bluuebunny/crossref_metadata_2025_split huggingface dataset:
Replacement of an inherited stretch receptor by a newly evolved stretch receptor in hippid sand crabs
Authors: Paul Dorothy H. , Wilson Linda J. 
Published: January 2005

AbstractPrimary sensory neurons that are motoneuron‐like in morphology and often nonspiking (transmit afferent signals as graded depolarizations) characterize an unusual type of stretch receptor in decapod crustaceans. Nonspiking and spiking receptors occur in similar positions at homologous joints in different species and have been presumed to be homologous, the spiking one considered „primitive.”︁ To better understand the evolutionary origin of these stretch receptors and why some are nonspiking, we examined the spiking telson‐uropod stretch receptors in the spiny sand crab Blepharipoda occidentalis (Albuneidae) and the squat lobster Munida quadrispina (Galatheidae) and compared them with the nonspiking telson‐uropod stretch receptor of the mole sand crab Emerita analoga (Hippidae). The position, morphology and responses to stretch of the sensory neurons, and the ultrastructure of the elastic strand portion of the receptor are similar in M. quadirspina and B. occidentalis, except that in B. occidentalis the receptor muscles are substantially smaller and the extracellular matrix of the elastic receptor strand is both more extensive and more organized, reminiscent of the ultrastructure of E. analoga's nonspiking receptor. We conclude that the spiking telson‐uropod stretch receptors of albuneids and galatheids are homologous. The differences in the ultrastructure of their receptor strands imply that the efficiency of coupling receptor length change to deformation of the dendritic termini increases in the order M. quadrispina < B. occidentalis < E. analoga.The spiking and nonspiking telson‐uropod stretch receptors differ anatomically in three major respects that appear to preclude their homology. (1) The receptor strands are on opposite sides of a conserved muscle. (2) The sensory somata are in different regions of the sixth abdominal ganglion: a lateral cluster of somata for the spiking sensory neurons and two medial clusters, one anterior, one posterior, for the nonspiking sensory neurons. (3) The neuropil projections of the sensory neurons are different. We conclude that the hippid's nonspiking telson‐uropod stretch receptor evolved de novo and not by modification of the ancestral anomuran telson‐uropod stretch receptor (which Hippidae have lost). 1994 Wiley‐Liss, Inc.
Rearing with monocular lid suture induces abnormal NADPH‐diaphorase staining in the lateral geniculate nucleus of cats
Authors: Günlük Alev E. , Bickford Martha E. , Sherman S. Murray 
Published: January 2005

AbstractWe investigated the changes in NADPH‐diaphorase staining that occur in the lateral geniculate nucleus of cats following rearing with monocular lid suture. This staining allows visualization of the synthesizing enzyme of nitric oxide, a neuromodulator associated with plasticity. In the lateral geniculate nucleus of normally reared cats, NADPH‐diaphorase exclusively labels the axons and terminals of an input from the parabrachial region of the brainstem; no geniculate cells in the A‐laminae are labeled. Early monocular lid suture has no obvious effect on the NADPH‐diaphorase staining of parabrachial axons. However, this lid suture results in the abnormal appearance of NADPH‐diaphorase staining for geniculate somata. These cells are located primarily in the nondeprived laminae. Double‐labeling experiments indicate that these cells with abnormal NADPH‐diaphorase reactivity are Y relay cells: NADPH‐diaphorase staining is found in cells retrogradely labeled from visual cortex; it is found in cells labeled with a monoclonal antibody for CAT‐301, which selectively targets Y cells; it is not found in cells labeled with an anti‐GABA antibody, which targets interneurons. Also, NADPH‐diaphorase labeled cells are among the largest cells in the nondeprived laminae, again suggesting that they are Y relay cells. We cannot suggest a specific mechanism for this induction of NADPH‐diaphorase labeling, but it does not seem to be due to abnormal binocular competition induced by the monocular lid suture. © 1994 Wiley‐Liss, Inc.
Cytochemical characteristics of neurons in the trigeminal mesencephalic nucleus of hatchling chicks
Authors: Scott Sheryl A. , Dinowitz Seth , Terhaar Kristen , Sherlock Diane , Campbell Maurice A. , Levine Dreania 
Published: January 2005

AbstractThe goal of the present study was to identify cytochemical markers characteristic of muscle afferents in hatchling chicks. To this end, we stained neurons in the trigeminal mesencephalic nucleus with a variety of markers that label subsets of neurons in avian dorsal root ganglia. We found that trigeminal mesencephalic neurons are surprisingly heterogeneous in their cytochemical make‐up, expressing, to varying degrees, substance P, cholecystokinin, carbonic anhydrase, calbindin D‐28k, parvalbumin, and S‐100β. Calbindin D28k and S‐100β appeared to be expressed equally in medial and lateral divisions of the trigeminal mesencephalic nucleus. In contrast, substance P‐ and cholecystokinin‐immunoreactive neurons were more abundant in the medial division, whereas carbonic anhydrase activity and parvalbumin immunoreactivity were stronger in the lateral division. We were unable to detect met‐enkephalin, neuropeptide Y, calcitonin gene‐related peptide, vasoactive intestinal peptide, somatostatin, γ‐aminobutyric acid, or tyrosine hydroxylase in the trigeminal mesencephalic nucleus. Moreover, these neurons did not appear to bind the lectin Dolichos biflorus agglutinin. The heterogeneity of expression of markers among trigeminal mesencephalic nucleus neurons, especially between neurons in the medial and lateral divisions, suggests that these neurons are functionally diverse.
Parvalbumin‐containing GABAergic neurons in the basal ganglia output system of the rat
Authors: Rajakumar N. , Elisevich K. , Flumerfelt B. A. 
Published: January 2005

AbstractThe output of the basal ganglia is directed through the entopeduncular nucleus (EPN) and the substantia nigra pars reticulata (SNR) and pars lateralis (SNL), which provide a γ‐aminobutyric acidergic (GABAergic) projection to various nuclei of the thalamus and brainstem. Although many neurons within the SNR and EPN have been described as modality specific, the morphological and neurochemical similarities preclude their precise identification. In the present study, the immunocytochemical localization of parvalbumin, a calcium‐binding protein, is used in combination with axonal tracing to verify neuronal heterogeneity within the SNR, SNL, and EPN. The results reveal that the majority of neurons in all three centers contain parvalbumin. The parvalbumin‐containing neurons are distributed in the caudal two‐thirds of the EPN, the rostral part of the SNL, and the lateral two‐thirds of the entire rostrocaudal extent of the SNR, the areas involved in sensorimotor function of the basal ganglia. Moreover, the negrothalamic, nigrocollicular, and EPN‐thalamic neurons possess parvalbumin immunoreactivity, whereas the EPN‐habenular neurons are devoid of parvalbumin immunoreactivity. The results indicate a neurochemical heterogeneity within the GABAergic output neurons of the basal ganglia and suggest that the parvalbumin‐containing neurons of the SNR, SNL, and EPN are the tonically active output neurons that form a major link in the disinhibitory neuronal circuit of the basal ganglia, especially that concerned with sensorimotor function. © 1994 Wiley‐Liss, Inc.
Evidence for survival of the central arbors of trigeminal primary afferents after peripheral neonatal axotomy: Experiments with galanin immunocytochemistry and Di‐I labelling
Authors: White Fletcher A. , Hoeflinger Brian F. , Chiaia Nicolas L. , Bennett‐Clarke Carol A. , Crissman Robert S. , Rhoades Robert W. 
Published: January 2005

AbstractStudies employing axoplasmic transport techniques have suggested that the central arbors of vibrissae‐related primary afferents are rapidly and permanently lost from the trigeminal (V) brainstem complex after transection of the intraorbital nerve (ION). The present study reexamined this issue using immunocytochemistry for galanin (GAL) and anterograde labelling with Di‐I to evaluate V brainstem organization in rats that sustained damage to the ION or individual vibrissae follicles in infancy or adulthood. After adult nerve damage, GAL‐positive fibers are increased in layers I and II of V subnucleus caudalis (SpC). This was apparent by 3 days after the lesion. In rats that sustained nerve damage at birth (PO), GAL immunoreactivity (IR) appeared throughout the V brainstem complex and had a patchy distribution similar to that of vibrissae‐related V primary afferents in normal rats. Increased GAL‐IR in rostral portions of the V brainstem complex was observed in rats that sustained ION damage as late as P14. Additional experiments in which nerve damage was followed by destruction of the V ganglion demonstrated that this GAL‐IR was contained in primary afferents. Damage to single vibrissa follicles or to a row of follicles produced a single patch or row of GAL‐IR terminals in the somatotopically appropriate portion of the ipsilateral V brainstem complex. Di‐I labelling in neonatally nerve‐damaged rats demonstrated that primary afferent axons filled the central territory normally innervated by this nerve and that their terminal distribution was patchy. These results suggest that the V ganglion cells that survive neonatal axotomy may retain somatotopically organized projections to the V brainstem complex for at least a limited postnatal period.
Differential physiology and morphology of motor axons to ventral longitudinal muscles in larval Drosophila
Authors: Kurdyak P. , Atwood H. L. , Stewart B. A. , Wu C.‐F. 
Published: January 2005

AbstractMorphological and physiological characteristics of the two major motor axons supplying the commonly studied ventral longitudinal muscle fibers (6 and 7) of third‐instar Drosophila melanogaster larvae were investigated. The innervating terminals of the two motor axons differ in the size of their synapse‐bearing varicosities. The terminal with the larger varicosities also fluoresces more brightly when stained with the vital fluorescent dye 4‐(4‐diethylaminotyryl)‐N‐methylpyridinium iodide (4‐Di‐2‐Asp) and occupies a larger total contact area on the muscle fiber. Through selective simultaneous recording of synaptic currents from identified boutons in living preparations during elicitation of synaptic potentials, it was shown that the axon with the smaller varicosities generates a large excitatory junction potential (EJP) in muscle 6 and that the axon with the larger varicosities generates a smaller EJP. Short‐term facilitation is more pronounced for the smaller EJP. In preparations treated with 4‐Di‐2‐Asp, the fluorescence of smaller varicosities increases with stimulation that elicits the large EJPs, indicating an acitivity‐dependent entry of calcium that enhances mitochondrial fluorescence. The differences in morphology and physiology of the two axons are similar to, though less pronounced than, those observed in „phasic”︁ and „tonic”︁ motor axons of crustacens. © 1994 Wiley‐Liss, Inc.
Morphological evidence for the presence of ipsilateral inferior olivary neurons during postnatal development of the olivocerebellar projection in the rat
Authors: López‐Roman Antonio , Armengol José Angel 
Published: January 2005

AbstractThe presence of ipsilateral inferior olivary neurons during postnatal development of the olivocerebellar projection in the rat was investigated by two in vitro axonal tracing methods and by the axotomy of one olivocerebellar tract. The experiments were carried out before (P1), during (P5–P10) and after (P20) the period of multiple innervation of Purkinje cells by climbing fibers. According to present results: (1) ipsilateral inferior olivary neurons are distributed, on all analyzed days, throughout the entire inferior olive; (2) cell counts after axotomy experiments demonstrated that they represent a small population of inferior olivary neurons, whose number oscillated between 271 ± 30 in young animlas (pedunculotomized at P1 and killed at P7) and 26 ± 12 in older ones (pedunculotomized at P20 and killed at P40). This experiment confirmed that most of these neurons are eliminated during the regressive events that take place during normal development of the olivocerebellar projection; and (3) few ipsilateral inferior olivary neurons, however, survive at P40, but their significance is still unclear. © 1994 Wiley‐Liss, Inc.
Early development of cerebellar afferent systems that contain corticotropin‐releasing factor
Authors: Cummings Sharon L. , Young W. Scott , King James S. 
Published: January 2005

AbstractCorticotropin‐releasing factor (CRF) and CRF binding sites have been described in the cerebellum of several species, including the North American opossum (Didelphis marsupialis virginiana), the species used in the present study. Iontophoretic application of this peptide in the adult cerebellum enhances the spontaneous and amino acid‐induced firing rate of Purkinje cells and overcomes the GABA‐induced suppression of Purkinje cell activity. The present account provides immunohistochemical evidence for the localization of CRF in the North American opossum within developing axons and their growth cones prior to the formation of the Purkinje cell and granule cell layers. CRF mRNA is present on postnatal day (PD) 1 within the internal migratory stream of the ventral lateral medulla, which contains migrating olivary neurons, and within the ventral medulla in the region, where inferior olivary neurons first aggregate to form the inferior olivary complex. The olivary complex can first be identified on PD2 and is well defined by PD3. CRF‐immunoreactive axons are evident within the cerebellar primordium on PD4 and penetrate the nascent Purkinje cell layer between PD14 and PD26. By PD26, CRF‐immunoreactive puncta are organized within the Purkinje cell layer as parasagittal bands. Thus, olivary neurons express CRF mRNA prior to the time that the first CRF‐labeled axons are present in the cerebellar anlage (PD4), suggesting that olivary axons are among the first to reach the developing cerebellum. Coincident (PD1–3) with the early transcription of CRF mRNA in the inferior olive, cells in the medullary reticular formation (PD1) and locus coeruleus (PD2) also transcribe CRF mRNA. These brainstem sites also could provide CRF‐immunoreactive axons to the developing cerebellum; however, based on the results of this study and correlative data reported in the literature, we propose that the primary source of early‐arriving CRF fibers is the inferior olivary complex. The early arrival of CRF‐containing axons in the cerebellum prior to synaptogenesis and migration of both granule cells and Purkinje cells suggests a role for this peptide in target recognition and synaptic organization. © 1994 Wiley‐Liss, Inc.
TrkA‐immunoreactive profiles in the central nervous system: Colocalization with neurons containing p75 nerve growth factor receptor, choline acetyltransferase, and serotonin
Authors: Sobreviela Teresa , Clary Douglas O. , Reichardt Louis F. , Brandabur Melanie M. , Kordower Jeffrey H. , Mufson Elliott J. 
Published: January 2005

AbstractThe present investigation used an antibody directed against the extracellular domain of the signal transducing nerve growth factor recepto, trkA, to reveal immunoreactive perikarya or fibers within the olfactory bulb and tubercle, cingulate cortex, nucleus accumbens, striatum, endopiriform nucleus, septal/diagonal band complex, nucleus basalis, hippocampal complex, thalamic paraventricular and reuniens nuclei, periventricular hypothalamus, interpeduncular nucleus, mesencephalic nucleus of the fifth nerve, dorsal nucleus of the lateral lemniscus, prepositus hypoglossal nucleus, ventral cochlear nucleus, ventral lateral tegmentum, medial vestibular nucleus, spinal trigeminal nucleus oralis, nucleus of the solitary tract, raphe nuclei, and spinal cord. Colocalization experiments revealed that virtually all striatal trk‐Aimmunoreactive neurons (> 99%) coexpressed choline acetyltransferase (ChAT) but not p75 nerve growth factor receptor (NGFR). Within the septal/diagonal band complex virtually all trkA neurons (> 95%) coexpressed both ChAT and p75 NGFR. More caudally, dual stained sections revealed numerous trkA/ChAT (> 80%) and trkA/p75 NGFR (> 95%) immunoreactive neurons within the nucleus basalis. In the brainstem, raphe serotonergic neurons (45%) coexpressed trkA. Sections stained with a pan‐trk antibody that recognizes primarily trkA, as well as trkB and trkC, labeled neurons within all of these regions as well as within the hypothalamic arcuate, supramammilary, and supraoptic nuclei, hippocampus, inferior and superior colliculus, substantia nigra, ventral tegmental area of T'sai, and cerebellar Purkinje cells. Virtually all of these other regions with the exception of the cerebellum also expressed pan‐trk immunoreactivity in the monkey. The widespread expression of trkA throughout the central neural axis suggests that this receptor may play a role in signal transduction mechanisms linked to NGF‐related substances in cholinergic basal forebrain and noncholinergic systems. These findings suggest that pharmacological use of ligands for trkA could have beneficial effects on the multiple neuronal systems that are affected in such disorders as Alzheimer's disease. © 1994 Wiley‐Liss, Inc.
Neurotrophin receptor mRNA expression defines distinct populations of neurons in rat dorsal root ganglia
Authors: Wright D. E. , Snider W. D. 
Published: January 2005

AbstractThe biological actions of neurotrophins are mediated by specific neurotrophin receptor tyrosine kinases (Trks). A low‐affinity nerve growth factor (NGF) receptor, p75, appears to modulate sensitivity to neurotrophins in some neuronal populations. It has been recently demonstrated that genes encoding members of the Trk family are expressed in distinct patterns in the dorsal root ganglia DRG; Mu et al. [1993] (J. Neurosci. 13:4029–4041). However, the extent to which different neurotrophin receptor genes are coexpressed by individual DRG neurons is unknown. The question of coexpression is important since the expression of more than one member of the trk family by DRG neurons would suggest the potential for regulation by multiple neurotrophins. To address this question, a combination of isotopic and colorimetric in situ hybridization was performed on rat thoracic DRG using riboprobes specific for trk A, trkB, trkC, and p75. We show here that neurons that express trkA are largely distinct from those that express trkC, although there is a small subpopulation that expresses both of these genes. We also show that there is a distinct population of DRG neurons that expresses trkB and does not coexpress either trkA or trkC. P75 is expressed in almost all neurons that express trkA or trkB, but is coexpress in only 50% of trkC‐expressing neurons. Importantly, p75 is not expressed in DRG neurons independent of trk expression. Finally, a subpopulation of DRG neurons does not express any of the neurotrophin receptor mRNAs.Our results demonstrate that there are distinct populations of DRG neurons that express each member of the neurotrophin receptor tyrosine kinase family. Our findings of extensive colocalization of p75 with trkA and trkB lend support to the idea that p75 is important in mediating the actions of NGF and brain‐derived neurotrophic factor on DRG neurons. Interestingly, however, p75 expression is clearly unimportant for a subpopulation of neurons that require neurotrophin‐3. The fact that p75 is not expressed in the absence of trkA, trkB, or trkC suggests that the function of p75 is closely related to functions of the known neurotrophin receptor tyrosine kinases. Finally, our results suggest that a significant percentage of DRG neurons may be regulated by non‐neurotrophin neuronal growth factors. © 1995 Willy‐Liss, Inc.
Lack of topography in the spinal cord projection of the rabbit soleus muscle
Authors: Cramer Karina S. , van Essen David C. 
Published: January 2005

AbstractSeveral mammalian muscles in the limb and trunk receive topographically organized innervation from spinal cord motor neurons. Some muscles in which topographic innervation has been demonstrated have a sheet‐like architecture; others are compartmentalized and/or have more than one origin. An interesting question is whether topography is related to these anatomical features, or whether it occurs as a general consequence of the development of innervation.To address this question, we examined the pattern of projections to the soleus muscles, which lacks these anatomical features. Intracellular recordings of endplate potentials in early and intermediate age rabbits were used to assess the spinal origin of inputes to two distinct regions of the muscle. Both regions were innervated by both rostral and caudal portions of the motor pool. These experiments also showed that individual muscle fibers frequently receive separate inputs arising from widely separated regions of the motor pool. In another set of experiments, physiological measurements of tension overlap in young, polyinnervated muscles showed that the relative positions of motor neurons in the spinal cord do not correlate with the extent to which motor units share muscle fibers. In a third set of experiments, motor neurons were retrogradely labeled following local injections of tracer into muscle. Small and large local injections resulted in comparably dispersed labeling of motor neurons within the motor pool. Moreover, the rostrocaudal position of labeled neurons was not correlated with the position of the injection site within the muscle. Together, these results provide evidence that the soleus muscle is not topographically innervated. Furthermore, an examination of several age groups suggests that the innervation pattern in this muscle is not altered by postnatal synapse elimination. © 1995 Willy‐Liss, Inc.
Structure and innervation of the sensory organs on the snout of the star‐nosed mole
Authors: Catania Kenneth C. 
Published: January 2005

AbstractThe star‐nosed mole possesses a conspicuous specialization of its snout in the form of 22 fleshy appendages that fan out from around the nostrils. These appendages are used by the mole to explore its underground environment and are repeatedly brought into contact with objects of interest to the mole. This report describes the structure, innervation, and distribution of the sensory organs on the star of the star‐nosed mole and briefly describes the behavioral use of the star. Each of the 22 appendages of the star is covered with a continuous array of Eimer's organs. These sensory receptors are modifications of the epidermal surface that take the form of bulbous papillae. Each Eimer's organ contains a column or stack of epidermal cells accompanied by nerve processes that originate from myelinated fibers in the underlying dermis. These neural processes travel through the cell column and form terminal swellings just below the outer layer of keratinized epidermis. Each Eimer's organ also contains a single Merkel cell‐neurite complex within the cell column and a single lamellated corpuscle immediately below the cell column in the connective tissue of the dermis. There are approximately 30,000 Eimer's organs on the snout of this mammal, making this structure perhaps the most sensitive tactile organ yet discovered for its size. The segregation of these organs to individual appendages, not unlike the fingers of primates. affords an intriguing model for the study of somatosensory systems in mammals. © 1995 Willy‐Liss, Inc.