. , Witter M. P. , Groenewegen H. J. 
Published: January 2005

AbstractThe connections between the subiculum (SUB) and the entorhinal cortex (EC) were studied in the cat with retrograde and anterograde tracing techniques.Injections of the retrogradely transported tracer WGA‐HRP at different levels along the septotemporal axis of the subiculum result in labeled neurons predominantly in the medial entorhinal cortex (MEA) in the superficial layers II and III. In the deep layers labeled cells are found more widespread over the EC. The superficially located labeled EC neurons are topographically distributed in a lateromedial gradient, which corresponds to a septotemporal gradient along the longitudinal axis of the subiculum. This organization of the EC‐SUB projection system could be substantiated by the use of injections anterogradely transported radioactively labeled amino acids in EC.The SUB to EC projections were investigated with the anterograde transport of WGA‐HRP and with radioactively labeled amino acids that were injected at different levels along the septotemporal axis of the subiculum. This results in a patch of anterogradely labeled fibers and terminals in MEA, predominantly in layers II and III, with a wider band of label in the deep layers. Again, a topographical distribution along the lateromedial axis of the EC corresponding to the septotemporal axis of the SUB was observed.Contralateral reciprocal connections between EC and SUB are also present, and exhibit a similar topographical organization.