bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of GAT‐1, a high‐affinity gamma‐aminobutyric acid plasma membrane transporter in the rat retina
Authors: Brecha Nicholas C. , Weigmann Christine
Published: January 2005

Gamma‐aminobutyric acid (GABA) plasma membrane transporters influence synaptic transmission by high‐affinity, Na+‐dependent transport processes. The cDNA clone, GAT‐1, encodes a high‐affinity Na+‐ and Cl−‐dependent GABA plasma membrane transporter, which has kinetic and pharmacological properties similar to those of high‐affinity GABA uptake systems associated with neurons. The present study evaluates the distribution and cellular localization of this putative neuronal GABA transporter by RNA blot hybridization and in situ hybridization histochemistry in the rat retina. Northern blot hybridization analysis of total retinal and cerebellar RNA extracts demonstrated a single band of hybridization at 4.2 kilobases. GABA transporter mRNA is expressed by numerous cells that are distributed to the proximal inner nuclear layer and the ganglion cell layer and by a few cells located in the inner plexiform layer. Double label studies combining the retrograde transport of the fluorescent dye Fluorogold from the superior colliculus to identify ganglion cells and in situ hybridization histochemistry demonstrated that most GAT‐1 mRNA‐containing cells in the ganglion cell layer are displaced amacrine cells, although some ganglion cells containing GAT‐1 mRNA were visualized. In freshly dissociated retinal cell preparations, the GAT‐1 RNA signal is strong in neurons and weak to moderate in specialized glial cells called Müller cells. Müller cells were identified by both their morphology and the presence of the selective Müller cell marker cellular retinaldehyde‐binding protein. Only background labeling is seen with the sense GAT‐1 RNA probe in both tissue sections and dissociated retinal cell preparations. These findings demonstrate that GAT‐1 mRNA is expressed in both the retina and brain. In the retina, this transporter is predominantly localized to amacrine, displaced amacrine and interplexiform cells, and some ganglion cells. This transporter mRNA is also expressed by Müller cells but at a lower level than by neurons. These observations indicate that GABA transport by GAT‐1 plasma membrane transporters in the retina is mediated by both neurons and glia cells. © 1994 Wiley‐Liss, Inc.
Immunocytochemical localization of L‐DOPA and dopamine in the brain of the chicken (Gallus domesticus)
Authors: Moons Lieve , van Gils Jelle , Ghijsels Els , Vandesande Frans
Published: January 2005

A light microscopic immunocytochemical study, with antisera against dihydroxyphenylalanine (L‐DOPA) and dopamine (DA), revealed the dopaergic and dopaminergic systems in the brain of the chicken (Gallus domesticus). L‐DOPA‐ and DA‐immunoreactive (ir) elements are similarly distributed throughout the entire brain. Virtually all regions of the brain contained a dense innervation by L‐DOPA‐ and DA‐immunopositive varicose fibers. The neuronal cell bodies immunoreactive for the two monoamines were confined to more restricted regions, the hypothalamus, the midbrain and the brainstem. In the hypothalamus, DA‐ and L‐DOPA‐ir neurons were subdivided into a medial periventricular and a lateral group. The medial group starts at the level of the anterior commissure, in the ventral part of the nucleus periventricularis hypothalami, and continues in a more dorsal periventricular position caudally into the dorsal tuberal hypothalamic region. Densely labeled cerebrospinal fluid contacting cells can be observed in the paraventricular organ. The lateral group consists of immunopositive neurons loosely arranged in the lateral hypothalamic area and in the nucleus mamillaris lateralis. Most of the dopaminergic cell groups, identified in the hypothalamus of mammals, could be observed in the chicken, with the exception of the tuberoinfundibular group. The majority of L‐DOPA‐and DA‐ir perikarya is, however, situated in the mesencephalic tegmentum, in the area ventralis of Tsai and in the nucleus tegmenti pedunculo‐pontinus, pars compacta, the avian homologues of, respectively, the ventral tegmental area and the substantia nigra of mammals. In the pons, dense groups of cells are found in the locus coeruleus and in the nucleus subcoeruleus ventralis and dorsalis. A few labeled cells appear in and around the nucleus olivaris superior in the most caudal part of the metencephalic tegmentum. In the medulla oblongata, L‐DOPA‐ and DA‐ir cells can be seen at the level of the nucleus of the solitary tract and in a ventrolateral complex. A comparison with tyrosine hydroxylase (TH) immunocytochemistry revealed TH‐immunopositive neurons greatly outnumbering the cells exhibiting DA and L‐DOPA immunoreactivity. These results are discussed in relation to catecholaminergic systems previously reported in avian species and in the mammalian brain. © 1994 Wiley‐Liss, Inc.
Visual system of the fossorial mole‐lemmings, Ellobius talpinus and Ellobius lutescens
Authors: Herbin M. , Repérant J. , Cooper H. M.
Published: January 2005

Ocular regression in subterranean species has been shown to be associated with a number of alterations in the retina and in retinal pathways. In order to examine the consequences of eye reduction, the visual system was studied in two species of the murine genus, Ellobius, a specialized fossorial rodent. The axial length of the eye is only 2.2 mm in E. lutescens and 2.9 mm in E. talpinus. The mean soma size of ganglion cells in Nissl‐stained flatmounts is approximately 10 μm in E. lutescens and 12 μm in E. talpinus. The soma size distribution in both species appears unimodal and falls within a range‐of 6–17 μm in diameter. The topographic distribution of ganglion cells shows a weak centroperipheral gradient, and an area centralis cannot be distinguished. The total number of neurons in the ganglion cell layer in Nissl‐stained flat mounts is 12,000 in E. lutescens and 28,500 in E. talpinus and, following injection of retrograde tracers in the superior colliculus, is, respectively, 3,600 and 20,000. Based on the axial length and maximum ganglion cell density, the calculated retinal magnification factor (20–26 μm/degree) and spatial resolution (0.4–0.9 cycles/degree) of these minute eyes are extremely reduced. Retinofugal projections, demonstrated by autoradiography and horseradish peroxidase histochemistry, are similar to those in other rodents. The superior colliculus is well developed and receives a predominantly contralateral projection. Ganglion cells projecting to the contralateral colliculus are distributed over the entire retina, while cells that project ipsilaterally are restricted to the ventrotemporal region. The dorsal lateral geniculate nucleus has clearly defined binocular and monocular segments, including a partial segregation of regions receiving ipsilateral or contralateral retinal innervation. In addition, a localized region of label is observed medial to the geniculate nucleus. The retina also sends a bilateral projection to the suprachiasmatic nucleus; the intergeniculate leaflet; the pretectum; and the medial, lateral, and dorsal terminal nuclei of the accessory optic system. Sparse retinal projections were also seen in the bed nucleus of the stria terminalis, the anterior thalamus, and the inferior colliculus. A substantial retinal projection is observed in the basal telencephalon, including the cortical amygdaloid region, the diagonal band of Broca, the olfactory tubercle, and the piriform cortex. The results suggest that the morphological constraints of reduced eye size are reflected in the retina by a generally homogeneous organization but that central visual projections are not substantially modified as in some more specialized, strictly subterranean rodents. © 1994 Wiley‐Liss, Inc.
Distribution of nitric oxide synthase‐immunoreactive interneurons in the spinal trigeminal nucleus
Authors: Dohrn C. S. , Mullett M. A. , Price R. H. , Beitz A. J.
Published: January 2005

The spinal trigeminal nucleus is involved in the transmission of orofacial sensory information. Neither the distribution of the neuromessenger, nitric oxide, within the trigeminal system nor the possible relationship of this simple gas with trigeminothalamic neurons has been carefully studied. Using immunocytochemical (against nitric oxide synthase) and histochemical (NADPH‐diaphorase staining) techniques, we have found that nitric oxide neurons and processes are more prominent in the nucleus caudalis and the dorsomedial aspect of the nucleus oralis than in other spinal trigeminal regions. To study the relationship of nitric oxide to trigeminothalamic neurons and intertrigeminal interneurons of the spinal trigeminal nucleus, spinal trigeminal neurons were retrogradely labeled with fluorogold by thalamic injections or by injections into the junction of the nucleus interpolaris and nucleus caudalis. Medullary sections were subsequently processed with NADPH‐diaphorase histochemistry. None of the diaphorase‐stained neurons in the spinal trigeminal nucleus was found to contain fluorogold; however, some diaphorase‐stained processes were found in close proximity to trigeminothalamic neurons. Following spinal trigeminal nucleus injections, many diaphorasestained neurons were found to contain fluorogold, especially in the nucleus caudalis, suggesting that nitric oxide‐containing neurons in the spinal trigeminal nucleus are intertrigeminal interneurons. Collectively, these data indicate that nitric oxide is most prominent in interneurons located in nucleus caudalis and that these interneurons give rise to processes that appose trigeminothalamic neurons, raising the possibility that they may indirectly influence orofacial nociceptive processing at the level of the spinal trigeminal nucleus via nitric oxide production. © 1994 Wiley‐Liss, Inc.
Effects of vagal afferent nerve stimulation on noxious heat‐evoked Fos‐like immunoreactivity in the rat lumbar spinal cord
Authors: Evans Angela R. , Jones Sharon L. , Blair Robert W.
Published: January 2005

Electrophysiological and behavioral studies have described modulation of nociception by vagal afferent fibers. The objectives of this study were to (1) use Fos‐like immunoreactivity as a marker for neuronal activity to examine populations of neurons in the spinal cord that are activated by a noxious heat stimulus, (2) determine whether heat‐evoked Fos‐like immunoreactivity can be modulated by vagal afferent stimulation, and (3) determine whether vagallymediated effects on heat‐evoked Fos‐like immunoreactivity can be blocked by intrathecally administered serotoninergic receptor and α‐adrenergic receptor antagonists.

Neurons demonstratiring Fos‐like immunoreactivity were located in the ipsilateral superficial and deep dorsal horn laminae extending from the caudal L3 through the rostral L6 region of the spinal cord. Stimulation of the right cervical vagus nerve attenuated significantly (42%) heat‐evoked Fos‐like immunoreactivity in the superficial laminae. The reduction in Fos‐like immunoreactivity by vagal stimulation was abolished by intrathecal administration of methysergide, a nonselective serotoninergic receptor antagonist, but not by phentolamine, a nonselective α‐adrenoceptdr antagonist. These results suggest that vagal afferent modulation of spinal nociceptive transmission is mediated, at least in part, by serotonin receptors. © 1994 Wiley‐Liss, Inc.
Compartmentation of NADPH‐diaphorase activity in the mouse cerebellar cortex
Authors: Hawkes Richard , Turner Ray W.
Published: January 2005

The mammalian cerebellum is built around an array of parasagittal bands of Purkinje cells that can be demonstrated by immunocytochemical staining for the differentiation antigen zebrin II. Climbing and Mossy fiber afferents also terminate in bands, and the afferent terminal fields and the Purkinje cell bands are aligned. The convergence of mossy and climbing fiber pathways onto the Purkinje cells, which are the sole output of the cerebellar cortex, is a characteristic feature of cerebellar circuitry. Previous studies showed that when both afferent pathways are activated synchronously there develops a long‐term depression of synaptic efficacy at the parallel fiber‐Purkinje cell synapse. Two second messenger pathways mediate long‐term depression: one involves diacylglyceroland protein kinase C, and the other involves nitric oxide that is generated by a nitric oxide synthase. We have studied the distribution of nitric oxide synthase in the adult Mouse cerebellum by using nicatinamide adenine dinucleotide phosphate (NADPH)‐diaphorase histochemistry. NADPH‐diaphorase activity is found mainly in the granule and basket cells. Within the granular layer NADPH‐diaphorase activity is expressed nonuniformly patches of granule cells and synaptic glomeruli. The patches are yseen in all lobules, are reproducible from individual to individual, and are topographically ordered with respect to the Purkinje cell compartments as revealed by using anti‐zebrin II immunocytochemistry. These data imply that nitric oxide‐dependent, long‐term depression may only involve a subset of mossy fiber/granule cell projections, and that one role for nitric oxide may be to refine cerebellar receptive fields. © 1994 Wiley‐Liss, Inc.
Development of the retinofugal projections in the embryonic and larval zebrafish (Brachydanio rerio)
Authors: Burrill John D. , Easter Stephen S.
Published: January 2005

Studies of the projection from the vertebrate retina have contributed significantly to current concepts of neural development. The zebrafish has recently become a favored system for the study of development in general and neural development in particular. Although the development of both the optic nerve and the retinotectal projection of the zebrafish has been described, the retinofugal projection in its entirety has not. This paper describes it and also addresses the issue of projectional exuberance: i. e., transient projections to targets that are not innervated in the adult.

The retinofugal projection of embryonic and larval zebrafish (32 hours to 7 days post‐fertilization) was labeled by intraocular injection of DiI (1,1′‐dioctadecyl‐3,3,3′,3′, tetramethylindocarbocyanine perchlorate) and then studied in wholemounts and sections.

The first optic axons crossed the chiasm at 32 hours post‐fertilization and projected in a straight line to reach the tectum at about 44 hours. At 48 hours, a few optic axons deviated along either the tract of the posterior commissure or the tract of the postoptic commissure. By 72 hours (about the time of hatching) optic axons arborized in ten distinct regions, termed arborization fields. At 6–7 days post‐fertilization, the same ten arborization fields (nine contralateral, one bilater) were evident. Most of the arborization fields were located in the superficial neuropil and were not associated with morphologically identifiable clusters of somata. On the basis of various landmarks, the ten arborization fields are identified as precursors of retinorecipient nuclei previously described in other adult cypriniform fishes.

The development was characterized by the nearly complete absence of any transient projections. Thus, the idea that axonal outgrowth is initially exuberant and trimmed back later is not supported by these results. © 1994 Wiley‐Liss, Inc.
Distribution of motoneurons supplying dorsal and ventral suboccipital muscles in the feline neck
Authors: Kitamura S. , Richmond F. J. R.
Published: January 2005

A combination of retrograde tracers was used to compare the relative distributions of motoneurons supplying the ventral and lateral suboccipital muscles, rectus capitis anterior (RCA), and rectus capitis lateralis (RCL), with those supplying dorsal muscles, including rectus capitis posterior muscles (RCP), complexus (CM), and the medial head of obliquus capitis superior (OCS). Three of the tracers, horseradish peroxidase, fluororuby, and fluoresceinconjugated dextran, were applied to cut nerve ends. Fast blue was applied by intramuscular injection, and fluorogold was delivered both by injection and by cut nerve exposure. Motoneurons supplying RCA and RCL were clustered on the medial wall of the ventral horn in a restricted region defined previously as the commissural nucleus. Labelled cells supplying RCL were confined to the C1 segment, but those supplying RCA were distributed from C1 to rostral C4. Motoneurons supplying RCA tended to lie more dorsomedially than those supplying RCL, but there was substantial overlap between the two populations. Motoneurons supplying dorsal muscles had a separate, more ventral distribution. RCP motoneurons were located primarily in the ventromedial nucleus, but a small proportion of cells was found in the white matter of the ventral funiculus or the gray matter surrounding the central canal. Motoneurons supplying CM and OCS were located dorsomedially to the RCP cell population. These results suggest that neck motoneurons are arranged according to a “musculotopic” pattern in which dorsal muscles have the most ventral locations, and progressively more lateral and then ventral muscles are layered dorsomedially along the medial wall of the ventral horn. © 1994 Wiley‐Liss, Inc.
Differential expression of five N‐methyl‐D‐aspartate receptor subunit mRNAs in the cerebellum of developing and adult rats
Authors: Akazawa Chihiro , Shigemoto Ryuichi , Bessho Yasumasa , Nakanishi Shigetada , Mizuno Noboru
Published: January 2005

Five N‐methyl‐D‐aspartate (NMDA) receptor subunits have been identified thus far: NR1, NR2A, NR2B, NR2C, and NR2D. Here, we have analyzed the expression patterns of mRNAs for the NMDA receptor subunits in the developing and adult rats by in situ hybridization. The developmental changes of the expression patterns were most salient in the cerebellum.

In the external granular layer, hybridization signals of mRNAs, for NR1, NR2A, NR2B, and NR2C appeared by postnatal day 3, but no NR2D mRNA was expressed at any developmental stage examined. The NR1 mRNA was expressed in all cerebellar neurons at all developmental stages examined. The signals for the NR2A mRNA appeared in Purkinje cells and granule cells during the second postnatal week. The signals for the NR2B mRNA in granule cells were seen transiently during the first 2 weeks after birth. The signals for NR2C mRNA appeared in granule cells and glial cells during the second postnatal week. The signals for NR2D mRNA appeared transiently in Purkinje cells during the first 8 postnatal days; in adult rats, these were seen in stellate and Golgi cells. In the cerebellar nuclei, mRNAs for NR1, NR2A, NR2B, and NR2D were more or less expressed on postnatal day 0, while expression signals for the NR2C mRNA were first detected in postnatal day 14. Thus, the most conspicuous changes of expression patterns were observed in the cerebellar cortex during the first 2 weeks after birth, when development and maturation of the cerebellum proceed most rapidly. © 1994 Wiley‐Liss, Inc.
Cloning and in situ hybridization analysis of estrogen receptor, progesterone and androgen receptor expression in the brain of whiptail lizards (Cnemidophorus uniparens and C. inornatus)
Authors: Young Larry J. , Lopreato Gregory F. , Horan Karen , Crews David
Published: January 2005

Gonadal steroid hormones act upon specific areas of the vertebrate brain to affect the reproductive physiology and behavior of the animal. Steroid receptors are members of a superfamily of ligand‐dependent transcription factors that mediate the effects of steroid hormones by modulating gene expression in the cells containing the receptors. The neuroanatomical distributions of steroid receptor‐containihg cells have been described for several species by using steroid autoradiography, immunocytochemistry, and more recently in situ hybridization. We have used the polymerase chain reaction to amplify and clone fragments of the estrogen receptor, progesterone receptor, and androgen receptor of whiptail lizards (genus Cnemidophorus). These clones were used to produce probes for use in in situ hybridization assays and to map the neuroanatomical distribution of all three sex steroid hormone receptors in the forebrains of unisexual (C. uniparens) and sexual (C. inornatus) species of whiptail lizards. The distribution of receptor‐expressing cells reported here is in general agreement with previous reports in other species with receptor‐containing cells concentrated in septal, amygdaloid, cortical, preoptic, and hypothalamic nuclei. © 1994 Wiley‐Liss, Inc.
Response properties of nociceptive and low‐threshold neurons in rat trigeminal pars caudalis
Authors: McHaffie John G. , Larson Michelle A. , Stein Barry E.
Published: January 2005

There is little doubt that trigeminal nociceptive neurons play a critical role in signaling the presence of harmful, or potentially harmful, orofacial stimuli. Unfortunately, there is only a limited understanding of how these neurons code such stimuli and whether this code is maintained in those structures responsible for generating overt reactions. The present series of experiments were designed to quantitatively document the response properties of nociceptive neurons in the rat trigeminal pars caudalis using the same electrical and innocuous and/or noxious mechanical and thermal stimuli employed in the characterization of nociceptive neurons with orofacial receptive fields in the rat superior colliculus. Neurons were classified as either low‐threshold mechanoreceptive, wide‐dynamic‐range, or nociceptive‐specific (type I, II) depending on their responsiveness to these stimuli. Nociceptive pars caudalis neurons (92/135, 68%) had receptive field organizations and input fibers (as indicated by latencies to electrical stimuli) quite different from those of low‐threshold neurons (43/135, 32%). Nociceptive stimulus‐response relationships for the population of wide‐dynamic‐range and nociceptive‐specific type I neurons to contact heat stimuli were positively accelerating power functions with exponents of 3.9 and 4.4, respectively. This contrasted sharply with the low‐threshold component of wide‐dynamic‐range neurons which was a negatively accelerating power function with an exponent of 0.7. All categories of nociceptive neuron also responded vigorously to cold stimuli. The thresholds of both hot and cold stimuli were often below psychophysical estimates of thermal pain, suggesting that “nociceptive” neurons process far more information than that required, to signal potentially harmful stimuli. The fundamental similarities in nociceptive properties in pars caudalis and other structures of the central nervous system suggest that there is little transformation of the information encoded at successive levels of the neuraxis. This is consistent with the idea that the functional role of nociceptive neurons is refiected more in which circuits they are integrated and less in differences in their physiological properties. © 1994 Wiley‐Liss, Inc.
Octopamine‐like immunoreactivity in the brain and subesophageal ganglion of the honeybee
Authors: Kreissl Sabine , Eichmüller Stefan , Bicker Gerd , Rapus Jürgen , Eckert Manfred
Published: January 2005

The organization of putative octopaminergic pathways in the brain and subesophageal ganglion of the honeybee was investigated with a well‐defined polyclonal antiserum against octopamine. Five prominent groups of just over 100 immunoreactive (IR) somata were found in the cerebral ganglion: Neurosecretory cells in the pars intercerebralis innervating the corpora cardiaca via NCC I, one cluster mediodorsal to the antennal lobe, one scattered on both sides of the midline of the protocerebrum, one between the lateral protocerebral lobes and the dorsal lobes, and a single soma on either side of the central body. With the exception of the pedunculi and β‐lobes of the mushroom bodies, varicose immunoreactive fibers penetrate all parts of the cerebral ganglion. Strong labelling was found in the central complex and the protocerebral bridge. Fine networks of labelled processes invade the antennal lobes, the calyces and a small part of the α‐lobes of the mushroom bodies, the protocerebrum, and all three optic ganglia.

In the subesophageal ganglion, one labelled cell body was found in the lateral soma layer of the mandibular segment. Each of the three neuromeres contains a group of six to ten somata in the ventral median parts. Most of the ventral median cells send their neurites dorsally through the midline tracts, whereas the neurites of a few cells follow the ventral cell body neurite tracts.

Octopamine‐IR was demonstrated in all neuropils that contain pathways for proboscis extension learning in honeybees. Because octopaminergic mechanisms seem to be involved in the behavioral plasticity of the proboscis extension reflex, our study provides anatomical data on the neurochemical organization of an appetitive learning paradigm. © 1994 Wiley‐Liss, Inc.
Abdominal surgery induces Fos immunoreactivity in the rat brain
Authors: Bonaz Bruno , Plourde Victor , Taché Yvette
Published: January 2005

Previous neuropharmacological studies indicate that brain peptides are involved in mediating gastric stasis induced by abdominal surgery. Central pathways activated by abdominal surgery were investigated in the rat by using Fos protein as a marker of neuronal activation. Abdominal surgery (laparotomy alone or combined with cecal manipulation) was performed under brief enflurance anesthesia (7–8 minutes), and 1 hour later rats were killed and brains processed for Fos immunoreactivity. Double labeling with Fos and arginine vasopressin, oxytocin, or tyrosine hydroxylase antibodies was also performed. Abdominal surgery induced Fos staining in the nucleus tractus solitarii, paraventricular and supraoptic nuclei of the hypothalamus, locus coeruleus, and ventrolateral medulla. After abdominal surgery, 18–25% of vasopressin and 18–33% of oxytocin‐labeled cells were found to be Fos positive in the paraventricular nucleus and 15% of activated cells in the nucleus tractus solitarii were positive for tyrosine hydroxylase immunoreactivity. Enflurane alone induced c‐fos expression in the same brain area; however, the number of Fos‐positive cells and double‐labeled cells were decreased two‐to fivefold and three‐ to eightfold, respectively, compared with the abdominal surgery groups. These data show that abdominal surgery induced activation of specific hypothalamic, pontine, and medullary neurons. These findings may have implications for the understanding of central mechanisms involved in mediating gastric ileus following abdominal surgery. © 1994 Wiley‐Liss, Inc.
Morphological analysis of external urethral and external anal sphincter motoneurones of cat
Authors: Sasaki Mitsuyoshi
Published: January 2005

A previous electrophysiological study suggested that there is a common correlation among axonal conduction velocity, input resistance, and size of motoneurones regardless of the muscle type innervated by a motoneurone and that the dendritic arborization is less developed in sphincter than in hindlimb motoneurones. To verify the previous suggestions, cell bodies, axons, and dendrites of external urethral sphincter (EUS) and external anal sphincter (EAS) motoneurones were studied after intracellular labelling with horseradish peroxidase in cats anaesthetised with pentobarbitone. All the cell bodies were located in Onuf's nucleus. The soma diameter (19.7–50.0 μm) was positively correlated with the axonal conduction velocity, and the plots of these two variables were extrapolations from similar plots obtained for hindlimb α‐motoneurones, supporting the suggestion of the preceding report. Half of motoneurones had recurrent axon collaterals, which terminated within Onuf's nucleus and the ventral border of lamina VIII. The diameter of the cell body with collaterals was significantly larger than that without collaterals. Dendrites extended in five directions: dorsal, medial, lateral, rostral, and caudal. Dorsally directed dendrites of both EUS and EAS motoneurones coursed in lamina VII toward the intermediolateral nucleus, and dendrites of EAS motoneurones further extended toward the intermediomedial nucleus. Long dendrites directed rostrally or caudally within Onuf's nucleus, more prominently in EUS motoneurones. EAS motoneurones had longer end branches and relatively larger number of end branches and summed length and surface area of a dendrite compared with EUS. Among relations, the dendritic surface area and the dendritic volume were tightly correlated with the diameter of the first‐order dendrite. The latter relation was almost identical between EUS, EAS, and hindlimb α‐ and γ‐motoneurones. The large values for the dendritic‐to‐soma surface area ratio (31 in EUS, 50 in EAS) indicated the well‐developed dendritic arborization comparable to hindlimb motoneurones. The ratio of sum Σ(daughter diameter)3/2 to the 3/2 power of the parent diameter was 0.99 in EUS and 1.08 in EAS motoneurones, indicating that the 3/2 power constraint at branching points is well satisfied, and Rall's equivalent‐cylinder model is applicable to sphincter motoneurones. © 1994 Wiley‐Liss, Inc.
Projections of individual purkinje cells of identified zones in the flocculus to the vestibular and cerebellar nuclei in the rabbit
Authors: De Zeeuw C. I. , Wylie D. R. , Digiorgi P. L. , Simpson J. I.
Published: January 2005

The rabbit flocculus can be divided into five zones (zones 1, 2, 3, 4, and C2) with the use of acetylcholinesterase histochemistry. The projections of individual Purkinje cells in these zones to the vestibular and cerebellar nuclei were studied by using biocytin as an anterograde tracer. The zones were physiologically identified in terms of the Purkinje cell complex spike modulation occurring in response to optokinetic stimulation. In zones 1 and 3 neurons respond best to rotation about a horizontal axis that is close to perpendicular to the ipsilateral anterior semicircular canal, whereas in zones 2 and 4 neurons respond best to rotation about the vertical axis. Complex spike activity in zone C2 is unresponsive to optokinetic stimulation.

Collectively, Purkinje cells of zone 1 projected to the ventral dentate nucleus, dorsal group y, and superior vestibular nucleus; Purkinje cells of zones 2 and 4 projected to the magnocellular and parvicellular parts of the medial vestibular nucleus; Purkinje cells of zone 3 projected to dorsal group y, ventral group y, and the superior vestibular nucleus; and Purkinje cells of zone C2 projected to the interposed posterior nucleus and dorsal group y. Some of the labeled Purkinje cell axons branched and innervated two nuclei. Branching axons from zone 1 either innervated both the ventral dentate nucleus and the superior vestibular nucleus or both dorsal group y and the superior vestibular nucleus. Branching axons from zones 2 and 4 innervated both the magnocellular and the parvicellular parts of the medial vestibular necleus. Branching axons from zone 3 innervated both dorsal group y and the superior vestibular nucleus, or both ventral group y and the superior vestibular nucleus. Branching axons from zone C2 innervated both the interposed posterior nucleus and dorsal group y.

Some of the target nuclei of the floccular Purkinje cell axons (e. g., dorsal group y and interposed posterior nucleus) project to the part of the inferior olive that, in turn, projects to the corresponding floccular zone, thus completing a closed pathway consisting of the inferior olive, the cerebellar cortex, and the cerebellar and vestibular nuclei. Other target nuclei (e. g., superior vestibular nucleus and medial vestibular nucleus) do not project back to the olivary subnuclei that innervate the flocculus and are part of an open olivofloccular pathway. An individual Purkinje cell thus can innervate a nucleus in the closed pathway as well as a nucleus in the open pathway. To summarize, the present study illustrates that floccular Purkinje cells located in discrete zones are part of different pathways involved in the regulation of specific components of compensatory eye movements. © 1994 Wiley‐Liss, Inc.
Thalamic connections of the primary motor cortex (M1) of owl monkeys
Authors: Stepniewska Iwona , Preuss Todd M. , Kaas Jon H.
Published: January 2005

To determine the relative contributions of transthalamic cerebellar and pallidal projections to the primary motor cortex (M1) of owl monkeys, we examined the thalamic labeling resulting from injections of fluorescent tracers and wheatgerm agglutinin/horseradish peroxidase conjugate (WGA‐HRP) into regions of M1 identified by intracortical microstimulation. Injections were placed in the major somatotopic divisions of M1 (the hindlimb, trunk, forelimb, and face representations) and in the caudal and rostral M1 subareas. In most cases, we injected several differentiable tracers into different parts of M1. Our results indicate that the strongest connections of M1 are with subdivisions of the ventral lateral thalamus (VL); other connections are mainly with intralaminar nuclei (the central lateral, paracentral, and center median nuclei) and the reticular nucleus. Most projections are reciprocal and topographically organized. M1 is strongly connected with the principal (VLp), medial (VLx), and anterior (VLa) subdivisions of the VL complex but has at most weak connections with the dorsal division (VLd). Each of the major somatotopic divisions of M1 is connected with an anteroposteriorly elongated territory within the VL complex. The connections are somatotopically organized such that the M1 hindlimb representation is connected with a band of cells in the lateral and anterior portions of the VL complex (spanning VLa and VLp), whereas the trunk, forelimb, and face representations are connected with successively more medially and posteriorly situated cell bands (spanning VLa, VLp, and VLx). There is some degree of overlap between the somatotopic territories within VL, although the absence of double‐labeled cells in cases with injections of adjacent somatotopic divisions of M1 suggests that individual thalamic neurons project to single somatotopic regions.

In addition to somatotopic differences, the connections of the caudal and rostral subdivisions of M1 differ to some extent. Caudal M1 is connected most strongly with VLp, a target of cerebellar projections, but it is also connected with VLa, which receives pallidal inputs. In complementary fashion, rostral M1 is most strongly connected with VLa, but it is also connected with VLp. VLx, a target of cerebellar projections, has significant connections with both caudal and rostral M1. These results indicate that all parts of M1 are influenced by both the cerebellum and globus pallidus in owl monkeys, as has been suggested in some recent studies of macaque monkeys. © 1994 Wiley‐Liss, Inc.
Cellular retinol‐binding protein type I is prominently and differentially expressed in the sensory epithelium of the rat cochlea and vestibular organs
Authors: Ylikoski Jukka , Pirvola Ulla , Eriksson Ulf
Published: January 2005

To understand the possible role of retinoic acid during inner ear development and cellular regeneration, we have examined the expression pattern of two intracellular retinoid‐binding proteins, the cellular retinol‐ and retinoic acid‐binding proteins of type I in the developing and mature rat inner ear. Expression of cellular retinol‐binding protein type I was seen in the supporting cells of the organ of Corti and vestibular organs as soon as the first signs of differentiation of the adjacent hair cells were seen. In the developing organ of Corti, the expression pattern followed the basal‐to‐apical coil differentiation gradient. After the 1st postnatal week, detectable expression of cellular retinol‐binding protein type I disappeared from the organ of Corti, but persisted in the supporting cells of vestibular organs throughout life. Expression of cellular retinoic acid‐binding protein type I was not found in the inner ear sensory epithelia. Cellular retinol‐binding protein type I has previously been shown to act as a substrate carrier in the synthesis of retinoic acid from its precursor, retinol. Our data suggest that retinoic acid is synthesized in the developing sensory epithelium of the cochlear and vestibular organs and that a concentration gradient formed by retinoic acid may have a role in differentiation of the cochlear sensory epithelium. Furthermore, retinoic acid may have a role in damage‐induced hair cell regeneration in the developing and mature vestibular organs as well as in the developing auditory organ. The absence of cellular retinol‐binding protein type I from the supporting cells of the mature organ of Corti may be associated with the inability of this organ to regenerate hair cells after damage. © 1994 Wiley‐Liss, Inc.
Postnatal development of the hamster cochlea. II. Growth and differentiation of stereocilia bundles
Authors: Kaltenbach James A. , Falzarano Pamela R. , Simpson Thomas H.
Published: January 2005

The postnatal development of stereocilia was studied in the Syrian golden hamster. The purpose was to describe tae morphological changes underlying the differentiation of stereocilia bundles and to define the time course of their growth in different regions of the cochlea. Differentiation of the hair bundle occurred by progressive changes in stereocilia number, dimensions, and spatial relationships. The overall transformation of the bundle is interpreted as a four‐stage process involving the initial production of stereocilia (stage I), differentiation into tall and short populations (stage II), formation of distinct ranks (stage III), and resorption of excess stereocilia (stage IV). The orientation and arrangement of stereocilia during stage II began to occur before the tectorial membrane grew over the hair cell field.

Growth in the dimensions of stereocilia occurred continuously throughout these four stages with increases in length and width occurring simultaneously. The time frame of the growth process depended both on location along the organ of Corti and on the type of hair cell. Hair bundles in the basal turn began growing and reached maturity a few days earlier than those in the apical turn. Stereocilia of outer hair cells matured earlier than those of inner hair cells. Outer hair cell stereocilia reached their adult lengths by 14 days after birth, those of inner hair cells between 16 and 18 days after birth. A kinocilium was present on almost all hair cells on the day of birth, but most were eliminated by 14 days after birth. Tip links were observed as early as 4 days after birth, and their growth appeared to be synchronous with the growth of stereocilia. The spatial gradient of stereocilia length, which increased toward the apex in the adult, was nearly the reverse of that seen at birth. The gradient for inner hair cells was associated with a gradient in the rate of stereocilia growth. The data further expand the foundation for interpreting mechanisms underlying the morphogenesis of stereocilia bundles in mammals and for understanding structure—function relationships during development. © 1994 Wiley‐Liss, Inc.
Central processing of sex pheromone, host odour, and oviposition deterrent information by interneurons in the antennal lobe of female Spodoptera littoralis (Lepidoptera: Noctuidae)
Authors: Anton Sylvia , Hansson Bill S.
Published: January 2005

Physiological and anatomical characteristics of antennal lobe interneurons in female Spodoptera littoralis (Boisd.) were investigated using intracellular recording and staining techniques. Responses of local interneurons and projection neurons to female sex pheromone components, host plant odours, and behaviourally active oviposition deterrents were recorded. We found local interneurons and projection neurons that responded specifically to only one or two of the tested odours, but we also found less specific cells, and neurons that responded to most of the tested odourants. These findings show that there are not only specific olfactory pathways in female moths up to the protocerebral level, but also that integration can begin in the antennal lobe. No correlation was found between the degree of specificity of either local interneurons or projection neurons and their respective morphological characteristics. Specialized and unspecialized local interneurons arborized throughout the antennal lobe. Specialized and unspecialized projection neurons had uniglomerular arborizations in the antennal lobe and sent their axons to the calyces of the mushroom body, and to the lateral horn of the protocerebrum. One specific projection neuron had multiglomerular arborizations and projected only to the lateral horn of the protocerebrum. Projection neurons arborizing in the glomeruli closest to the entrance of the antennal nerve always responded to pheromone components. No other correlations were found between the arborization pattern of projection neurons in the antennal lobe or in the protocerebrum and their response characteristics. The sensitivity of local interneurons and projection neurons was in the same range as that of receptor neurons in olfactory sensilla on the antennae, suggesting a much lower convergence in the central nervous system in females than in the pheromone‐processing pathway in males. © 1994 Wiley‐Liss, Inc.
Acetylcholinesterase activity in neurons of crayfish abdominal ganglia
Authors: Braun Götz , Mulloney Brian
Published: January 2005

Acetylcholine is known to be a neurotransmitter in crustacean central nervous systems, but the numbers and distribution of cholinergic neurons in the segmental ganglia have not been described. To begin a census of cholinergic neurons in these ganglia, we used a histochemical assay for acetylcholinesterase to map neurons that contained this enzyme in the six abdominal ganglia of crayfish.

In each abdominal ganglion, about 47 cell bodies were stained. The distributions of these stained cells in individual ganglia were similar, and the numbers were not significantly different. None of these stained cell bodies could be identified from their structures or locations as previously identified motor neurons or sensory neurons with central cell bodies. The process of one unpaired midline neuron that occurred only in the first three abdominal ganglia divided to send a pair of axons anteriorly into both halves of the connective.

The central projections of afferent axons from many peripheral sensory neurons stained clearly as they entered each ganglion. Terminals of these axons were heavily stained in the horseshoe neuropil and the lateral neuropils.

We labeled both γ‐aminobutyric acid (GABA) and acetylcholinesterase in individual ganglia. Only a few neurons in each ganglion were double‐labeled. The unpaired midline neurons in the three anterior ganglia that stained for acetylcholinesterase did not show GABA‐like immunoreactivity, but cells with similar shapes did label with the GABA antiserum.

Acetylcholinesterase is not a definitive marker of cholinergic neurons, but its presence is often associated with the cholinergic phenotype. These stained cells should be considered as putative cholinergic neurons. © 1994 Wiley‐Liss, Inc.
Distribution of thyrotropin‐releasing hormone (TRH)‐containing cells and fibers in the human hypothalamus
Authors: Fliers Eric , Noppen Nicolette W. A. M. , Wiersinga Wilmar M. , Visser Theo J. , Swaab Dick F.
Published: January 2005

In the present study, we describe for the first time the distribution of thyrotropin‐releasing hormone (TRH)‐containing cells and fibers in the human hypothalamus using brain material obtained with a short postmortem delay. Following fixation in paraformaldehyde, glutaraldehyde and picric acid, excellent staining was obtained with two different TRH antisera. Many TRH‐containing neurons were present in the paraventricular nucleus (PVN), especially in the dorsocaudal part of this nucleus. They were mostly parvicellular, but a few magnocellular TRH‐positive neurons were observed as well. The PVN also contained a dense network of TRH fibers. The supraoptic nucleus (SON) did not show any TRH immunoreactivity, excluding the possibility of cross‐reactivity of the antiserum with neurohypophysial hormones or their precursors. In addition, TRH cells were found in the suprachiasmatic nucleus (SCN), which is the circadian clock of the brain, in the sexually dimorphic nucleus (SDN) and dorsomedially of the SON. We observed small numbers of TRH cells throughout the hypothalamic gray in all subjects studied.

A high density of TRH‐containing fibers was seen not only in the median eminence but also in other hypothalamic areas, e.g., in the ventromedial nucleus (VM) and in the perifornical area. The results generally agree with earlier data in the rat, with the exception of the absence of TRH cells in the SON. The large number of sites of TRH‐containing fiber terminations on neurons suggests important physiological functions of this neuropeptide as a neurotransmitter or neuromodulator in the human brain in addition to its role as a neurohormone in pituitary secretion of thyroid‐stimulating hormone (TSH).
Embryonic development of the stomatogastric nervous system in Drosophila
Authors: Hartenstein Volker , Tepass Ulrich , Gruszynski‐Defeo Eileen
Published: January 2005

Using several cell‐specific markers, the pattern of proliferation, morphogenesis, and neuronal differentiation of the Drosophila larval stomatogastric nervous system (SNS) was analyzed. In the late embryo, four SNS ganglia (frontal ganglion, hypocerebral ganglion, paraesophageal ganglion, ventricular ganglion) can be distinguished. In the early embryo, the precursor cells of the SNS (SNSPs), being an integral part of the anlage of the esophagus, undergo four synchronous rounds of division. Subsequently, SNSPs segregate from the esophageal epithelium in a complex and stereotyped pattern. The majority of SNSPs invaginate and transiently form three (rostal, intermediate, caudal) pouches that, after separating from the esophagus, become epithelial vesicles. At later stages, these SNSPs gradually lose their epithelial phenotype. Starting at the anterior‐dorsal tip of each vesicle, SNSPs dissociate from one another and migrate to the various locations where they differentiate as neurons. Cells of the rostral and intermediate vesicle contribute to the frontal ganglion; the hypocerebral ganglion develops from the intermediate vesicle, the paraesophageal ganglion from the rostral vesicle, and the ventricular ganglion from the caudal vesicle. In addition to the invaginating SNSPs, several distinct groups of SNSPs delaminate as individual cells from the esophageal epithelium. Three clusters of SNSPs delaminate from a region anterior to the rostral pouch; a single SNSP delaminates from the tip of each pouch. All delaminates from the tip of each pouch. All delaminating SNSPs contribute to the frontal ganglion. A significant number of SNSPs undergo cell death. In the late embryo, the stomatogastric ganglia are interconnected by the recurrent nerve and esophageal nerves. The frontal ganglion projects to the brain via the frotal connectives. Both recurrent nerve and frontal connectives are pioneered by small subpopulations of early differentiating stomatogastric neurons that most likely derive from among the dSNSPs and iSNSPs.