bluuebunny/crossref_metadata_2025 huggingface dataset:
Gamma‐aminobutyric acid in the nervous system of a planarian
Authors: Eriksson Krister S. , Panula Perm
Published: January 2005

The amino acid gamma‐aminobutyric acid (GABA) is an important inhibitory neurotransmitter in both vertebrates and invertebrates. Despite this, no reports of GABA in flatworms have to date been published. We have studied the presence of GABA in the planarian Dugesia tigrina with immunocytochemical methods and high‐pressure liquid chromatography. Fibers showing GABA‐like immunoreactivity (GABA‐IR) were present in abundance in the longitudinal nerve cords and lateral nerves. GABA‐IR was revealed in fibers forming commissures in the brain. The ventral part of the subepidermal plexus showed GABA‐IR. No cell somata containing GABA‐IR could be identified with certainty.

The chromatographic analysis showed that the average GABA concentration in D. tigrina is 533.6 pmol/mg protein. This is substantially higher than the concentrations of dopamine (62.87 pmol/mg) and serotonin (233.20 pmol/mg). An enzyme assay confirmed the capacity for GABA‐synthesis in D. tigrina. The results indicate that GABA‐containing neurons appeared earlier in evolution than was previously thought and that GABA may serve an important role already in the flatworms. © 1994 Wiley‐Liss, Inc.
Coordination of gaze shifts in primates: Brainstem inputs to neck and extraocular motoneuron pools
Authors: Robinson Farrel R. , Phillips James O. , Fuchs Albert F.
Published: January 2005

To, determine whether there are brainstem regions that provide common input to the motoneurons that move both the head and the eyes, we injected wheat germ agglutinin‐horseradish peroxidase complex (WGA‐HRP) into neck motoneuron pools at spinal level C2 (N = 3) and extraocular motoneuron pools in the abducens (N = 1) and oculomotor/trochlear (N = 1) nuclei of rhesus and fascicularis macaques. We also injected WGA‐HRP into spinal level C5‐7 (N = 1) of a fascicularis macaque for comparison.

After injections into C2, we observed retrogradely labeled cells in the ventral reticular formation (NRV), the gigantocellular‐reticular formation (NRG), and both the oral (NRPO) and the caudal (NRPC) divisions of the paramedian pontine reticular formation (PPRF). There was also a column of labeled cells in the cuneate reticular nucleus (NCUN) just lateral to the ipsilateral periaqueductal gray (PAG). This column extended rostrally into the central mesencephalic reticular formation (CMRF). In addition, there were labeled cells in the region ventral and caudal to the rostral interstitial nucleus of the MLF (riMLF), the area lateral to the interstitial nucleus of Cajal (INC), and the ventral part of the lateral vestibular nucleus (LVN) and lateral part of the medial vestibular nucleus (MVN). There were also a few labeled cells in the fastigial (FN) and interposed (IN) nuclei of the cerebellum but very few in the superior colliculus (SC). In contrast, the injection into C5‐7 labeled many cells in the lateral vestibular nucleus (LVN) and very few in FN or IN.

Injecting WGA‐HRP into the abducens nucleus and the surrounding tissue labeled many cells in SC, PPRF, MVN, FN, and nucleus prepositus hypoglossi (NPH). Injecting into the oculomotor/trochlear nuclei and nearby tissue labeled cells in SC, INC, riMLF, FN, IN, MVN, and superior vestibular nucleus (SVN).

Structures that project to both neck and eye motoneuron pools, and therefore probably participate in both head and eye movements, include the lateral part of the MVN and both NRPO and NRPC in the PPRF. Those that project primarily to neck motoneurons in C2 include the NRV, the NRG, and the NCUN‐CMRF column. Those projecting exclusively to extraocular nuclei include the NPH, INC, riMLF, NRPD, and SC. We use these data to propose a scheme for control of combined eye‐head movements in monkeys. © 1994 Wiley‐Liss, Inc.
Transient increase in expression of GAD65 and GAD67 mRNAs during postnatal development of rat spinal cord
Authors: Ma Wu , Behar Toby , Chang Lisa , Barker Jeffery L.
Published: January 2005

Gamma‐aminobutyric acid (GABA) is thought to be one of the classic neurotransmitters acting as a developmental signal. To understand the role for GABA in development, we investigated the expression of transcripts encoding two forms of the GABA‐synthesizing enzyme glutamate decarboxylase (GAD65 and GAD67) in the cervical enlargement of the rat spinal cord at successive postnatal days—P0, P7, P14, P21, and P90 (adult)—by using in situ hybridization histochemistry. Cells hybridized with two oligonucleotide probes designed to detect GAD65 and GAD67 mRNAs were widely distributed in all laminae, except in motoneurons of the spinal cord. The integrated densities of hybridization signals were measured across all layers of the gray matter. The relative number of GAD mRNA‐labeled cells was determined within each of four regions: laminae I–;III, laminae IV–VI, laminae VII and VIII, and lamina X. There was a transient increase in both the integrated density and the relative number of hybridized cells between P7 and P14, after which there was a marked decline to adult levels (lowest). An overall decrease in the number of GAD mRNA‐labeled cells was evident in all layers, but a dramatic drop occurred in a subpopulation of cells within ventral portions of the spinal cord. The distribution patterns and postnatal changes in expression of the mRNAs encoding GAD65 and GAD67 were similar and closely paralleled reported changes in the abundance of GAD65 and GAD67 proteins and their product, GABA. Transient increases in GAD mRNA expression during the early postnatal period coincide with, and may be linked to, synapse formation and synapse elimination of the developing spinal cord. © 1994 Wiley‐Liss, Inc.
Neurochemical compartmentalization of the globus pallidus in the rat: An immunocytochemical study of calcium‐binding proteins
Authors: Rajakumar N. , Rushlow W. , Naus C. C. G. , Elisevich K. , Flumerfelt B. A.
Published: January 2005

The globus pallidus external segment forms a major target center of the mammalian striatum which is characterized by neurochemically distinct compartments. The present study was undertaken to determine if a corresponding compartmentalization exists within the globus pallidus external segment in the rat. Immunocytochemical examination of the calcium‐binding proteins parvalbumin and calbindin D28kDa, which are present in neurons of the striatal matrix compartment, was employed. The results indicate three neurochemically distinct compartments within the globus pallidus external segment: (1) an area in the medial aspect of the entire length of the globus pallidus that contains dense immunoreactivity for calbindin D28kDa; (2) a narrow rim at the striatopallidal junction in the rostral two‐thirds of the globus palidus that contains calbindin D28kDa immunoreactivity designated as the “border zone” of the globus pallidus; and (3) an area between these two zones showing very poor immunoreactivity for calbindin D28kDa but containing parvalbumin immunoreactive neurons.

The calbindin D28kDa immunoreactive border zone corresponds to the area of the globus pallidus where striatal inputs converge extensively, whereas the rest of the nucleus is involved in segregated, topographically organized pathways. Parvalbumin‐containing neurons are involved in the propagation of striatal output related to striosomal and sensorimotor aspects of basal ganglia function. The present results also indicate that calbindin D28kDa immunoreactivity is completely absent from striosomal neurons and is therefore a useful marker for striatal compartments. © 1994 Wiley‐Liss, Inc.
Early embryonic expression of a 60‐kD glycoprotein in the developing nervous system of the lobster
Authors: Garzino Veronique , Reichert Heinrich
Published: January 2005

To investigate the developmental processes that generate the crustacean nervous system, we used a monoclonal antibody that recognises an antigen that is expressed in the developing embryonic nervous system of the lobster, Homarus gammarus. Expression of this antigen commences early in embryogenesis, occurs in all parts of the embryonic central and peripheral nervous systems, and continues into adulthood. Initial expression in the central nervous system correlates with the onset of neuronal process outgrowth. Light microscopic analysis shows that the antigen is found surrounding the cell bodies and processes of all neurons. Biochemical analysis indicates that the antigen, is a glycoprotein with an apparent molecular weight of 60 kD. Due to the early embryonic onset of its expression, this antigen is a useful cellular label for visualisation of‐ pattern formation in the developing nervous system; this is documented in detail for the developing stomatogastric nervous system. The fact that the 60‐kD antigen is expressed early in embryogenesis throughout the nervous system suggests that it might play an important role in the development of the lobster nervous system. © 1994 Wiley‐Liss, Inc.
Morphological study of the rostral interstitial nucleus of the medial longitudinal fasciculus in the monkey, Macaca mulatta by Nissl, Golgi, and computer reconstruction and rotation methods
Authors: Crossland W. J. , Hu X. J. , Rafols J. A.
Published: January 2005

We have studied the morphology of silver‐impregnated neurons (rapid Golgi technique) in the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF), a center involved in the control of vertical and torsional saccadic eye movements. This morphological study of riMLF neurons in the rhesus monkey was undertaken to further our understanding of the functional circuitry of the oculomotor system. Our study employed Nissl, Golgi, and computer‐ assisted methods. The cytoarchitectonic boundaries of the riMLF and its relationships to neighboring structures were determined in both Nissl and Golgi preparations. Five (I–V) distinct morphological types of riMLF neurons were distinguished in the Golgi impregnations on the basis of soma size, dendritic size, numbers of primary dendrites, number of dendritic branch points, as well as form, number, and distribution of dendritic appendages. Type I neurons impregnated most frequently and had the most extensive and highly branched dendritic tree. Type II neurons displayed thick dendrites with complex dendritic appendages, but the dendritic tree was much more compact than that of type I cells. Type III and type V cells had fusiform somas and relatively unbranched dendritic trees but differed greatly in size as well as dendritic morphology. The type IV cell was the smallest neuron and had many characteristics of the local interneurons found in other thalamic, subthalamic, hypothalamic, and midbrain centers. The type V was the largest neuron, least frequently impregnated, and found only at rostral riMLF levels. Digitized reconstructions of each type of neuron were rotated by the computer, which revealed that the dendritic trees of types I, III, and V occupy a disk‐like compartment in the riMLF neuropil. In contrast, the trees of types II and IV occupy a roughly spherical compartment. We suggest that three of the cell types are well suited for specific purposes: type II cells for receiving, topographically organized inputs that contain spatial information, type I cells for short‐lead burst neuron output to the motor neurons or other premotor centers, and type IV cells for inhibitory inputs to type I cells. © 1994 Wiley‐Liss, Inc.
Morphological maturation of thalamic neurons as studied in fetal neural transplants
Authors: Cadusseau Josette , Rapisardi Salvatore , Peschanski Marc
Published: January 2005

This study attempts to determine whether fetal thalamic neuroblasts from rat embryos (embryonic age 15 days) labeled with horseradish peroxidase (HRP) can differentiate into their normal dendriticphenotype when transplanted as a cell suspension into a lesioned site in the adult somatosensory thalamus. The HRP labeling provided a Golgi‐like staining of numerous neurons up to 12–14 days after transplantation. There were three main results. (1) As early as 2 days after transplantation three morphologic cell types were observed: Two were bipolar and the third multipolar. These cellular profiles are characteristic of adult ventroposterolateral, reticular, and ventroposteromedial neurons and suggest that transplanted neurons can take shape in the absence of specific arrangements of afferent fibers. (2) The initial stage of dendritic growth was characterized by numerous growing specializations and consisted of a rapid, arborizing growth that appeared to proceed at an accelerated rate relative to normal development. During the later stage, which was characterized by the great reduction of growing specializations, dendritic remodeling resulted in a simpler morphology, and the transplanted neurons did not achieve an adult morphology. (3) Putative axons exhibiting growth cones were present in impressive densities in the transplants, and a number of them grew into the neuron‐depleted host thalamus. A very small number of axons grew into host gray matter outside the lesioned area, indicating that neurodegenerative areas provide a better substrate for neurite outgrowth than, intact tissue. In rare instances axons were visible in the internal capsule, indicating that the biochemical inhibition provided by mature myelin and oligodendrocytes may not be an absolute obstacle to axonal growth. © 1994 Wiley‐Liss, Inc.
Cone bipolar cells as interneurons in the rod, pathway of the rabbit retina
Authors: Strettoi Enrica , Dacheux Ramon F. , Raviola Elio
Published: January 2005

In the mammalian retina, rod signals are transmitted by rod bipolars to the narrow‐field, bistratified (AII) amacrine cell. This neuron, in turn, makes gap junctions with the axonal arborization of cone bipolar cells that reside in the vitreal half (sublamina b) of the inner plexiform layer (IPL). After examining rod bipolars and AII amacrines in the rabbit retina, we have now reconstructed from electron micrographs of continuous series of thin sections the synaptic connections of the axonal arborizations of cone bipolar cells that make the highest number of gap junctions with AII amacrines.

These axonal arborizations were narrowly confined to stratum 4 (S4) of the IPL and made ribbon synapses to dyads of postsynaptic‐dendrites that belonged to either ganglion or amacrine cells. In the population of postsynaptic processes, 30% were ganglion cell dendrites. These dendrites were probably originating, at least in part, from on‐center ganglion cells because their course was confined to sublamina b of the IPL. Of the remaining postsynaptic processes, 51.7% belonged to amacrine cells and 18.3% were not identified. Among the postsynaptic amacrine cell processes, 33.3% returned a reciprocal synapse onto the cone bipolar endings. These reciprocal synapses represented 21.3% of the total input onto the axonal arborizations, the remaining fraction (78.7%) arising from a heterogeneous population of amacrine dendrites that were purely presynaptic to the cone bipolars endings. Pre‐ and postsynaptic amacrines were part of several distinct microcircuits which suggest complex local processing of both rod and cone signals.

Thus, the cone bipolars that make gap junctions with AII amacrines in sublamina b of the rabbit IPL exhibit a substantial output onto ganglion cells. This fact, in conjunction with our previous observations that in this sublamina ganglion cells receive negligible input from rod bipolars and AII amacrines, demonstrates that in the rabbit cone bipolars represent a necessary link in the pathway followed by rod signals to enter on‐center ganglion cells. Thus, rod and cone signals ultimately share the same integrating mechanisms and converge onto the same set of ganglion cells. © 1994 Wiley‐Liss, Inc.
Peptidies related to the Diploptera punctata allatostatins in nonarthropod invertebrates: An immunocytochemical survey
Authors: Smart D. , Johnston C. F. , Curry W. J. , Williamson R. , Maule A. G. , Skuce P. J. , Shaw C. , Halton D. W. , Buchanan K. D.
Published: January 2005

The allatostatins are a family of peptides isolated originally from the cockroach, Diploptera punctata. Related peptides have been identified in Periplaneta Americana and the blowfly, Calliphora vomitoria. These peptides have been shown to be potent inhibitors of juvenile hormone synthesis in these species. A peptide inhibitor of juvenile hormone biosynthesis has also been isolated from the moth, Manduca sexta; however, this peptide has no structural homology with the D. punctata‐type allatostatins. Investigations of the phylogeny of the D. punctata allatostatin peptide family have been started by examining a number of nonarthropod invertebrates for the presence of allatostatin‐like molecules using immunocytochemistry with antisera directed against the conserved C‐terminal region of this family. Allatostatin‐like immunoreactivity (ALIR) was demonstrated in the nervous systems of Hydra oligactis (Hydrozoa), Moniezia expansa (Cestoda), Schistosoma mansoni (Trematoda), Artioposthia triangulate (Turbellaria), Ascaris suum (Nematoda), Lumbricus terrestris (Ohgochaeta), Limax pseudoflavus (Gastropoda), and Eledone cirrhosa (Cephalopoda). ALIR could not be demonstrated in Ciona intestinalis (Ascidiacea). These results suggest that molecules related to the allatostatins may play an important role in nervous system function in many invertebrates as well as in insects and that they also have an ancient evolutionary lineage. © 1994 Wiley‐Liss, Inc.
Localization of salmon gonadotropin‐releasing hormone mRNA and peptide in the brain of atlantic salmon and rainbow trout
Authors: Bailhache Thierry , Arazam Aïcha , Klungland Helge , Aleström Peter , Breton Bernard , Jego Patrick
Published: January 2005

The decapeptide gonadotropin‐releasing hormone (GnRH) is a key hormone for the central regulation of reproduction. The distribution of salmon GnRH (sGnRH), which is the major form in salmonids, has been studied in different fish species by immunocytochemistry. Discrepancies in data concerning the distribution of sGnRH perikarya led us to investigate this problem in two species, the Atlantic salmon and the rainbow trout, with in situ hybridization of sGnRH messenger, a highly specific molecular tool. By Northern blot analysis, the rainbow trout sGnRH messenger appears to be about 500 bases in length, which is close to those isolated from Atlantic salmon or masu salmon and characterized previously, In situ hybridization with riboprobes generated with Atlantic salmon sGnRH cDNA demonstrated that sGnRH perikarya are restricted to the ventral part of olfactory bulbs, telencephalon, and preoptic area. They are distributed on a nearly continuous line extending from the olfactory bulbs to the preoptic area in both salmonid species studied.

Despite the presence of GnRH‐like immunoreactivity in the preoptic magnocellular nucleus (NPOm) and in the tegmentum of the midbrain (MT), the sGnRH mRNA is not present in these two structures. Stained cells in NPOm could be target cells for GnRH and immunoreactive neurons in MT are likely to be chicken GnRH‐II containing cells. Our study not only gives a precise distribution of the sGnRH system in two salmonids, Atlantic salmon and rainbow trout, but also clarifies the ambiguous data published up to now in rainbow trout. © 1994 Wiley‐Liss, Inc.
VGF expression in the brain
Authors: Van Den Pol Anthony N. , Bina Keshavan , Decavel Chantal , Ghosh Prabhat
Published: January 2005

VGF is a neuronal polypeptide first identified as a cDNA clone in a gene library from nerve growth factor‐stimulated PC12 cells. In the present paper, the expression of VGF is examined for the first time throughout the adult rat central nervous system with immunocytochemistry and Northern blot analysis. VGF RNA was found in all brain regions studied, including hypothalamus, hippocampus, cerebellum, olfactory bulb, and cortex. In contrast to the relatively strong immunostaining of hypothalamic neurons, the level of VGF RNA expression in the hypothalamus was relatively low in comparison with other brain regions. With the aid of antisera raised against bacterially produced recombinant proteins containing parts of the VGF sequence, immunoreactive neurons were detected throughout the brain, including regions of the olfactory tubercle, caudate‐putamen, thalamus, cortex, amygdala, hypothalamus, mid brain, and hippocampus. VGF‐immunoreactive neurons did not contain detectable amounts of nerve growth factor receptor; other neurons that showed nerve growth factor receptor immunoreactivity expressed no VGF immunoreactivity. The lack of colocalization of VGF and nerve growth factor receptor suggests that, unlike expression in PC12 cells, VGF expression in neurons from the central nervous system does not require nerve growth factor stimulation. Within the hippocampus, the location of VGF‐immunoreactive cells was suggestive of inhibitory interneurons. ‐VGFimmunoreactive axons and terminals were found throughout the brain. These observations extend our earlier work on VGF expression in the hypothalamus to other regions of the brain and support the conclusion that although VGF expression is only detected in subsets of neurons in each brain region, these subsets are widely distributed throughout the central nervous system. © 1994 Wiley‐Liss, Inc.
Structure and function of gustatory neurons in the nucleus of the solitary tract. I. A classification of neurons based on morphological features
Authors: Renehan William E. , Jin Zhigao , Zhang Xueguo , Schweitzer Laura
Published: January 2005

Prior investigations in other laboratories have provided convincing evidence that the neurons of the rostral nucleus of the solitary tract (rNST) can be grouped according to their physiological response properties or morphologic features. The present study is based on the premise that the response properties of gustatory neurons are related to, and perhaps governed by, their morphology and, connectivity. In this first phase of our ongoing investigation of structure‐function relationships in the rNST of the rat, we have used intracellular injection of neurobiotin to label individual physiologically characterized gustatory neurons. A total of 63 taste‐sensitive neurons were successfully labeled and subjected to three‐dimensional quantitative and qualitative analysis. A cluster analysis using six morphologic features (total cell volume, soma area, mean segment length, swelling density, spine density, and number of primary dendrites) was used to identify six cell groups. Subsequent analyses of variance and posthoc comparisons verified that each of these six groups differed from all others with respect to at least one variable, so each group was “typified” by at least one of the six morphologic features. Neurons in group A were found to be the smallest neurons in the sample. The cells in group B had small somata and exhibited the highest swelling density of any group. Group C neurons were distinguished by dendrites with long, spine‐free branches. These dendrites were significantly longer than those of any other group except Group F. The neurons in group D had more primary dendrites; than any other group. Group E neurons possessed dendrites with the lowest swelling density but the most spines of any group. The cells in group F were the largest neurons in our sample and possessed the largest somata of any group. Thus, overall cell size and density of dendritic spines and swellings were found to be particularly important variables in this classification scheme. Our preliminary results suggest that the number and density of dendritic spines (as well as other morphologic features) may be related to a given neuron's most effective stimulus, indicating that it will indeed be possible to use the criteria established in the present investigation to derive structure‐function relationships for gustatory neurons in the rNST. © 1994 Wiley‐Liss, Inc.
Hypoxia and electrical stimulation of the carotid sinus nerve induce fos‐like immunoreactivity within catecholaminergic and serotoninergic neurons of the rat brainstem
Authors: Erickson Jeffery T. , Millhorn David E.
Published: January 2005

A complete understanding of the neural mechanisms responsible for the chemoreceptor and baroreceptor reflexes requires precise knowledge of the locations and chemical phenotypes of higher‐order neurons within these reflex pathways. In the present study, the protein product (Fos) of the c‐fos protooncogene was used as a metabolic marker to trace central neural pathways following activation of carotid sinus nerve afferent fibers. In addition, immunohistochemical double‐labeling techniques were used to define the chemical phenotypes of activated neurons. Both electrical stimulation of the carotid sinus nerve and physiological stimulation of the carotid bodies by hypoxia induced Fos‐like immunoreactivity in catecholaminergic neurons containing tyrosine hydroxylase or phenylethanolamine‐N‐methyltransferase in the ventrolateral medulla oblongata and, to a lesser degree, in the dorsal vagal complex. Tyrosine hydroxylase/Fos colocalization was also observed in the locus coeruleus and the A5 noradrenergic cell group in pons. Many serotoninergic neurons in nucleus raphe pallidus, nucleus raphe magnus, and along the ventral medullary surface contained Fos‐like immunoreadtivity. In pons and midbrain, Fos‐like immunoreactivity was observed in the lateral parabrachial and Kölliker–Fuse nuclei, the inferior colliculus, the cuneiform nucleus, and in the vicinity of the Edinger–Westphal nucleus, but no catecholaminergic or serotoninergic colocalization was observed in these regions. Although Fos‐labeled cells were observed within and lateral to the dorsal raphe nucleus, few were catecholaminergic or serotoninergic. This study further defines a potential central neuroanatomical substrate for the chemoreceptor and/or baroreceptor reflexes. © 1994 Wiley‐Liss, Inc.
Development of microglia in the quail optic tectum
Authors: Cuadros Miguel A. , Moujahid Amale , Quesada Antonio , Navascués Julio
Published: January 2005

The development of microglia in the quail optic tectum from embryonic day 6 to adulthood was studied by using the QH1 monoclonal antibody. In youngest tecta, microglial cells were scarcely present, but their number rose in subsequent stages. A clear pattern of microglial cell distribution was observable in embryos of 9–16 days. (1) Round cells appeared close to the ventricular layer. (2) Large numbers of ameboid and round labeled cells were seen in the stratum album centrale during development. A gradient of cell density was observable in this layer, as fewer labeled cells appeared in medial regions of the tectum than in lateral regions. (3) Maturing ramified cells were found in layers external to the stratum album centrale, where they increased in number and in branching complexity during development. In adult tecta, almost all microglial cells were of the mature ramified type and were distributed homogeneously in the different tectal layers, although in some layers they had particular morphological features.

The distribution of microglia in the developing tectum and in adjacent regions provided insight into the routes of microglial cell invasion of the tectum during development. Apparently, a proportion of microglial cells reached the tectal parenchyma from the meninges and from the ventricular lumen, but the majority of them migrated along nerve fiber tracts from their entry point at the pial surface of the ventromedial caudal tectum. After they reached the stratum album centrale, microglial cells continued their migration toward more external layers, where they differentiated into ramified microglia. © 1994 Wiley‐Liss, Inc.
Galanin immunoreactivity in autonomic innervation of the cat eye
Authors: Grimes Patricia A. , McGlinn Alice M. , Koeberlein Brigitte , Stone Richard A.
Published: January 2005

In an immunohistochemical study, we find that galanin is much more widely distributed in the peripheral innervation of the cat eye than in other animals so far examined. Previous studies of rat and pig eyes have revealed sparse galanin‐positive nerves that presumbably originate in the trigeminal ganglion. In contrast, the cat has a rich supply of galanin‐containing nerve fibers throughout the uvea. Galanin‐positive varicose nerves concentrate densely in iris muscles and distribute more sparsely in the ciliary muscle. The ciliary processes have a plexus of galanin‐positive nerve underlying the ciliary epithelium at their base and positive nerve fibers coursing within their stroma. The ciliary artery and its branch vessels in the uvea are invested with a dense plexus of galanin‐positive nerves. All autonomic ganglia supplying the eye contain cells that express galanin. It is present in 97% of superior cervical ganglion cells, coexisting with both tyrosine hydroxylase and neuropeptide Y; in 80% of pterygopalatine ganglion cells, most of whiclh also contain vasoactive intestinal peptide; and in approximately 25% of ciliary ganglion celis. After unilateral superior cervical ganglionectoiny, galanin‐positive nerves almost totally disappear from the iris muscles, demonstrating that they are predominantly of sympathetic origin. Galanin‐positive nerves investing the ciliary artery and choroidal blood vessels are not detectably reduced by sympathectomy, indicating that perivascular parasympathetic nerves from the pterygopalatine ganglion also express galanin. Other galanin‐containing nerves in the eye can originate from the trigeminal and ciliary ganglia. The prominence of galanin in the ocular autonomic innervation of the cat provides an opportunity to explore the physiological effects of this neuropeptide in the eye. © 1994 Wiley‐Liss, Inc.
Patterning of the neocortical projections from the raphe nuclei in perinatal rats: Investigation of potential organizational mechanisms
Authors: Bennett‐clarke Carol A. , Hankin Mark H. , Leslie Michael J. , Chiaia Nicolas L. , Rhoades Robert W.
Published: January 2005

Serotoninergic (5‐HT), fibers in the cerebral cortex of perinatal rats have a pattern that coincides with the boundaries of primary sensory areas and within the primary somatosensorycortex form the rattunculus. This patterned immunoreactivity (IR) appears about 60 hours after birth and disappears between postnatal days (P‐) 12 and 15. Three experiments were carried out to evaluate mechanisms that might underlie the precise patterning of the 5‐HT‐IR. Retrograde labelling with fluorescent tracers in perinatal rats revealed only a coarse rostrocaudal to ography in the raphe‐cortical projection and the existence of raphe cells projecting to multiple cortical locations. Thus, a precise point‐to‐point, raphe‐cortical projection does not underlie the patterned cortical 5‐HT‐IR.

Ablation of the thalamus prior to the age at which patterned 5‐HT‐IR could be seen in the developing cortex caused a complete loss of patterned immunoreactivity. This suggests that 5‐HT fibers may require the presence of thalamocortical axons to achieve the pattern observed in normal animals.

Serotoninergic raphe neurons transplanted to the cortices of newborn rats exhiwited extensive axonal outgrowth, but did not form a somatotopic pattern. This result also suggests that specific spatiotemporal interactions between growing 5‐HT and thalamocortical axons may be necessary for the somatotopic patterning of the former fibers. © 1994 Wiley‐Liss, Inc.
TRK‐immunoreactivity in the monkey central nervous system: Forebrain
Authors: Kordower Jeffrey H. , Chen Er‐Yun , Sladek John R. , Mufson Elliott J.
Published: January 2005

Neurotrophins such as nerve growth factor (NGF) mediate their effects through interactions with high‐affinity tropomycin‐related kinase (trk) receptors. The present study employed a polyclonal antibody to characterize the distribution of trk‐immunoreactive neurons within the nonhuman primate brain. Both young adult and aged cebus and rhesus monkeys displayed trk‐immunoreactive neurons within all subdivisions of the basal forebrain. Colocalization studies revealed that between 66% and 76% of trk‐immunoreactive basal forebrain neurons also expressed immunoreactivity for the low‐affinity p75 NGF receptor, an excellent marker for cholinergic basal forebrain cells. In this experiment, most single‐labeled basal forebrain neurons contained only trk immunoreactivity, whereas 4% of basal forebrain neurons expressed only the low‐affinity p75 NGF receptor. Scattered trk‐immunoreactive neurons also were observed within the caudate nucleus and putamen. Although dual‐localization studies with choline acetyltransferase (ChAT) were not performed, striatal neurons codistributed with ChAT‐immunoreactive cells, and both types of cells were similar in size and morphology. This suggests that trk immunoreactivity is expressed within cholinergic interneurons within the primate striatum. Finally, lightly stained trk‐immunoreactive neurons were observed within the stratum oriens of the hippocampal formation and within the hypothalamus. These data indicate that both cholinergic and, possibly, noncholinergic forebrain neurons express the protein for the high‐affinity trk receptor, which transduces the signal mediating the trophic effects of neurotrophins. In addition, the pattern of trk immunoreactivity was preserved in two aged (26 and 29 years old) rhesus monkeys, suggesting that the expression of trk, for the most part, is sustained throughout the lifetime of the organism. © 1994 Wiley‐Liss, Inc.
Postnatal development of [D‐Ala2]deltorphin‐I‐like immunoreactive structures in the rat brain
Authors: Nonomura Kazuo , Tooyama Ikuo , Abe Hiromichi , Renda Tindaro , Erspamer Vittorio , Shimada Morimi , Kimura Hiroshi
Published: January 2005

[D‐Ala2]deltorphin‐I, a highly selective ligand for δ opioid receptors, is a heptapeptide originally purified from frog skin. Previous immunohistochemical studies indicate that [D‐Ala2]deltorphin‐I‐like molecule(s) may be present in adult rat brain, including specific neuronal cells and fibers partially overlapping with the mesocortical and nigrostriatal dopaminergic systems. Here, we examined the developmental aspect of such immunoreactive brain structures in early postnatal rats. In newborn to 21‐day‐old rats, positive staining in the brain occurred mainly in subpopulations of neurons and occasionally in tanycytes. On postnatal day 0, neuronal cell bodies containing [D‐Ala2]deltorphin‐I‐like immunoreactivity were found in various brain regions, including the olfactory tubercle, ventral pallidum, hippocampus, ventral tegmental area, pars compacta of the substantia nigra, supramammillary nucleus, and dorsal raphe nucleus. Immunoreactive nerve fibers were observed in the main and accessory olfactory bulbs, olfactory tubercle, prelimbic area, anterior cingulate cortex, neostriatum, accumbens, lateral septal nucleus, lateral habenular nucleus, and superior colliculus. As pups grew, positive staining of cell bodies decreased gradually in both density and intesity, and those in the olfactory tubercle and ventral pallidum were no longer visible on postnatal day 14. On postnatal day 21, positive cells were found only in the ventral midbrain, including the pars compacta of the substantia nigra, ventral tegmental area, A8 region, and supramammillary nucleus. Positive fibers also decreased in density with age except in the accessory olfactory bulb, olfactory tubercle, prelimbic area, and anterior cingulate cortex. © 1994 Wiley‐Liss, Inc.
Hearing, vocalization and the external ear of a marsupial, the Northern Quoll, Dasyurus hallucatus
Authors: Aitkin L. M. , Nelson J. E. , Shepherd R. K.
Published: January 2005

As part of a continuing study of the development of the marsupial auditory system, auditory brainstem responses (ABR) were recorded and an ABR audiogram was constructed for five female Northern Quolls (Dasyurus hallucatus), which are nocturnal carnivores. The best frequency for hearing lies between 8 and 10 kHz, and at 50 dB SPL there is a range from about 0.5 to 40 kHz.

Vocalizations of adult quolls and pouch‐young were recorded with a digital audio tape recorder, and the power spectra of representative calls were compared with the ABR audiogram. The common adult vocalization have most energy at the lower end of the hearing range, whereas frequencies that are dominant in the isolation calls of the pouch‐young lie close to the best frequency of hearing.

Samples of nocturnal sounds of the habitat of the quoll were also recorded and analyzed. Power spectra have peak energy at frequencies between 2 and 5 kHz, with a smaller contribution above 10 kHz. The spectrum contains relatively little power at the best frequency of hearing.

Measurements of the sound pressure level at the external ear canal as a function of stimulus frequency and location in space suggest that the directional amplifying properties of the pinna will operate most effectively on sound frequencies at the upper end of the quoll's hearing range, a region that may be important in prey detection.

Comparisons are made with other mammalian nocturnal carnivores and with other marsupials. We speculate that, for nocturnal carnivores, one role of the low‐frequency part of the hearing range concerns the recognition of adult conspecifics, the mid‐frequency range is important for the detection of pouch‐young, and the upper range may be particularly concerned with prey/predator detect on. © 1994 Wiley‐Liss, Inc.
Neuroarchitecture of the tritocerebrum of Drosophila melanogaster
Authors: Rajashekhar K. P. , Singh R. Naresh
Published: January 2005

The organisation of the tritocerebrum of Drosophila melanogaster was studied by Bodian‐Protargol reduced silver staining, Golgi‐silver impregnation, horseradish peroxidase (HRP), and cobalt‐chloride labelling of neurones and transmission electron microscopy. Nerve fibres of six categories were found to project to the tritocerebrum. (1 and 2) The sensory fibres from the internal mouthpart sensilla known to course along pharyngeal and accessory pharyngeal nerves were found to project in mainly two tiers, in the tritocerebrum. (3) Stomodaeal nerve fibres also project along the pharyngeal nerve, to the tritocerebrum. (4) Cells of the pars intercerebralis (PI) project along the median bundle and arborise in the tritocerebrum. HRP labelling and subsequent examination by transmission electron microscopy indicated their neurosecretory nature. (5 and 6) Two tracts of ascending fibres, designated as dorsal and ventral ascending tracts, were found to project to the tritocerebrum.

Some of the sensory fibres from the labial nerve extend close to the sensory projections of the tritocerebrum, suggesting a possible convergence of the two sensory inputs. In the tritocerebrum, the sensory input, the stomodaeal input, the neurosecretory fibres of PI, and the ascending fibres were found to have overlapping fields, suggesting mutual interaction. The medial subesophageal ganglion and the tritocerebrum may interact through the ventral ascending tract. © 1994 Wiley‐Liss, Inc.
Distribution of messenger RNAs encoding enkephalin, substance P, somatostatin, galanin, vasoactive intestinal polypeptide, neuropeptide Y, and calcitonin gene‐related peptide in the midbrain periaqueductal grey in the rat
Authors: Smith Guy S. T. , Savery Dawn , Marden Chloë , Costa Juan Jose López , Averill Sharon , Priestley John V. , Rattray Marcus
Published: January 2005

The midbrain periaqueductal grey matter (PAG) has numerous functional roles that include mediating nociceptive inhibition and integrating behavioural and physiological responses to potentially threatening or stressful stimuli. Underlying these behaviours is the diverse interconnectivity of this region, and it is possible that neurochemical subdivisions within the PAG reflect the functional properties of the different PAG regions. In this study, using in situ hybridization, we have investigated the distribution in the rat PAG of the messenger ribonucleic acids (mRNAs) encoding seven neuropeptides: enkephalin (ENK), substance P (SP), somatostatin (SST), galanin (GAL), vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), and calcitonin gene‐related peptide (CGRP). Each peptide mRNA had a distinct topographical distribution in the PAG. Preproenkephalin A (ENK) mRNA‐expressing cells were found at all levels of the PAG in three distinct longitudinal columns. Preprotachykinin A (SP)‐expressing cells were found at all levels of the PAG, principally in the Edinger‐Westphal nucleus and the lateral and dorsal PAG. There was a column of neurones producing mRNA‐encoding somatostatin that extended along the rostrocaudal extent of the ventrolateral PAG; there were also labelled cells in the dorsal and dorsolateral subdivisions at some levels of the PAG. Galanin mRNA‐producing neurones were limited to the dorsal raphe nucleus and to a second population in the ventral border of the aqueduct. VIP mRNA‐producing neurones were found in very localized regions of the PAG, including the cell‐sparse region immediately ventral to the aqueduct and the ventral part of the dorsal raphe nucleus. NPY mRNA‐producing neurones were localized mainly in some cells of the Edinger‐Westphal nucleus and dorsal raphe nucleus. CGRP mRNA‐expressing neurones were limited to the oculomotor and trochlear nucleus. The results showed a topographical distribution of neuropeptides over the rostrocaudal extent of the PAG that is compatible with the emerging theory that the anatomical and functional specificity of the PAG is expressed in the form of longitudinally arranged neuronal columns that extend for varying distances along the rostrocaudal axis of the midbrain PAG. © 1994 Wiley‐Liss, Inc.
Timecourse of development of the wallaby trigeminal pathway. I. Periphery to brainstem
Authors: Waite P. M. E. , Marotte L. R. , Leamey C. A.
Published: January 2005

The development of the vibrissae and their innervation and the maturation of the brainstem trigeminal sensory nuclei have been studied in the wallaby, Macropus eugenii, from birth to adulthood. At birth, developing vibrissal follicles consist of solid epidermal pegs surrounded by dermal condensations. The developing follicles and adjacent skin are innervated by trigeminal afferents. Ten days after birth the follicle contains a dermal papilla and the deep vibrissal nerve can be recognised. A hair cone is present at postnatal day (P) 30 and hairs are apparent on the skin surface by P35. By P63 the deep vibrissal nerve can be seen innervating Merkel cells in the outer root sheath; in addition, the first signs of the blood sinus can be recognised. Innervation of the inner conical body and lanceolate and lamellated receptors supplying the mesenchymal sheath and waist region are not seen until P119, when the follicle resembles that seen in the adult.

At birth, central processes of the trigeminal ganglion cells have entered the trigeminal tract and extend from the rostral pons to the upper cervical cord. Labelling with a carbocyanine dye at P0 shows afferents extending medially from the tract into the trigeminal subnuclei at all levels. At this stage the trigeminal nuclei appear as areas of increased cell density in the lateral brainstem. By P30–40 the four subnuclei can be distinguished on the basis of shape, cytoarchitecture, and succinic dehydrogenase reactivity. Adult morphology is not fully established until P210. In mature animals, nucleus principalis contains closely packed, polymorphic cells, frequently aligned parallel to thick fibre bundles that traverse the nucleus obliquely. Subnuclei oralis and interpolaris contain sparsely distributed, medium to large cells, randomly oriented, as well as prominent rostrocaudally directed fibre bundles. Subnucleus caudalis consists of the marginal layer, substantia gelatinosa, and magnocellular layers as described in other species.

Patches of increased succinic dehydrogenase or cytochrome oxidase reactivity, presumably corresponding to the vibrissae, are present in subnuclei principalis, interpolaris, and caudalis in developing and adult animals, although the pattern is less clear than in rats. The brainstem patches are first seen at P40, approximately 6 weeks before the corresponding vibrissal‐related pattern develops in the cortex. This suggests that the onset of patch formation may be regulated independently at different levels of the pathway. © 1994 Wiley‐Liss, Inc.
Vitread proliferation of filamentous processes in avian Müller cells and its putative functional correlates
Authors: Dreher Zofia , Distler Claudia , Dreher Bogdan
Published: January 2005

In order to examine to what extent the neuronal and metabolic activities of avascular vertebrate retinae are reflected in the morphology of their Müller cells we have studied (by using several monoclonal antibodies) the morphology of Müller cells in two species of diurnal birds (chicken, Gallus domesticus, and pigeon, Columba livia) and one species of nocturnal saltwater crocodiles (Crocodylus porosi). In all three species, the outer nuclear layer is relatively thin and the Müller cell trunks divide into rootlets that wrap around the photoreceptors. In both diurnal birds studied, the trunks of Müller cells in the inner plexiform layers invariably divide into numerous fine filamentous processes that terminate in small expansions covering most of the vitreal surface of the retina. Furthermore, the networks of filamentous processes of birds' Müller cells exhibit conspicuous horizontal lamination in the inner plexiform layer. In contrast, the filamentous processes arising from the individual Müller cell trunks of the crocodile, if present, are much less numerous and less widely spread than those of diurnal birds. It is proposed that the splitting of the Müller cell trunks into numerous filamentous processes terminating in small vitreal expansions represents a morphological adaptation for: (1) effective spatial buffering of K+ ions in thick and presumably metabolically highly active, yet avascular, avian retinae, and (2) effective absorption and distribution of nutrients leaking from the vitreally located supplemental nutritive organ, the pecten. © 1994 Wiley‐Liss, Inc.