bluuebunny/crossref_metadata_2025 huggingface dataset:
Immunoreactivity in Limulus: III. Morphological and biochemical studies of FMRFamide‐like immunoreactivity and colocalized substance P‐like immunoreactivity in the brain and lateral eye
Authors: Lewandowski Thomas J. , Lehman Herman K. , Chamberlain Steven C.
Published: January 2005

FMRFamide‐like immunoreactivity (FLI) and the colocalization of FMRFamide and subtance P‐like (SPLI) immunoreactivities were examined in the brain and lateral eye of the horseshoe crab with FITC‐ and TRITC‐ labeled secondary antibody techniques. In the brain, fibers with FLI were localized in the neuropils of the lamina, medulla, central body, corpus pedunculatum, optic tract, circumesophageal connective, and central neuropil. An extensive network of reactive fibers innervates the brain's vascular sheath. Somata with FLI were found in the dorsal medial group, dorsal lateral posterior groups #1 and #2, and ventral posterior lateral groups #1 and #2. Several distinct subgroups of reactive somata were noted in both the medullar and ventral medial groups.

The distribution of fibers in the brain with colocalized FLI and SPLI includes those which innervate the vascular sheath and widespread populations of small‐diameter beaded fibers in the central neuropil and circumesophageal connective. Somata with colocalized FLI and SPLI constitute minority populations in the medullar and dorsal medial groups but form the majority population of a subgroup in the ventral medial group.

Overall localization of SPLI was reevaluated and is reported here according to the nomenclature of the new Chamberlain and Wyse brain atlas. In addition to those previously reported, somata with SPLI were found in the dorsal lateral posterior groups #1 and #2, the ventral lateral posterior groups #1 and #2, and several distinct subgroups of the medial and ventral medial groups.

In the retina of the lateral eye, fibers with both FLI and SPLI ramify in the lateral plexus and ultimately innervate the corneal epidermis.

Brain homogenates were examined for immunoreactive (ir) FMRFamide and ir–substance P with radioimmunoassay techniques. Ir‐FMRFamide and ir–substance P eluted in different fractions from both gel filtration chromatography and HPLC. Furthermore, the binding curves for both substances were similar to those of the corresponding synthetic compounds.

Brain homogenates were also bioassayed on the lateral eye. Three gel filtration fractions mimic natural circadian activity by increasing the sensitivity of the lateral eye, but they were not coincident with ir‐FMRFamide or ir–substance P. Although it is not completely resolved what the active molecules in these fractions are, it is clear that neither ir‐FMRFamide nor ir–substance P is a possible candidate.
Serotonin immunoreactivity in the optic lobes of the sphinx moth Manduca sexta and colocalization with FMRFamide and SCPB immunoreactivity
Authors: Homberg U. , Hildebrand J. G.
Published: January 2005

In the optic lobes (OLs) of the sphinx moth Manduca sexta, 300–350 neurons per hemisphere are immunoreactive with an antiserotonin antiserum. Two groups of weakly serotonin‐immunoreactive cells (OL1) appear to be amacrine cells of the medulla, whereas more intensely immunoreactive cells (OL2) are probably centrifugal neurons that innervate the lobula, medulla, and lamina, as well as the superior protocerebrum. At least one other OL2 cell is a local optic‐lobe interneuron with arborizations in the dorsal medulla and lobula. The serotonin‐immunoreactive cells are also immunoreactive with an antiserum against Drosophila melanogaster DOPA decarboxylase. All OL2 cells, but not the OL1 cells, are furthermore immunoreactive with an anti‐FMRFamide antiserum and an anti‐SCPB antiserum. This suggests that neuropeptides related or identical to FMRFamide and SCPB are colocalized and may serve as cotransmitters with serotonin in OL2 optic‐lobe interneurons.
Organization of afferent and efferent pathways in the pudendal nerve of the female cat
Authors: Thor K. B. , Morgan C. , Nadelhaft I. , Houston M. , de Groat W. C.
Published: January 2005

Application of horseradish peroxidase to the pudendal nerve in the female cat labelled lumbosacral afferent and efferent neurons and their processes. Afferent axons entered the spinal cord primarily at the S1 and S2 segments and traveled rostrocaudally in Lissauer's tract and the dorsal columns. A distinctive component of the dorsal column projection was located at the lamina I‐dorsal column border as a densely labelled, compact bundle that distributed fibers to the dorsal horn at spinal levels near the segments of entry of the afferent axons. Afferent terminal labelling was located in the marginal zone, the intermediate gray matter, and the dorsal gray commissure in the lumbosacral and coccygeal spinal cord. A well‐defined terminal field restricted to the S1 and rostral S2 segments was present in the medial third of the nucleus proprius and substantia gelatinosa. Labelled motoneurons in Onuf's nucleus (S1 and S2) exhibited longitudinal dendrites that extended rostrocaudally within the nucleus and three groups of transverse dendrites that emanated periodically from the nucleus and passed to the ventrolateral funiculus, the intermediate gray, and the dorsal gray commissure. Components of the pudendal nerve that innervate the anal and urethral sphincters were also labelled by injecting HRP into the respective sphincter muscles. Motoneurons innervating the anal and urethral sphincters were located in the dorsomedial and ventrolateral divisions, respectively, of Onuf's nucleus. Afferent projections from the two sphincters were similar; the most prominent terminations were present in the marginal zone, intermediate gray, and dorsal gray commissure. These results are discussed with respect to the physiological function of the pudendal nerve and its relationship with sacral autonomic pathways.
Primate spinothalamic pathways: II. The cells of origin of the dorsolateral and ventral spinothalamic pathways
Authors: Apkarian A. Vania , Hodge Charles J.
Published: January 2005

The cells of origin of the dorsolateral (DSTT) and the ventral (VSTT) spinothalamic tracts were studied in 11 monkeys. The spinothalamic tract cells were retrogradely labeled by horseradish peroxidase (HRP) injected in the thalamus. All animals also received a midthoracic spinal cord lesion on the side ipsilateral to the thalamic injections.

The distribution of labeled cells found in these animals throughout the cervical segments was similar to animals with no spinal cord lesions. Five animals had ventral quadrant lesions to demonstrate the cells of origin of the DSTT. In macaques with complete ventral quadrant lesions, more than 80% of the HRP label in the contralateral L4–L7 segments was located in lamina I, while in squirrel monkeys, the label in the contralateral lower lumbar region was distributed between laminae I–III and IV–VI. Few labeled cells were found in laminae VII–X.

Six animals received dorsolateral funiculus lesions to demonstrate the cells of origin of the VSTT. In animals with adequate lesions, 84–99% of the contralateral HRP label in L4–L7 was located in laminae IV–X. Macaques had a larger percentage of labeled cells located in lamina I than squirrel monkeys.

The results indicate the existence of two spinothalamic pathways in the primate. The DSTT was calculated to compose about one fourth of the total spinothalamic population.
Novel peptide pancreastatin: Its occurrence and codistribution with chromogranin a in the central nervous system of the pig
Authors: Kar S. , Bretherton‐Watt D. , Gibson S. J. , Steel J. H. , Gentleman S. M. , Roberts G. W. , Valentino K. , Tatemoto K. , Ghatei M. A. , Bloom S. R. , Polak J. M.
Published: January 2005

The distribution of pancreastatin immunoreactivity was investigated in porcine brain, spinal cord, dorsal root ganglia, and pituitary. In the brain, immunoreactive cell bodies were present in many areas including the cortex, basal ganglia, hippocampus, thalamus, hypothalamus, mesencephalic reticular formation, cerebellum, and medulla oblongata. Immunoreactive fibres were most abundant in the globus pallidus, stria terminalis, entopeduncular nucleus, hippocampus, and in the substantia nigra. In the spinal cord, immunoreactive cells were found in laminae IV±IX. Immunoreactive fibres were concentrated in the dorsal horn. Pancreastatin immunoreactivity was localised to fibres and small cells (5–10% of the total) in the dorsal root ganglia. In the posterior pituitary, many immunoreactive fibres were present and in the anterior lobe subsets of gonadotrophs and thyrotrophs were pancreastatin‐immunoreactive. The localisation of pancreastatin showed a parallel distribution with chromogranin A. Coexistence of pancreastatin with calcitonin generelated peptide (CGRP) immunoreactivity in cell bodies in the spinal cord, including motoneurones, and with CGRP or galanin immunoreactivities in dorsal root ganglion cells was also noted. The differential pattern of pancreastatin immunostaining was reflected in the extractable levels of peptide with highest concentrations in the cortex (55.8 ± 6.0 pmol/g wet weight, mean ± S.E.M.), thalamus (60.0 ± 5.0 pmol/g), hypothalamus (54.4 ± 6.5 pmol/g), and anterior pituitary (2,714 ± 380 pmol/g). Characterisation of pancreastatin immunoreactivity in the hypothalamus and pituitary by gel permeation and high‐pressure liquid chromatography revealed multiple molecular forms, one of which was indistinguishable from natural porcine pancreastatin. The widespread distribution of pancreastatin immunoreactivity suggests this peptide may play a part in several neuroendocrine, autonomic, somatic, and sensory functions, and its colocalisation with chromogranin A is consistent with a precursor‐product relationship.
Number and size of neurons and synapses in the motor cortex of cats raised in different environmental complexities
Authors: Beaulieu Clermont , Colonnier Marc
Published: January 2005

In a previous study we have shown that the richness of the environment affects the number of neurons, the size of their nuclei, the number of round‐asymmetrical synapses per neuron, the numerical density (number per unit volume; Nv) of flat‐symmetrical synaptic contacts, their number per neuron and their size in the visual cortex of cats. Of these, the number of flat‐symmetrical synapses per unit volume is particularly affected (there are nearly twice as many per mm3 in the impoverished cortex). Several studies in the rat have shown that environmentally induced changes in cortical thickness occur in the occipital regions but are much smaller or absent in the frontal regions. In order to determine if the cat motor cortex is also resistant to environmental changes, we have estimated the number and size of neurons and of synapses in individual laminae of motor cortex, area 4γ, in six pairs of cats raised either in a colony (EC: enriched condition) or in isolation (IC: impoverished condition).

For the neurons, we have found that the numerical density (28,900 neurons per mm3 of EC and 29,500 neurons/mm3 of IC motor cortex), the number under 1 mm2 of cortical surface (49,400 and 49,200 in EC and IC cats), and the size of the neuronal nuclei (82 vs 80 μm2 in EC and IC animals) were not significantly affected.

The number of flat‐symmetrical synapses per neuron (1,470 in EC vs 1,400 in IC cortex), their size (0.33 μm in both groups) and even their number per unit volume, which was so greatly affected in the visual cortex, remains unchanged (43 million/mm3 and 41 million/mm3 in EC and IC motor cortex). We did find however, a significant difference (p < 0.05) in the numerical density of round‐asymmetrical synapses which is 13% greater in the impoverished motor cortex (216 million/mm3 in EC vs 247 million/mm3 in IC cortex).

Our results confirm that the motor cortex is much less affected by the richness of the environment than the visual cortex: In fact, the cat motor cortex is hardly affected at all. Furthermore our results represent the most complete data presently available on the number and size of neurons and synapses in individual laminae of the cat motor cortex.
Cells in laminae III and IV of rat spinal dorsal horn receive monosynaptic primary afferent input in lamina II
Authors: Todd Andrew J.
Published: January 2005

In order to determine how information conveyed by fine primary afferent fibres might reach the deeper laminae of the spinal dorsal horn, 5 Golgistained neurones with somata in lamina III or IV and dendrites that entered lamina II were examined by electron microscopy.

Three of the cells were from animals in which 2 or 3 dorsal roots had been cut 26 or 30 hours previously. These cells received numerous synapses in lamina II, and between 13 and 16% of these (24–31% of asymmetric synapses) were from degenerating axons. Synapses with degenerating axons were found throughout the depth of lamina II, including the dorsal part, which receives primary afferent input from myelinated nociceptors and from unmyelinated axons. In addition, all 3 cells were postsynaptic to degenerating axons within lamina III. The 2 cells from unoperated animals also received many synapses within lamina II and at some of these the presynaptic axon was the central terminal of a glomerulus. Only one example of a dendrodendritic synapse involving a stained dendrite was seen. Cells of laminae III and IV may therefore not be a major target for presynaptic dendrites of cells in lamina II.

It is concluded that one way in which information carried by primary afferents passes from the superficial dorsal horn to the deeper laminae is through monosynaptic contacts between these afferents and the dorsal dendrites of some cells whose somata are situated in laminae III and IV. If the axons of these cells generate local collaterals, this may account for some of the activation of cells whose dendrites do not enter lamina II.
Auditory cortical projection from the anterior ectosylvian sulcus (Field AES) to the superior colliculus in the cat: An anatomical and electrophysiological study
Authors: Alex Meredith M. , Ruth Clemo H.
Published: January 2005

Sensory activity in the deep layers of the superior colliculus (SC) is strongly influenced by descending cortical inputs. Elimination (permanent or reversible) of specific regions of visual or somatosensory cortex, known to have direct access to the SC, abolishes or dramatically reduces SC responses to stimuli from those modalities. While many SC neurons are also responsive to auditory cues, the origin of auditory corticotectal connections is not clear at present and their affect on activity in the SC is unknown. Therefore, the present study was undertaken to determine the origin, organization, and functional characteristics of auditory corticotectal projections. Of the auditory cortices (AI; AII; Fields A, P, and VP), only the auditory subregion of the banks of the anterior ectosylvian sulcus (Field AES) showed a robust anatomical projection to the SC. These data were confirmed physiologically: auditory neurons in Field AES projected to the SC and auditory SC neurons responded to stimulation of the Field AES. However, neither anatomical nor physiological techniques revealed a clear topographic relationship between the Field AES and the SC but suggested instead a diffuse and extremely divergent/convergent projection. Stimulation and cryoblockade of Field AES demonstrated the excitatory nature of this corticotectal pathway, whose influence was most evident on SC responses to stimuli of reduced intensity. Given the short latency of this ear‐cortex‐SC circuit and its excitatory influence on unimodal as well as on multisensory auditory neurons, it seems likely that Field AES plays a significant role in facilitating SC responses to auditory stimuli.
Expression of the growth cone specific epitope CDA 1 and the Synaptic vesicle protein SVP38 in the developing mammalian cerebral cortex
Authors: Devoto Stephen H. , Barnstable Colin J.
Published: January 2005

CDA 1 is a novel antigen that within the brain is present specifically in neuronal growth cones. Electron microscope immunohistochemistry and subcellular fractionation showed the CDA 1 epitope to be on a cytosolic molecule. In cultured neurons, it is abundant in growth cones and not detectable in neurites or cell bodies.

The development of the rat cerebral cortex was investigated by using the monoclonal antibody to CDA 1 and an antibody to SVP38, the synaptic vesicle glycoprotein. CDA 1 immunoreactivity in the rat cerebral cortex peaks just before birth and disappears by postnatal day 12, a few days before the major increase in the number of mature synapses. In contrast, SVP38 is expressed in parallel with the appearance of mature synapses. CDA 1 and SVP38 thus are markers of growth cones and synapses, respectively. Their expression during development reflects some of the structural and functional changes that occur during synapse formation.
New structural features of synapses in the anteroventral cochlear nucleus prepared by direct freezing and freeze‐substitution
Authors: Tatsuoka Hozumi , Reese Thomas S.
Published: January 2005

The rostral anteroventral cochlear nucleus (AVCN) of the chinchilla provides a preparation in which neuronal cell bodies and synapses in the mammalian central nervous system can be examined after direct freezing and freeze‐substitution of rapidly excised brain stem slices. Cell bodies and synapses in the freeze‐substituted AVCN differed from those in perfusion‐fixed AVCN in several interesting respects. Despite of these differences, four types of synaptic terminal were distinguished in freeze‐substituted AVCN and correlated with the four well‐known types of perfusion‐fixed terminal. Since the transmitter at each of the four types of terminal has been tentatively identified, the structure of synaptic vesicles and junctions in the freeze‐substituted terminals could be related to transmitter type. Synaptic vesicles were uniformly round, but their diameters, deployment, and related cytoskeletal elements near the synaptic junction differed in each chemical type of synapse; the synapses thought to be cholinergic, for instance, had only a few vesicles clustered at their presynaptic junctions while the rest of the vesicles were separated from the junction by a network of fine filaments. Two types of filamentous components, short vertical projections from the postsynaptic membrane and thin filaments protruding from these projections, comprised the basic structure of the postsynaptic specialization, but their sizes and distribution differed at each chemical type of terminal. For instance, the postsynaptic specialization at the glycine terminal was distinguished by numerous thin filaments which curved sideways to run parallel to the plasmalemma. Thus, freeze‐substitution gives new information about structural differences between chemically different types of synapses, which may reflect differences in their transmitter storage, release, and reception. In addition, the AVCN preparation is of general interest in making cell bodies in the mammalian central nervous system available to the various structural and analytical techniques which depend on direct, rapid freezing.
Distribution of nuclear pores and chromatin organization in neurons and glial cells of the rat cerebellar cortex
Authors: Garcia‐Segura L. M. , Lafarga M. , Berciano M. T. , Hernandez P. , Andres M. A.
Published: January 2005

Nuclear pores were assessed on freeze‐fracture replicas from different neuronal and glial cell types of the rat cerebellar cortex. Nuclear diameter and perimeter were measured on semithin sections, and nuclear surface area and volume were calculated from these data. The proportion of inner nuclear membrane in apposition to condensed chromatin was measured on thin sections. The values of nuclear pore numerical density (number/μm2) were as follows (mean ± S.D.): Purkinje cells, 22 ± 3; Golgi cells 17 ± 3; granule cells, 6 ± 4; stellate and basket cells, 6 ± 1; protoplasmic astrocytes, 11 ± 1; Bergmann glia, 10 ± 1; oligodendrocytes, 6 ± 1. The total number of nuclear pores per nucleus varied from 18,451 ± 2,336 (Purkinje cells) to 621 ± 394 (granule cells) among neurons, and from 1,782 ± 162 (protoplasmic astrocytes) to 402 ± 67 (oligodendrocytes) among glial cells. The number of nuclear pores per unit nuclear volume (number/μm3), a parameter related to nucleocytoplasmic transport capacity, varied from 15 ± 2 in Purkinje cells to 6 ± 4 in granule cells. The proportion of nuclear membrane free of condensed chromatin was significantly (P < 0.01) correlated to pore numerical density and total number of pores per nucleus. Some nuclear pores were associated in clusters of two or more pores. The amount of pore clustering was measured by counting the proportion of pores associated in clusters. This proportion varied among the different cell types from 82% in Purkinje cells to 44% in stellate and basket cells. The amount of pore clustering showed a positive linear correlation to pore numerical density and pore number per nucleus. However, the proportion of pores in clusters was not significantly correlated with the amount of condensed chromatin applied against the inner nuclear membrane.
Glutamic‐acid‐decarboxylase‐ and parvalbumin‐like‐immunoreactive structures in the olfactory bulb of the human adult
Authors: Ohm T. G. , Müller H. , Ulfig N. , Braak E.
Published: January 2005

This study examines the distribution and morphological characteristics of glutamic‐acid‐decarboxylase‐like (GAD)‐ and parvalbumin‐like (PA)‐immunoreactive structures in the olfactory bulb of the human adult.

GAD‐immunoreactive somata occurred in the glomerular layer, the external granule cell layer, the more superficial portion of the external plexiform layer, and the internal granule cell layer. The cells were small‐ to mediumsized. Demonstration of lipofuscin pigment revealed the presence of unpigmented as well as pigmented neurons, thus suggesting the existence of two subpopulations of GAD‐positive neurons. GAD‐immunoreactive puncta and/or fibers were mainly seen in the periglomerular region and the internal granule cell layer. All other layers of the bulb, as well as the intrabulbar portion of the anterior olfactory nucleus, displayed considerably less of these puncta and/or fibers. The olfactory nerve layer remained practically clear of immunoreactive material.

PA‐immunoreactive somata occurred in the glomerular layer and both the external and internal granule cell layer. Only a small number of immunoreactive nerve cells were encountered within the white matter or the olfactory tract. Most PA‐positive neurons displayed characteristics of short axon cells whereas a few others resembled van Gehuchten cells. All of the PA‐immunoreactive neurons were devoid of lipofuscin pigment. Immunoreactive puncta and fibers were present in all layers though predominating in the periglomerular region, the olfactory nerve layer, and the internal granule cell layer. The intrabulbar portions of the anterior olfactory nucleus did not show any immunoreactive structures.
Tectal connectivity in the frog Rana pipiens: Tectotegmental projections and a general analysis of topographic organization
Authors: Masino Tom , Grobstein Paul
Published: January 2005

Recent studies of visually elicited orienting in the frog Rana pipiens suggest that tectofugal signals important in this behavior relay in the midbrain tegmentum before descending to the spinal cord. They also suggest that the high degree of topographic organization displayed by the retinotectal projection may be less characteristic of other tectal afferent and efferent pathways. To explore these possibilities, we have studied patterns of retrograde and anterograde labelling following multiple and single injections of horseradish peroxidase into the tectum.

We have found that the midbrain tegmentum is major terminal zone for tectal efferent projections. Our material also provided a description of the boundaries of other structures which project to and receive input from the tectum. With this background, we studied topographic organization by analyzing for each structure the distribution of labelling following multiple injections, and comparing it with the label distribution following single injections at tectal loci with known visual field input. Multiple injections produced patchy anterograde and retrograde labelling in the nucleus isthmi, with the number of patches corresponding to the number of tectal sites injected. Single injections produced labelling in restricted regions of the nucleus isthmi, the location of which varied systematically with the location of the tectal injection site. In all other structures studied, labelling was more evenly distributed following multiple injections. In none of these structures could we detect systematic variations in the location of labelling associated with variations in the location of single tectal injection sites, and the labelling following single injections was frequently coextensive with that following multiple injections. We also found no evidence that there exist structures which project to or receive input from particular tectal regions and not others.

We conclude that there exist adequate neuroanatomical substrates for a tectotegmentospinal pathway believed to be important for visually elicited orienting in the frog. We also conclude that a high degree of topographic organization is more the exception than the rule in considering tectal connections generally in the frog. Topographic organization was readily apparent in connections related to the nucleus isthmi but not in connections related to any other nonretinal structure.
Birthdates of the growth hormone releasing factor cells of the rat hypothalamus: An autoradiographic study of immunocytochemically identified neurons
Authors: Rodier Patricia M. , Kates Barbara , White Wendy A. , Phelps Carol J.
Published: January 2005

Growth hormone releasing factor (GRF) neurons in the arcuate nucleus of the hypothalamus and somatostatin (SRIF) neurons in the anterior periventricular region of the hypothalamus act to control the release of growth hormone from the anterior pituitary. To investigate the possibility that the growth‐controlling functions of these cells might be compromised by injuries to the developing brain, it is important to know the details of the production and differentiation of these small, specialized cell groups. The overall pattern of cell production in the hypothalamus is known from autoradiographic studies with general nuclear stains, but no data are available on the birthdates (times of final mitoses) of GRF‐producing cells. The present study was undertaken to determine when the GRF cells form. Counts of immunocytochemically identified GRF cells labeled on given days were taken from serial coronal sections through the hypothalamus of adult rats labeled on the 10th‐17th days of gestation (day of finding a vaginal plug = day 1). As has been shown for the hypothalamus in general, the GRF cells showed a gradient of production from anterior to posterior. The peak of anterior cell proliferation was on day 13, middle cells on day 14, and posterior cells on day 15. These dates are 1 or 2 days earlier than those of GRF‐negative cells in the same regions. No lateral to medial gradient of formation was seen in GRF cells. Rather, the laterally placed cells along the base of the brain and those surrounding the ventromedial nucleus formed simultaneously with the GRF cells of the arcuate nucleus. The birthdating results presented here are in agreement with the results of studies of teratogens which suggest that rat postnatal growth is reduced most severely by exposure to neurotoxic agents on days 12 or 13 of gestation. On the basis of data for the whole hypothalamus, such treatments would appear to be too early to interfere with cell production for the arcuate nucleus, but the timing fits the period of vulnerability as defined by the birthdates determined in the present study for the subpopulation of cells destined to produce GRF.
GABA‐ergic neurons in the crayfish nervous system: An immunocytochemical census of the segmental ganglia and stomatogastric system
Authors: Mulloney Brian , Hall Wendy M.
Published: January 2005

We used an antiserum directed against γ‐aminobutyric acid (GABA) fixed with glutaraldehyde (Hoskins et al., Cell Tissue Res. 244:243‐252, '86) to label neurons with GABA‐like immunoreactivity (GLI) in wholemounts of the stomatogastric ganglion and each segmental ganglion of crayfish, except the brain. Each abdominal ganglion had an average of 63 labeled neurons, or 10% of all their neurons. Each peripheral nerve of each abdominal ganglion except the last contained labeled axons. Within each segment, the first peripheral nerve, N1, had five axons; the second peripheral nerve, N2, had at most four; and the third peripheral nerve, N3, had two. In the last ganglion, N2 had one labeled axon, N3 had two and N6 had two; the other nerves contained no labeled axons. A tabulation of the identified inhibitory neurons in the abdominal ganglia revealed that 40% of these GABA‐ergic neurons have been identified. The subesophageal ganglion had many labeled neurons in clusters that formed a repeating pattern; it also had labeled neurons near its dorsal midline. The thoracic ganglia contained more labeled neurons than did the abdominals, but their patterns of labeling were similar. The commissural ganglia contained three clusters of labeled neurons and sent labeled axons to the esophageal ganglion. The esophageal ganglion contained four labeled neurons and many labeled axons. The stomatogastric ganglion contained labeled axon terminals but no labeled neurons.
Organization and postnatal development of zebrin II antigenic compartmentation in the cerebellar vermis of the grey opossum, monodelphis domestica
Authors: Doré Louise , Jacobson Carol D. , Hawkes Richard
Published: January 2005

The mammalian cerebellar cortex consists of a number of parasagittal Purkinje cell compartments that can be demonstrated cytochemically. The afferent inputs to the cerebellum are also compartmentalized, and a complex but reproducible relationship exists between the afferents and the intrinsic maps. Developmental studies in the rat have shown that many of the main features of compartmentation are already established at birth, and are therefore not easily manipulated experimentally. The compartmentation antigen zebrin II is expressed selectively by Purkinje cell subsets in a range of species, including fish and primates. In this study, zebrin II immunoreactivity has been studied in the grey opossum, Monodelphis domestica, in order to develop a marsupial model of compartment formation in which the early developmental events are more readily accessible. A monoclonal antibody to zebrin II from the weakly electric fish Apteronotus recognizes a 36 kD polypeptide in homogenates of Monodelphis cerebellum that appears to be identical to the antigen in the rat.

Immunocytochemistry reveals that zebrin II in adult Monodelphis is confined exclusively to the cerebellum, where it is expressed by a subset of Purkinje cells. All regions of the cell, except the nucleus, are stained. The zebrin II+ Purkinje cells are arranged in a set of parasagittal compartments interposed by similar zebrin II− compartments. In each hemicerebellum there is one zebrin II+ band abutting the midline (P1+), and two others laterally in the vermis (P2+, P3+). A fourth zebrin II+ compartment straddles the paravermian region (P4+). Three other compartments have been identified in the hemisphere (P5+, P6+, P7+). This arrangement is very similar to that found in the rat. During postnatal development, zebrin II is first expressed between P14 and P21 in Purkinje cells of the posterior lobe vermis, and spreads throughout the cerebellar cortex by P28. As in rat, there is a stage at which all Purkinje cells are zebrin II+, including those destined to be zebrin II− in the adult. The mature pattern of expression emerges after P35 as immunoreactivity gradually disappears from the cells destined to become zebrin II−. The adult appearance is attained only after P56. The developmental timetable is therefore similar to that in rat, but is rather more protracted. Monodelphis should prove to be a valuable experimental model in which to study the early events leading to the formation of cerebellar compartments.
Disposition of the slab‐like modules formed by axon branches originating from single CA1 pyramidal neurons in the rat hippocampus
Authors: Tamamaki Nobuaki , Nojyo Yoshiaki
Published: January 2005

The hippocampus is thought to be an area where the neuronal circuits for short‐term memory or the cognitive map may reside. In order to advance theoretical studies and neuronal model simulations of such circuits, the projection of the CA1 pyramidal neurons in the rat dorsal hippocampus, especially in the subiculum, was studied by means of intracellular and extracellular HRP injection. The CA1 pyramidal neurons project principally to the subiculum where each forms a slab‐like axonal field 2 mm long along the septotemporal axis, which may be regarded as a module for columnar organization, at a specific rostrocaudal level of the subiculum. The modules of the CA1a pyramidal neurons are disposed in the rostral part of the subiculum, those of the CA1c pyramidal neurons in the caudal part, and those of the CA1b pyramidal neurons in the middle part of the subiculum. The CA1 pyramidal neurons also participate in the construction of the lamellar organization in the hippocampus in that their axon branches run rostrocaudally following the stream of the alvear fibers. The CA1 pyramidal neurons in the dorsal rat hippocampus transfer the topographic map from field CA1 to the subiculum with reversed order in the lamellar direction. The topographical relationship is composed of partially shifted, overlapping slab‐like modules. As a result, information conveyed through a lamella will diverge into the subiculum approximately 2 mm wide, and information through a group of lamellae 2 mm wide will converge upon single subicular neurons.
Ultrastructural three‐dimensional reconstruction of group III and group IV sensory nerve endings (“free nerve endings”) in the knee joint capsule of the cat: Evidenence for multiple receptive sites
Authors: Heppelmann B. , Messlinger K. , Neiss W. F. , Schmidt R. F.
Published: January 2005

The noncorpuscular endings (“free nerve endings”) of thinly myelinated group III and nonmyelinated group IV afferent nerve fibers have been examined in the knee joint capsule of sympathectomized cats by transmission electron microscopy and three‐dimensional reconstruction of series of semi‐ and ultrathin sections. The sensory ending is the most distal part of a group III or IV nerve fiber that consists only of the sensory axon and associated Schwann cells but lacks a myelin sheath and is not surrounded by perineurium. The sensory axon divides into several branches and forms a terminal tree. The branches run either as single fibers or within small Remak bundles in parallel to sensory axons of other endings; they spread along vessel walls and also extend into dense connective tissue. Each sensory axon consists of a series of spindle‐shaped thick segments “beads” connected by waist‐like thin segments. Thus all axons of sensory endings have a string‐of‐beads appearance, which resembles that of efferent sympathetic nerve fibers. The beads of the sensory axon and the end bulb at its tip show the same ultrastructural features which are characteristic of receptive sites: an accumulation of mitochondria and glycogen particles and various vesicles in the axoplasm and “bare” areas of axolemma that are not covered by Schwann cell processes. Group III and group IV sensory endings differ in the length of their branches up to 200 μm in group III vs. more than 300 μm in group IV, number of beads per 100 μm axon length about seven vs. nine or ten, mean diameter of axons 0.9‐1.5 μm vs. 0.3‐0.6 μm, and the presence of a neurofilament core consisting of bundles of parallel microfilaments only in group III. In conclusion, we propose that the sensory part of noncorpuscular “free nerve endings” is formed by the entire terminal tree of group III or group IV nerve fibers and that the beads in the course of the sensory axon represent multiple receptive sites.
Co‐localization of FLRF‐ and vasopressin‐like immunoreactivity in a single pair of sexually dimorphic neurones in the nervous system of the locust
Authors: Evans Peter D. , Cournil Isabelle
Published: January 2005

The distribution of Phe‐Leu‐Arg‐Phe (FLRF)‐like immunoreactivity is described in the brain and in the ganglia of the ventral nerve cord of the locust Schistocerca gregaria. A single homologous pair of immunoreactive cell bodies occurs ventrally and medially in the suboesophageal ganglion. Each cell sends a process dorsally which bifurcates into anteriorly and posteriorly running neurites. The single anterior neurite passes along the circumoesophageal connectives to the brain where it ascends in a posterior running tract, giving off branches to innervate the tritocerebral neuropile and ending in an extensive network of highly varicose immunoreactive processes in the protocerebral neuropile. No processes are seen in the optic lobes or associated with the structured neuropiles of the mushroom bodies. The single posterior neurite from each cell passes into the suboesophageal‐prothoracic connectives. It runs in the lateral dorsal tract of each ganglion in the ventral nerve cord as a highly varicose process and in each ganglion gives rise to an ipsilateral network of varicose processes in the dorsal and lateral neuropiles. In the seventh and terminal abdominal ganglia the innervation pattern exhibits sexual dimorphism. Vasopressin‐like immunoreactivity is co‐localized in the same pair of suboesophageal neurones and their processes.

A similar pair of ventral median neurones stains with both antibodies in the suboesophageal ganglion of another species of locust, Locusta migratoria. Although the basic distribution pattern of immunoreactive processes is similar in both species there are also marked species differences in the pattern.
Functional organization of ascending and descending connections of the cochlear nucleus of horseshoe bats
Authors: Vater Marianne , Feng Albert S.
Published: January 2005

The ascending projections of the cochlear nucleus (CN) and the sources of descending inputs to the CN were investigated in horseshoe bats (Rhinolophus rouxi) by tracing the anterograde and retrograde transport of horseradish peroxidase (HRP or WGA‐HRP) injected into the CN. The tracer was iontophoretically deposited into physiologically characterized regions of the cochlear nucleus (Feng and Vater, '85). We report the course and termination of pathways arising from the anteroventral (AVCN), posteroventral (PVCN), and dorsal (DCN) cochlear nucleus. The projection fields within the auditory brainstem centers (superior olivary complex [SOC]; lateral lemniscus complex [LLC]; and inferior colliculus [IC]) and their tonotopic organization according to the frequency representations at the injection sites are described. While the projection pattern is generally in accordance with other mammals, several species‐characteristic features are noted: (i) the lateral superior olive (LSO) receives tonotopically organized input from both the AVCN and PVCN; (ii) the CN‐projections to medial nuclear groups of the SOC located between the LSO and the medial nuclear of the trapezoid body do not support previously suggested homologies; (iii) the ventral nucleus of the LLC can be subdivided into two divisions with distinct input patterns from the AVCN and PVCN, respectively.
Topography in the phrenic motoneuron nucleus demonstrated by retrograde multiple‐labelling techniques
Authors: Gordon D. C. , Richmond F. J. R.
Published: January 2005

A combination of retrograde tracing methods was employed to distinguish populations of motoneurons supplying different motor unit territories in the feline diaphragm. The compatibility of the tracers—horseradish peroxidase, fast or true blue, diamidino yellow, and fluorogold—was first assessed by applying the different tracers concurrently to separate cut branches of hindlimb and neck muscle nerves. On the basis of these initial observations fast blue, fluorogold, and horseradish peroxidase were chosen to compare the distribution of motoneurons whose axons ran in different primary branches of the phrenic nerve. Motoneurons with different target territories were extensively intermixed throughout most of the phrenic motor nucleus. However, motoneurons innervating the sternal and medial costal part of the diaphragm were distributed more densely in the rostral part of the phrenic motor pool, whereas motoneurons serving the lateral costal part were concentrated more caudally. Crural motoneurons were intermingled with costal motoneurons in the middle and caudal portions of the nucleus. Motoneurons within the phrenic nucleus are distributed in clusters. Such clusters commonly contained motoneurons labelled from two or more primary branches. Thus, the highly ordered topography of muscle units in the diaphragm is not mirrored by the intraspinal distribution of phrenic motoneurons.
Axo‐axonic chandelier cells in the rat fascia dentata: Golgi‐electron microscopy and immunocytochemical studies
Authors: Soriano Eduardo , Nitsch Robert , Frotscher Michael
Published: January 2005

Synaptic transmission can be blocked very efficiently by inhibitory synapses on axon initial segments. Inhibitory chandelier cells forming synapses on the axon initial segment of pyramidal neurons have been found in the neocortex and hippocampus proper. Here we describe an axo‐axonic local circuit neuron in the rat fascia dentata that establishes synaptic contacts with axon inital segments of numerous dentate granule cells. Examination of a large number of Golgi‐impregnated nongranule cells in the fascia dentata of rats revealed a group of neurons with characteristics of chandelier cells. Thus these cells exhibited an extensive axonal plexus within the granular layer that characteristically formed vertical aggregations of axonal varicosities. The cell bodies of these neurons were located in the inner molecular layer or in the outer part of the granular layer. Their dendrites invaded the molecular layer, suggesting an afferent innervation similar to that of the granule cells. Well impregnated putative axo‐axonic cells were gold‐toned for an electron microscopic analysis. The cell bodies and dendrites of these neurons exhibited characteristic ultrastructural features of nongranule cells, i.e., large amounts of perinuclear cytoplasm, infoldings of the nuclear membrane, and a large number of synaptic contacts on the perikaryon and on the smooth dendritic shafts. The axon originating from the cell body or from a proximal dendrite gave rise to numerous vesicle‐filled varicosities that almost exclusively formed symmetric synaptic contacts with axon initial segments. A semiquantitative study of five axonal complexes demonstrated that 92.3% of identified postsynaptic elements were initial segments of granule cell axons. Immunostaining with antibodies against glutamate decarboxylase (GAD) and parvalbumin (PARV) revealed a subpopulation of neurons that very much resembled the Golgiimpregnated axo‐axonic cells with regard to cell body location, dendritic arborization, and fine structural characteristics of perikarya and dendrites. GAD and PARV were found to be coexistent in these cells. Moreover, we found GAD‐ and PARV‐immunoreactive terminals in symmetric synaptic contact with axon initial segments of granule cells. The present study has shown a hitherto unknown axo‐axonic cell in the rat fascia dentata. On the basis of our immunocytochemical findings, we hypothesize that this cell exerts a strong inhibitory effect on dentate granule cells. This way, signal transmission from the fascia dentata to the hippocampus proper within the “trisynaptic pathway” can efficiently be controlled by a group of highly specialized neurons.
Implantation of cultured sensory neurons and schwann cells into lesioned neonatal rat spinal cord. II. Implant characteristics and examination of corticospinal tract growth
Authors: Kuhlengel Keith R. , Bunge Mary Bartlett , Bunge Richard P. , Burton H.
Published: January 2005

The purpose of this study was to test the effectiveness of implants derived from peripheral neural tissue to serve as bridges following interruption of the developing corticospinal tract (CST). Implants prepared from purified populations of cultured dorsal root ganglion neurons (DRGNs) and Schwann cells (SCs) (Kuhlengel et al., J. Comp Neurol. 293:63‐73, 1990) were placed into thoracolumbar regions of neonatal rat spinal cord from which a 2‐mm length of dorsal columns had been removed by suction. These cords were examined by a number of techniques 10 days to 6 months later.

The implants, recognizable by their DRGN content, filled the vacated dorsal columns and survived the longest periods examined. The most effective method to maintain implant position was dorsal placement of collagen‐coated Nitex filter. Implants were inserted either at the time of lesioning of 5 days later. The implant survival rate was better (72% vs. 50%) and meningeal scarring was less with immediate implantation, but delayed implantation resulted in better implant‐cord fusion and the implant better filled the lesion cavity. DRGN/SC implants became well vascularized without leptomeningeal cells; this may explain why implant survival was not improved with leptomeningeal cell addition. Particularly well‐differentiated implants (full extracellular matrix production and myelination) did not fuse as well with cord as did those less well differentiated. The addition of nerve growth factor to the Nitex filter collagen coating led to improved survival of DRGNs in implants. Electron microscopy showed that astrocytes populated the implant‐cord junction region and migrated into implants. Typical SCs related to nonmyelinated and myelinated axons were present in implants. Close proximity of astrocytes and central myelin to SCs and peripheral myelin demonstrated good implant integration with cord. Clusters of SCs, astrocytes, and axons, all enclosed within a common basal lamina, were observed in implants. Immunostaining for GFAP and laminin confirmed our microscopy findings that SCs did not migrate from implant into host but that astrocytes left host tissue to enter implants.

Neuroanatomical tracing of CST neurons with HRP‐WGA showed that labeled fibers were not present in the implant but were fasciculated just beneath in gray matter. These fibers remained clustered in gray matter under‐neath the ventral dorsal columns caudal to the lesion. In lesioned but not implanted rats, labeled fibers were only diffusely distributed in gray matter. Delayed implantation led to more variation in fasciculation compared with immediate implantation. In conclusion. DRGN/SC implants did not serve as tissue bridges but appeared to influence adjacent cord parenchyma to permit CST fiber fasciculation that persisted beyond the implant.