bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of the retinas and optic nerves of achiasmatic belgian sheepdogs
Authors: Hogan Dale , Williams Robert W. 
Published: January 2005

AbstractAn autosomal recessive mutation carried in a family of black Belgian sheepdogs eliminates the optic chiasm—all retinal ganglion cell axons extend directly into the ipsilateral optic tract. One key issue we are trying to resolve is whether the retina or the chiasm is the principal site of mutant gene action. In this study, we have examined retinas of mutants to discover any associated changes in retinal structure.Retinas of mutant animals are relatively normal. Inner and outer nuclear layers are qualitatively indistinguishable from those of normal dogs. The principal difference is that the area centralis of mutants is smaller and has a lower peak ganglion cell density than that of normal dogs (8,100 vs. 10,500/mm2, P < 0.05). This mutant phenotype is similar to that seen in retinas of Siamese cats and albino ferrets. Beyond area centralis, the central‐to‐peripheral gradient in ganglion cell density is normal in mutants. The size of the optic nerves, density of axons, and total number of axons do not differ between mutant and normal dogs.One of three mutant dogs had a small abnormal optic chiasm. Retrograde labeling of ganglion cells demonstrated that the residual crossed projection originated from cells in a widespread region in nasal retina and not solely from the peripheral nasal region, as might be expected of an anti‐albino.Although our analysis does not rule out the retina as a site of mutant gene action, the modest differences between mutant and normal retinas suggest that the mutation either acts outside the retina or exerts a highly specific effect on ganglion cell trajectories alone. © 1995 Wiley‐Liss, Inc.
Organization of the colliculo‐suprageniculate pathway in the cat: A wheat germ agglutinin‐horseradish peroxidase study
Authors: Katoh Yoshimitsu Y. , Benedek György 
Published: January 2005

AbstractA wheat germ‐agglutinated horseradish peroxidase (WGA‐HRP) tracing technique was used to label the cell bodies of neurons in the superior colliculus that send projections into the visually sensitive region of the suprageniculate nucleus (Sg) in the feline thalamus. After determination of the position of the Sg by detecting characteristic single‐unit responses to moving visual stimuli, WGA‐HRP was injected into the Sg in five pentobarbital‐anesthetized cats. The animals were than sacrificed, and serial frozen sections of the midbrain were processed for the demonstration of peroxidase activity.A total of 2,736 WGA‐HRP‐stained neurons were located within the ipsilateral superior colliculus (SC), and a few labeled cells were consistently found bilaterally in the external nuclei of the inferior colliculus. In each cat, a small but significant fraction of the labeled cells were encountered contralateral to the injection.Medial SC neurons tended to project to the posterior Sg, and lateral SC neurons tended to project to more rostral Sg. However, labeled cells were distributed homogeneously along the rostrocaudal extent of the SC, indicating the absence of a well defined topographic relationship. Nor was the Sg injection site location related to the laminar distribution of SC projection neurons. In all cases, the majority of the labeled cells were found in layer IV (49.0%), with fewer cells in layers III (17.5%), layer V (20.0%), and layer VI (11.8%). No labeled cells were located in layer I, although a few were located in the deep part of layer II.Five types of SC projection cells were distinguished morphologically. Of the 258 labeled cells that could be characterized, 25% were stellate cells, 25% vertical cells, 20% granular cells, 17% triangular cells, and 12% horizontal cells. The average diameter of 226 cells ranged between 8 and 47 μm. We conclude that a mixed population of SC cells projects to the Sg; the morphological heterogeneity and the distribution of these cells suggests that several functionally different pathways may be involved in the colliculothalamic pathway and in the processing of visual input in the SC. © 1995 Wiley‐Liss, Inc.
Expression of FGF‐2 and FGF receptor type 1 in the adult rat brainstem: Effect of colchicine
Authors: Grothe Claudia , Janet Thierry 
Published: January 2005

AbstractIn the adult rat brainstem, neuronal subpopulations of several motor and sensory nuclei display basic fibroblast growth factor (bFGF or FGF‐2) immunoreactivity (IR; Grothe et al. J. Comp. Neurol. 305:328–336). In the present study we demonstrate that FGF‐2‐IR correlates with staining for the high‐affinity FGF‐receptor 1. Intracerebroventricular injection of colchicine leads to the disappearance or substantial reduction of FGF‐2‐IR in the hypoglossal, facial, trigeminal motor, trochlear, and mesencephalic trigeminal nuclei. In contrast, FGF‐2‐IR appears in many perikarya of the red nucleus and the medial nucleus of the trapezoid body, whereas in control rats both nuclei showed immunostained fibers and almost no immunoreactive cell bodies. This dramatic change of FGF‐2‐IR could be explained by the ability of colchicine to block fast axonal transport. Cranial nuclei may internalize FGF‐2 at the periphery via high‐affinity receptors and retrogradely transport the molecule to their perikarya. The red nucleus and the medial nucleus of the trapezoid body may synthesize FGF‐2 and provide the growth factor to afferent or efferent neurons. The presence of FGF‐2 mRNA in brainstem extract and the absence of the FGF‐2 transcript in extracts of the hypoglossal nucleus corroborate this suggestion.The effect of colchicine on FGF‐2‐IR in the brainstem nuclei suggests that FGF‐2 could be specifically retrogradely transported in other cranial nuclei, in addition to the hypoglossal system. Together with the ability of FGF‐2 to stimulate neuronal survival, this result strongly supports the hypothesis that FGF‐2 is acting as a neurotrophic factor on specific central neuron populations. © 1995 Wiley‐Liss, Inc.
Inputs from identified jaw‐muscle spindle afferents to trigeminothalamic neurons in the rat: A double‐labeling study using retrograde HRP and intracellular biotinamide
Authors: Luo Pifu , Dessem Dean 
Published: January 2005

AbstractProjections from physiologically identified jaw‐muscle spindle afferents onto trigeminothalamic neurons were studied in the rat. Trigeminothalamic neurons were identified by means of retrograde transport of horseradish peroxidase from the ventroposteromedial nucleus of the thalamus. Labeled neurons were found contralaterally in the supratrigeminal region (Vsup), the trigeminal principal sensory nucleus, the ventrolateral part of the trigeminal subnucleus oralis, the spinal trigeminal subnuclei interpolaris and caudalis, the reticular formation, and an area ventral to the trigeminal motor nucleus (Vmo) and medial to the trigeminal principal sensory nucleus (AVM). Jaw‐muscle spindle afferents were physiologically identified by their increased firing during stretehing of the jaw muscles and intracellularly injected with biotinamide. Axon collaterals and boutons from jaw‐muscle spindle afferents were found in Vmo; Vsup; the dorsomedial part of the trigeminal principal sensory nucleus (Vpdm); the dorsomedial part of the spinal trigeminal subnuclei oralis, interpolaris (Vidm) and caudalis; the parvicellular reticular formation (PCRt); and the mesencephalic trigeminal nucleus. Trigeminothalamic neurons in Vsup, Vpdm, Vidm, PCRt, and AVM were associated with axon collaterals and boutons from intracellularly stained jaw‐muscle spindle afferents. Trigeminothalamic neurons in Vsup, Vpdm, Vidm, and PCRt were closely apposed by one to 14 intracellularly labeled boutons from jaw‐muscle spindle afferents, suggesting a powerful input to some trigeminothalamic neurons. These data demonstrate that muscle length and velocity feedback from jaw‐muscle spindle afferents is projected to the contralateral thalamus via multiple regions of the trigeminal system and implicates these pathways in the projection of trigeminal proprioceptive information to the cerebral cortex. © 1995 Wiley‐Liss, Inc.
Differences in the connectivity of rat pudendal motor nuclei as revealed by retrograde transneuronal transport of wheat germ agglutinin
Authors: Peshori Kavita R. , Erichsen Jonathan T. , Collins William F. 
Published: January 2005

AbstractBilateral coordinated activation of pudendal motoneurons is an essential component of penile reflexes in male rats. However, little is known about the intraspinal organization of these reflexes. In the present study, retrograde transneuronal transport of wheat germ agglutinin (WGA) was used to examine the organization of spinal motoneurons and putative interneurons mediating penile reflexes in adult male rats. Injection of WGA into the ventral bulbospongiosus muscle resulted in direct retrograde labeling of motoneurons in the ipsilateral dorsomedial (DM) nucleus and transneuronal labeling of ipsilateral and contralateral DM motoneurons. Motoneurons in the ipsilateral and contralateral dorsolateral (DL) nuclei were not labeled. WGA‐labeled putative interneurons were observed bilaterally, primarily in the ventromedial spinal gray matter extending dorsally to the central canal and the dorsal gray commissure. The number of transneuronally labeled putative interneurons increased with longer survival times. Injection of WGA into the ischiocavernosus muscle resulted in direct retrograde labeling of motoneurons in the medial subdivision of the ipsilateral DL nucleus. However, no WGA labeling was detected in motoneurons in the lateral subdivision of the ipsilateral DL nucleus, the contralateral DL nucleus, or the DM nuclei at any of the survival times studied (1–7 days). Only a small number of transneuronally labeled putative interneurons was observed in the ventrolateral gray matter at longer survival times (3–7 days). Thus, marked differences were observed between the DM and DL nuclei with respect to the transneuronal transport of WGA. These results are discussed with respect to the organization of the spinal circuits that mediate pudendal motor reflexes. © 1995 Wiley‐Liss, Inc.
Retinal ganglion cells in normal hamsters and hamsters with novel retinal projections. I. Number, distribution, and size
Authors: Métin Christine , Irons W. Andrew , Frost Douglas O. 
Published: January 2005

AbstractWe examined the number, spatial distribution, and size of ganglion cells in the retinae of normal Syrian hamsters and hamsters with retinal projections to the auditory and somatosensory nuclei of the thalamus, induced by neonatal surgery. As revealed by retrograde filling with horseradish peroxidase, there are about 64,600 contralaterally projecting retinal ganglion cells (RGCs) and 1,700 ipsilaterally projecting RGCs in the retinae of normal adult hamsters. Contralaterally projecting RGCs are distributed throughout the retina and have two local density peaks located within a central streak of high RGC density that is oriented approximately along the nasal‐temporal axis. RGC density falls above and below the central streak, with a steeper gradient towards the upper retina. Ipsilaterally projecting RGCs are diffusely distributed within a crescent at the inferotemporal retinal periphery and are most dense at the internal border of the crescent. The soma diameter of contralaterally projecting RGCs ranges from 6 to 25 μm; the diameter distribution is unimodal, with a peak in the 10–13 μm range and is skewed toward smaller values, with an elongated tail towards higher values. Contralaterally projecting RGCs tend to be smaller in regions of higher density. Ipsilaterally projecting RGCs tend to be larger than contralaterally projecting RGCs both globally and within the temporal crescent, and their size distributions tend to be less regular and less well related to local density.The retinae of neonatally operated hamsters with novel retinal projections to the auditory and somatosensory systems contain about one‐fourth the normal number of contralaterally projecting RGCs, whose relative density distribution is approximately normal despite the drastic reduction of absolute RGC density. The range and distribution of RGC soma diameters are similar in normal and neonatally operated hamsters, and, in operated as in normal hamsters, contralaterally projecting RGC somata tend to be smaller in regions of higher density.Our results in normal hamsters suggest a role for intraretinal mechanisms in the determination of RGC size. Our findings in neonatally operated hamsters suggest that, despite the reduced number of RGCs in these animals, the same types of RGCs are found in the retinae of normal and neonatally operated hamsters. © 1995 Wiley‐Liss, Inc.
Dynorphin opioid inhibition of cocaine‐induced, D1 dopamine receptor‐mediated immediatem‐early gene expression in the striatum
Authors: Steiner Heinz , Gerfen Charles R. 
Published: January 2005

AbstractNeurons in the striatum that project to the substantia nigra contain the opioid peptide dynorphin. Stimulation of D1 dopamine receptors results in increased expression of mRNA encoding dynorphin as well as expression of immediate‐early genes such as c‐fos in these neurons. Levels of dynorphin vary in different regions of the normal rat striatum, being highest in ventral and medial striatum. In a prior study, we have shown that both regional and temporal patterns of c‐fos induction following treatment with the indirect dopamine receptor agonist cocaine are inversely related to those of dynorphin expression. These results suggested that dynorphin is involved in regulating the responsiveness of these neurons to dopamine input. In the present experiments, we examined such a potential role for dynorphin by analyzing the influence of the dynorphin (kappa opioid receptor) agonist spiradoline on immediate‐early gene induction by cocaine, and we determined that this immediate‐early gene response is mediated by D1 dopamine receptors located in the striatum. As a marker of neuron activation, expression of c‐fos and zif 268 immediate‐early genes was assessed with quantitative in situ hybridization histochemistry. Results showed that (1) intrastriatal infusion of the D1 dopamine receptor antagonist SCH‐23390 (2.5–250 pmol) resulted in a dose‐dependent blockade of immediate‐early gene induction by cocaine (30 mg/kg); (2) systemic administration of the kappa opioid receptor agonist spiradoline (0.5–10.0 mg/kg) decreased cocaine‐induced expression of c‐fos and zif 268 mRNAs in striatum in a dose‐dependent manner; (3) intrastriatal infusion of spiradoline (1–50 nmol) also suppressed immediate‐early gene induction by cocaine, demonstrating that kappa opioid receptors located in the striatum mediate such an effect; and (4) systemic and intrastriatal administration of spiradoline also affected immediate‐early gene expression in cortex. These results demonstrate that, in striatum, immediate‐early gene induction by cocaine is a D1 dopamine receptor‐mediated process that is inhibited by activation of kappa opioid receptors. Therefore, these findings suggest that the striatal dynorphin opioid system acts directly and/or indirectly to inhibit dopamine input to striatonigral neurons through kappa opioid receptor‐mediated processes in the striatum. © 1995 Wiley‐Liss, Inc.
Thalamic distribution of projection neurons to the primary motor cortex relative to afferent terminal fields from the globus pallidus in the macaque monkey
Authors: Inase Masahiko , Tanji Jun 
Published: January 2005

AbstractTo examine quantitatively the pathway from the internal segment of the globus pallidus to the primary motor cortex through the thalamus, we compared the distribution of thalamocortical neurons projecting to the motor cortex with the distribution of afferent terminal fields from the pallidum in the ventrolateral nuclear group of the thalamus in four Japanese monkeys by using the anterograde and retrograde double‐labeling method. In each monkey, different fluorescent retrograde tracers (Fast Blue and Diamidino Yellow) were injected separately into the distal and proximal forelimb areas of the primary motor cortex after physiological mapping with intracortical microstimulation. In the same individual monkeys, an anterograde tracer, wheatgerm agglutinin conjugated to horseradish peroxidase, was injected into the internal segment of the globus pallidus after the forelimb part was identified physiologically.A small group of projection neurons to the distal and proximal representations of the motor cortex were found in the terminal fields from the pallidum, but a majority of the projection neurons were distributed outside the terminal area in the thalamus. These results confirm the existence of the pathway from the pallidum through the thalamus to the primary motor cortex, but also indicate that the primary motor cortex receives its major thalamic inputs from outside of the pallidal projection area, and that the pallidum sends its major outputs to nonprimary motor areas through the thalamus. © 1995 Wiley‐Liss, Inc.
Distribution of GAD‐like immunoreactivity in the retina and central visual system of Rana pipiens
Authors: Tyler Christopher J. , Fite Katherine V. , Devries Geert J. 
Published: January 2005

AbstractImmunohistochemistry was used to survey the distribution of glutamic acid decarboxylase (GAD), the synthesizing enzyme for gamma‐aminobutyric acid (GABA), throughout the visual system of the frog Rana pipiens. GAD‐like immunoreactivity (GAD‐LI) was assessed in the retina, in primary retinorecipient targets, and in thalamic nuclear groups postsynaptic to primary retinal terminal zones. Within the retina, the inner plexiform layer displayed intense GAD‐LI, but immunoreactivity was absent in the ganglion cell layer (GCL). Putative amacrine, bipolar, and horizontal cell somata were also labeled.Centrally, GAD‐LI was observed in all primary visual nuclei. Dense, GAD‐like immunoreactive punctate structures (puncta), presumably terminals, were observed in the pretectal nucleus lentiformis mesencephali, posterior thalamic neuropil, and uncinate neuropil. GADlike immunoreactive puncta were noted in several laminae of the optic tectum, with the highest concentrations located within the 9th and 8th laminae. Moderate numbers of GAD‐like immunoreactive puncta were found in the mesencephalic nucleus of the basal optic root, and two thalamic neuropils—corpus geniculatum and neuropil of Bellonci. The ventrolateral area, posterocentral nucleus, and posterolateral nucleus all contained sparse amounts of GAD‐LI.These observations suggest that GABA plays an important physiological role in all central visual areas of Rana pipiens. © 1995 Wiley‐Liss, Inc.
Precocious invasion of the optic stalk by transient retinopetal axons
Authors: Reese B. E. , Geller S. F. 
Published: January 2005

AbstractThis study demonstrates that the fetal optic nerve contains a conspicuous population of transient retinopetal axons. Implants of the carbocyanine dye, DiI, were made into the retina or diencephalon of fetal ferrets to label the retinopetal axons retrogradely or anterogradely, respectively, and sections were immunostained for β‐tubulin to label the early differentiating axons in the optic nerve.Dye implants into the optic nerve head, but not the retinal periphery, retrogradely labeled somata in the ventrolateral diencephalon, provided the implants were made before embryonic day (E) 30. When dye implants were made into the ventrolateral diencephalon, these same retinopetal axons were anterogradely labeled, coursing through the optic nerve but never invading the retina. The axons course as 2–5 fascicles from their cells of origin and turn laterally to enter the optic nerve where it joins the future hypothalamus. The retinopetal cells can be retrogradely labeled as early as E20, before optic axons have left the retina.The optic nerve and fiber layer are immunoreactive for β‐tubulin on E24 and thereafter, whereas on E20 and E22, they are immunonegative. Yet at these early embryonic ages, immunopositive fascicles of axons course from the diencephalon into the optic stalk, confirming the precocious nature of the retinopetal projection. Implants of dye made into the future optic nerve head at these very early stages also retrogradely label retinopetal cells in the future chiasmatic region. These cells are distributed primarily on the side ipsilateral to the midline, but a few can be found contralateral to it. Both these, as well as the retinopetal axons arising from the ventrolateral diencephalon, may serve a transient guidance function for later developing optic axons. © 1995 Wiley‐Liss, Inc.
Frog prohormone convertase PC2 mRNA has a mammalian‐like expression pattern in the central nervous system and is colocalized with a subset of thyrotropin‐releasing hormone‐expressing neurons
Authors: Pu Le‐Ping , Hayes William P. , Mill John F. , Ghose Shubroto , Friedman Theodore C. , Loh Y. Peng 
Published: January 2005

AbstractThe prohormone convertase (PC2) is expressed in the mammalian central nervous system (CNS) and has been shown to play an important role in the processing of certain neuropeptide precursors and prohormones at paired basic residues. Amphibian PC2 cDNA was recently cloned for the frog Xenopus laevis, and both its sequence and its pituitary expression pattern were shown to be very similar to those of mammalian PC2. To investigate further the function of PC2 in the vertebrate CNS, we used in situ hybridization histochemistry to localize the distribution of cells expressing PC2 mRNA in the frog brain and the spinal cord. The distribution of PC2‐expressing cells was also compared with that of cells expressing thyrotropin‐releasing hormone (TRH) mRNA or peptide. PC2‐expressing cells were detected in specific nuclei that were widely distributed in the frog CNS. In forebrain, telencephalic PC2 mRNA was found in the olfactory bulb, pallium, striatum, amygdala, and septum, and diencephalic PC2 mRNA was seen in the preoptic area, thalamus, and hypothalamus. More posteriorly, PC2 cells were localized to midbrain tegmentum, the torus semicircularis, and the optic tectum, as well as the cerebellum, brainstem, and spinal cord. Despite this wide distribution, steady‐state levels of PC2 mRNA were clearly different in various brain nuclei. Regions with higher levels showed good correspondence to areas shown by others in frog to contain large numbers of neuropeptideexpressing cells, including TRH cells. On the other hand, not all brain areas with high levels of TRH mRNA had high levels of PC2 mRNA. Localization studies combining in situ hybridization and immunocytochemistry showed that, at least in optic tectum and brainstem, PC2 mRNA and pro‐TRH peptide coexist. These findings suggest that pro‐TRH is processed by PC2 in some, but possibly not all, brain regions. Thus, different converting enzymes may be involved in pro‐TRH processing in different brain regions. © 1995 Wiley‐Liss, Inc.