bluuebunny/crossref_metadata_2025_split huggingface dataset:
Early development of serotonin‐containing neurons and pathways as seen in wholemount preparations of the fetal rat brain
Authors: Aitken Adrian R. , Törk Istvan 
Published: January 2005

AbstractThe early development of serotonin‐containing neurons was studied in wholemounts of the fetal rat brain (E12–E18). The wholemounts were treated immunocytochemically according to an immunoperoxidase technique to reveal a panorama of developing serotoninergic neurons. Serotoninergic neurons were localized to two discrete groups or clusters within the brainstem. Serotonin‐containing neurons were identified first at E12 forming a rostral cluster of cells just caudal to the mesencephalic flexure. The more caudal cluster of cells first appeared at E14 in the medulla. During the period from E12 to E18, the immunoreactive cells increased in number and acquired a more complex dendritic tree while migrating to their permanent position. At E16, cells of the rostral group exhibited remarkably uniform mediolateral orientation.The rostral group of immunoreactive neurons gave rise to almost all ascending fibers, whereas the caudal group gave rise to the majority of descending fibers. Growing serotoninergic fibers were tipped by prominent growth cones, which were strongly immunoreactive. The fibers demonstrated prominent orientational selectivity with an almost total separation into ascending and descending bundles. Some of the ascending immunoreactive fibers displayed acute changes in their direction of growth, suggesting that the orientation of serotininergic fibers is mediated by directional cues that are specific to particular populations of serotoninergic fibers. Serotoninergic axons within the medial forebrain bundle were demonstrated particularly well and their ascent and rate of growth toward the forebrain could be easily followed. Immunoreactive fibers entered the telencephalon at E17 two portals, one along the lateral border of the hypothalamus and one rostrally, adjacent to the olfactory tubercle. In wholemounts at E18, fibers arising from this latter location could be followed as two distinct bands within the pallium; a basal band located ventrolaterally, adjacent to the lateral olfactory tract, and a dorsal band located at the medial edge of the telencephalon. Both fascicles were directed toward the occipital pole and contained unbranched fibers. At E18, serotoninergic axons arising from these two loosely organized fascicles covered most of the frontal telencephalon.The results of the present study indicate that wholemounts of embryonic brain can provide novel spaciotemporal data on the development of neuro‐transmitter systems and may in the future prove to be useful experimental preparations in developmental neurobiology.
Neonatal infraorbital nerve transection in rat results in peripheral trigeminal sprouting
Authors: Chiaia Nicolas L. , Allen Zebetta , Carlson Eric , MacDonald Gordon , Rhoades Robert W. 
Published: January 2005

AbstractRetrograde tracing techniques were employed to determine whether transection of the infraorbital (IO) nerve in either newborn or adult rats resulted in peripheral sprouting by undamaged trigeminal (V) axons. The IO nerve was sectioned just behind the vibrissa pad, either on the day of birth or when animals reached at least 60 days of age. After an additional 60 days, the same nerve was retransected in the orbit; horseradish peroxidase (HRP) or diamidino yellow (DY) was injected into the central portion of the vibrissa pad; and animals were killed 2–3 days later. In the neonatally nerve‐damaged rats, this procedure invariably labelled primary afferent neurons in both the ipsilateral and contralateral V ganglia. On the ipsilateral side, these cells were located in the caudal portion of the ophthalmicmaxillary region and, less often, in the mandibular division. Their average diameter was 22.6 μm (s.d.=5.6). On the contralateral side, most labelled ganglion cells were visible in the anteromedial part of the ophthalmicmaxillary region but a few could also be seen in the mandibular division. Their average diameter was 21.1 μm (s.d.=5.5). No labelled ganglion cells were observed in adult rats subjected to the same series of manipulations.In a separate series of neonatally nerve‐damaged animals, the above‐described procedures were combined with neonatal injection of capsaicin in an effort to determine whether the observed sprouting was dependent upon the presence of large numbers of unmyelinated axons. The addition of this treatment reduced the number of labelled cells in both the ipsilateral and contralateral ganglia, but it did not alter either their distribution or average soma diameter.In a final experiment, sequential double‐labelling techniques were used to determine whether the V axons that projected to the vibrissa pad via non‐IO nerve branches were the result of sprouting by undamaged ganglion cells or arose from neurons that had originally projected into the IO nerve, were axotomized by our lesions, and regenerated to the vibrissa pad via another V branch. Here, the long‐lived retrograde tracer true blue (TB) was injected into the vibrissa pad 6–8 hours before the neonatal nerve cut and DY was deposited into the pad after transection of the regenerate IO nerve in adulthood. Double‐labelled cells in this experiment would have projected to the vibrissa pad via the IO nerve at birth and regenerated to it via another V branch in adulthood. Nearly 55% of the DY‐labelled cells in this experiment also contained TB. This result indicated that about one‐half of the innervation of the vibrissa pad by non‐IO V branches was the result of axonal sprouting by undamaged ganglion cells.
Quantitative study of granule and Purkinje cells in the cerebellar cortex of the rat
Authors: Harvey R. J. , Napper R. M. A. 
Published: January 2005

AbstractThe numerical densities of granule and Purkinje cells in the cerebellar cortex of the rat were determined by stereological methods. The density of Purkinje cells in our fixed material was 1,018 ± 39 per mm2 (mean ± s.e.m.) of Purkinje cell layer and that of granule cells 1.92 ± 0.03 × 106 per μl of granular layer. The total area of Purkinje cell layer was 332 mm2 and the volume of granular layer was 48 μl. The rat cerebellum therefore contains 3.38 × 105 Purkinje cells and 9.2 × 107 granule cells, from which there are 274 granule cells for each Purkinje cell. The density of granule cells and the density of parallel fibers in the molecular layer observed in a companion study indicate that the average length of a parallel fiber is around 5 mm.
Projections of nucleus angularis and nucleus laminaris to the lateral lemniscal nuclear complex of the barn owl
Authors: Takahashi Terry T. , Konishi Masakazu 
Published: January 2005

AbstractInteraural phase and intensity are cues by which the barn owl determines, respectively, the azimuth and elevation of a sound source. Physiological studies indicate that phase and intensity are processed independently in the auditory brainstem of the barn owl. The phases of spectral components of a sound are encoded in nucleus magnocellularis (NM), one of the two cochlear nuclei. NM projects solely and bilaterally to nucleus laminaris (NL), wherein interaural phase difference is computed. The other cochlear nucleus, nucleus angularis (NA), encodes the amplitudes of spectral components of sounds. We report here the projections of NA and NL to the lateral lemniscal nuclei of the barn owl.The lateral lemniscal complex comprises nucleus olivaris superior (SO); nucleus lemnisci lateralis, pars ventralis (LLv); and nucleus ventralis lemnisci lateralis (VLV). At caudal levels, VLV may be divided into a posterior (VLVp) and an anterior (VLVa) subdivision on cytoarchitectonic grounds. At rostral levels, the cytoarchitectural differences diminish and the boundaries between the two subdivisions become obscured. Likewise, our data from anterograde tracing studies suggest that at caudal levels the terminal fields of NA and NL remain confined to VLVp and VLVa, respectively. They merge, however, at rostral levels. The data also suggest that NL projects to the medial portion of the ipsilateral SO and that NA projects bilaterally to all parts of SO and LLv. Studies with the retrograde transport of horseradish peroxidase confirm these projections.
Spinocerebellar projections from the lowest lumbar and sacral‐caudal segments in the cat, as studied by anterograde transport of wheat germ agglutinin‐horseradish peroxidase
Authors: Matsushita Matsuo 
Published: January 2005

AbstractThe projection fields of spinocerebellar tracts arising from the lowest lumbar and sacral‐caudal segments were studied by the anterograde transport of wheat germ agglutinin conjugated to horseradish peroxidase (WGA‐HRP) in the cat.Injections of WGA‐HRP into these segments labeled mossy fiber terminals mainly in sublobules Ia‐Vf, lobule VI, and sublobules VIIb‐VIIIb. In the sagittal plane the labeled terminals were distributed in the apical part of the lobules. MOre than 90% of the total number were in the anterior lobe, of which 50–80% were in sublobules IIa and IIb. The labeled terminals were concentrated between 1.0 and 2.0 mm lateral to the midline. The results of injections following hemisections revealed that the projections are bilateral and that their quantity does not differ between the two sides. The projection fields in the horizontal plane were reconstructed from a series of cross sections through lobules I–III. The labeled terminals were distributed in two areas localized to the apical part of the lobules: area 1 located between 0.75 and 1.5 mm lateral to the midline in zone B of Voogd (the lateral part of the vermis) and area 2 located 2.0 mm lateral to the midline in zones C1–C3 (the intermediate region of the hemisphere).The present anterograde and previous retrograde HRP studies show that the spinocerebellar tract neurons in the medial part of lamina VII caudal to the L7 segment and in laminae V and VIII of sacral‐caudal segments project mainly to lobules I–V of the anterior lobe and to lobule VI, sublobule VIIb, and lobule VIII of the posterior lobe. The projections were most abundant in sublobules IIa and IIb.
Ascending projections from the pedunculopontine tegmental nucleus and the adjacent mesopontine tegmentum in the rat
Authors: Hallanger Ann E. , Wainer Bruce H. 
Published: January 2005

AbstractAscending projections from the pedunculopontine tegmental nucleus (PPT) and the surrounding mesopontine tegmentum to the forebrain in the rat are here examined by using both retrograde and anterograde tracing techniques combined with choline acetyltransferase (ChAT) immunohistochemistry. The anterogradely transported lectin Phaseolus vulgaris‐leukoagglutinin (PHA‐L) was iontophoretically injected into the PPT in 12 rats. Anterogradely labelled fibers and varicosities were observed in the thalamic nuclei, confirming the findings of our previous retrograde studies (Hallanger et al: J. Comp. Neurol. 262:105–124, ′87). In addition, PHA‐L‐labelled fibers and varicosities suggestive of terminal fields were observed in the anterior, tuberal, and posterior lateral hypothalamic regions, the ventral pallidum in the region of the nucleus basalis of Meynert, the dorsal and intermediate lateral septal nuclei, and in the central and medial nuclei of the amygdala.To determine whether these were cholinergic projections, the retrograde tracer WGA‐HRP was injected into terminal fields in the hypothalamus, septum, ventral pallidum, and amygdala. Numerous ChAT‐immunoreactive neurons in the PPT and laterodorsal tegmental nucleus (LDT) were retrogradely labelled from the lateral hypothalamus. These cholinergic neurons constituted over 20% of those retrogradely labelled in the dorsolateral mesopontine tegmentum; the balance consisted of noncholinergic neurons of the central tegmental field, retrorubral field, and cuneiform nucleus. Following placement of WGA‐HRP into dorsal and intermediate lateral septal regions, the vast majority (> 90%) of retrogradely labelled neurons were cholinergic neurons of the PPT and LDT, with few noncholinergic retrogradely labelled neurons in the adjacent tegmentum. In contrast, fewer cholinergic neurons were retrogradely labelled following placement of tracer into the nucleus basalis of Meynert or into the central, medial, and basolateral nuclei of the amygdala, while numerous noncholinergic neurons of the central tegmental field rostral to the PPT and of the retrorubral field adjacent to the PPT were retrogradely labelled in these cases. These anterograde and retrograde studies demonstrate that cholinergic PPT and LDT neurons provide a substantial proportion of mesopontine tegmental afferents to the hypothalamus and lateral septum, while projections to the nucleus basalis and the amygdala are minimal.
Immunohistochemical localization of substance P, somatostatin, enkephalin, and serotonin in the spinal cord of the northern leopard frog, Rana pipiens
Authors: Adli Durriyyah S. H. , Rosenthal Bennett M. , Yuen Geoffrey L. , Ho Raymond H. , Cruce William L. R. 
Published: January 2005

AbstractUsing the indirect antibody peroxidase‐antiperoxidase method of Sternberger, we localized substance P (SP), somatostatin (SOM), enkephalin (ENK), and serotonin (5HT, 5‐hydroxytryptamine) in the spinal cord of Rana pipiens. This is the first study to demonstrate all four substances in adjacent sections of frog spinal cord. The distribution patterns of ENK, SP, SOM, and 5HT in our study differ from that described for laminae I and II in amniotes. A high density of ENK, SP, and SOM fibers is present in a band ventral to the dorsal terminal field of cutaneous primary afferent fibers and slightly overlapping the ventral terminal field of muscle primary afferent fibers. However, a high density of 5HT fibers is present in the dorsal terminal field.
Acute and chronic effects of the neurolytic agent ricin on dorsal root ganglia, spinal cord, and nerves
Authors: Pubols Lillian M. , Foglesong Mark E. 
Published: January 2005

AbstractThe short– and long–term effects of ricin injections into nerves have been evaluated with light microscopy in the dorsal root ganglia, spinal cord, and peripheral nerves in rats and cats. Dorsal root ganglion cells initially exhibited chromatolysis, followed by gliosis and cell death. These changes were associated with Fink‐Heimer degeneration in the somatotopically appropriate region of the dorsalhorn. There were no signs of chromatolysis in dorsal horn neurons in ricin‐injected animals, but chromatolytic motoneurons were observed. Ricin produced acute necrosis of injected nerves and dissolution of axoplasm. At long survival times (4 weeks) some apparently regenerating axons were seen in the injection sites of rats. Cell counts indicated that a substantial percentage of dorsal root ganglion neurons associated with the injected nerves were killed, but the presence of regenerating axons suggested that some cells survived the ricin treatment. Although the lesion may not always be complete, even with maximum sublethal doses, this method appears to be useful for specifically destroying afferent fibers associated with a particular nerve without transynaptic destruction of dorsal horn neurons.
Cholinergic vs. noncholinergic efferents from the mesopontine tegmentum to the extrapyramidal motor system nuclei
Authors: Lee Henry J. , Rye David B. , Hallanger Ann E. , Levey Allan I. , Wainer Bruce H. 
Published: January 2005

AbstractPrevious studies have suggested that the pedunculopontine tegmental nucleus (PPTn) is reciprocally connected with extrapyramidal motor system nuclei (EPMS) whereas other studies have implicated the PPTn in behavioral state control phenomena such as sleep‐wakefulness cycles. Many of these studies define the nonprimate PPTn as an area of mesopontine tegmentum which is labeled from injections of anterograde tracers into the basal ganglia. Recently, we have defined the rat PPTn as a large‐celled, cholinergic nucleus. The rat PPTn is cytologically distinct from a group of smaller, noncholinergic neurons that are medially adjacent to the PPTn. This noncholinergic group is further distinguished from the PPTn by its afferent input from the globus pallidus, entopeduncular nucleus, and substantia nigra. We refer to the latter area as the midbrain extrapyramidal area (MEA).Using combined choline acetyltransferase immunohistochemistry of the PPTn and WGA‐HRP retrograde tracing from the EPMS, we investigated the efferent connections of the MEA and PPTn to the EPMS in the rat. The noncholinergic MEA, rather than the PPTn, is the major source of tegmental innervation to the globus pallidus, caudate‐putamen, subthalamic nucleus, entopeduncular nucleus, substantia nigra, and motor cortex. In contrast, the cholinergic PPTn is the major source of tegmental innervation to the ventrolateral thalamic nucleus. This finding is in contradistinction to thalamic projections from the surrounding reticular formation, which are identified only after WGA‐HRP injections into “nonspecific” thalamic nuclei. This body of evidence suggests that the noncholinergic MEA represents an additional component of the EPMS and may correspond to the “mesencephalic locomotor region.” The cholinergic PPTn may play a role in more global thalamic functions such as the “reticular activating system” rather than a primary role in motor function.
Feline islands of calleja complex: II. Cholinergic and cholinesterasic features
Authors: Talbot Konrad , Woolf Nancy J. , Butcher Larry L. 
Published: January 2005

AbstractHistochemical analyses demonstrated that the islands of Calleja complex (ICC) in the cat is exceptionally rich in choline acetyltransferase (ChAT) and acetylcholinesterase (AChE). Both enzymes are found in neuropil throughout the complex, as well as in a subset of the satellite neurons accompanying Callejal islands. Lateromedial changes in these cholinergic and cholinesterasic tissue elements were consistent with our previous finding that the feline ICC is cytoarchitecturally divided into five successively more medial types of island‐satellite cell ensembles or units. In particular, satellite neurons reactive for ChAT and AChE diminished progressively in size and increased steadily in number from the most lateral to the most medial units. A concomitant increase in neuropil levels of both enzymes suggested that the strong cholinergic innervation of the feline ICC is at least partially derived from satellite cells. This possibility gained further credibility from the additional observation that very fine processes from some ChAT and AChE satellite neurons projected into the terminal‐like cholinergic field permeating the granular Callejal islands. The granule cells themselves lacked ChAT and (apart from potentially artifactual cases) AChE, as did adjoining groups of dwarf cells and small pyramidal like neurons.The cholinergic and cholinesterasic satellite neurons were preferentially located above tubercular Callejal islands and in otherwise cell‐poor spaces within the isla magna. Such neurons appeared to be isodendritic: they commonly had ovoidal somata with one or two processes lacking enzyme‐reactive spines. Depending on the type of ICC unit involved, their mean soma length ranged from 15 to 24 μm, all but the largest of which was distinctly smaller than that of ChAT and AChE cells in striatal or basal nuclear structures. Not all the cholinesterase neurons in the feline ICC are cholinergic, judging from the finding that there are a significantly greater number of satellite neurons containing AChE than ChAT.Three cholinergic features of the feline ICC are especially noteworthy. First, each of the island‐satellite cell ensembles in the complex is unified by AChE neuropil often denser than that of adjacent striatal areas. Second, cholinergic neuropil is exceptionally dense in the isla magna and in a subpial band under medial Callejal islands. Third, ChAT neurons in the isla magna are among the smallest cholinergic cells found in the brain.
Cytoarchitectonic analysis of the SDN‐POA of the intact and gonadectomized rat
Authors: Bloch G. J. , Gorski R. A. 
Published: January 2005

AbstractThe densely staining group of cells referred to as the sexually dimorphic nucleus of the preoptic area (SDN‐POA) is greater in volume in the male than in the female rat. Because we and others have reported absolute volumes that have been consistent within individual studies but that vary considerably, we characterized the SDN‐POA by describing its morphology with respect to the cytoarchitectonic divisions of the medial preoptic nucleus (MPN) in intact and gonadectomized rats. We report three major findings: the SDN‐POA is heterogeneous and is composed of cells belonging to three distinct cytoarchitectonic divisions; the cytoarchitecture of the MPN and its medial and lateral divisions (MPNm and MPNl, respectively) in male rats appear to be influenced by the hormonal status in adulthood; and a small anteroventral division of the MPN (MPNav) is present in males but virtually absent in females. Specifically, the SDN‐POA is located within the MPNm, but consists of subcomponents located within the central division of the MPN (MPNc), the MPNav, and part of the MPNm‐exclusive of the MPNc and MPNav. The percentage of the total SDN‐POA located within the MPNc and MPNav was greater in males, and that in the MPNm‐exclusive of the MPNc and MPNav was greater in females, indicating that the SDN‐POA has a different cytoarchitectonic composition in the two sexes. Gonadectomy produced no significant differences in SDN‐POA volume, but the MPN, MPNl, and MPNm were significantly reduced in gonadectomized versus intact males, suggesting an activational effect of testicular hormones on these structures.