bluuebunny/crossref_metadata_2025_split huggingface dataset:
Region‐specific distribution of catecholamine afferents in primate cerebral cortex: A fluorescence histochemical analysis
Authors: Levitt Pat , Rakic Pasko , Goldman‐Rakic Patricia 
Published: January 2005

AbstractThe density, laminar distribution, spatial orientation, and intrahemispheric pathways of norepinephrine (NE)‐ and dopamine (DA)‐ containing axons were analyzed in a wide range of cytoarchitectonically distinct areas of cerebral cortex in the adult rhesus monkey by fluorescence histochemistry. Although the boundaries between most areas were rarely sharp, there were marked regional differences in density and distribution of monoamine afferents in different cortical regions. Fibers exhibiting typical DA‐like morphology were found only in the temporal and frontal lobes including motor and premotor areas as well as anterior cingulate and prefrontal cortices. In contrast, NE‐containing axons were present in all cerebral lobes, with notably high density in the somatosensory area and low numbers in primary visual cortex. Intracerebral distribution was characterized by a network of large preterminal axons coursing both anteroposteriorly and mediolaterally in layer VI and in the subjacent white matter. In most cytoarchitectonic regions examined, catecholamine (CA)‐containing axons exhibited a bilaminar distribution into one superficial and one deep fiber band. The location and width of the two dense bands, as well as the orientation and relative density of fibers within them, was region specific. Although fluorescent axons were found at all cortical depths, layers I, and IV usually contained relatively few fluorescent axons while layers II–III and IV–V were often densely innervated. An observation that may reflect a specialization in gyrencephalic brains is the particularly dense CA innervation around sulcal invaginations in all cerebral lobes. The present results confirm previous biochemical evidence of regional heterogeneity in the concentration of DA and NE in the primate neocortex (Brown and Goldman, '77; Brain Res. 124:576–550) and provide the first anatomical demonstration of corresponding differences in the pattern and density of CA innervation in diverse cytoarchitectonic areas in rhesus monkey. These findings raise the possibility of seletive targets and functions for CA fibers in different layers and regions of the primate cortex.
Ultrastructural localization of tyrosine hydroxylase in rat nucleus accumbens
Authors: Bouyer J. J. , Joh T. H. , Pickel V. M. 
Published: January 2005

AbstractImmunocytochemical localization of tyrosine hydroxylase (TH) was used to determine the ultrastructural morphology and synaptic associations of catecholaminergic terminals in the nucleus accumbens of the rat. The brains were fixed by vascular perfusion with 4% paraformaldehyde and 0.2% glutaraldehyde. Coronal sections cut with a vibrating microtome were incubated with rabbit antiserum to TH then immunocytochemically labeled by the peroxidase‐antiperoxidase method. Immunoreactivity for the enzyme was found within unmyelinated axons and axon terminals. These terminals contained either all small clear or combined small clear and large dense core vesicles. Approximately 40% of the labeled terminals formed symmetric synapses with unlabeled proximal or distal dendritic shafts. The dendrites showed a sparse distribution of spines. Axosomatic synapses and axonal associations of the TH‐containing terminals also were detected. The recipient perikarya were usually 10–20 μm in diameter and contained an indented nucleus and abundant cytoplasm. The content of large dense vesicles and synaptic associations with somata and proximal dendrites suggest that a certain proportion of the TH‐containing terminals within the nucleus accumbens are morphologically distinct from catecholaminergic terminals within the dorsal striatum. These differences are discussed in relation to neuropeptides and functions of the dopaminergic mesolimbic and nigrostriatal pathways.
The effects of capsaicin applied to peripheral nerves on responses of a group of lamina I cells in adult rats
Authors: McMahon S. B. , Wall P. D. , Granum S. L. , Webster K. E. 
Published: January 2005

AbstractIn adult rats, the sciatic and saphenous nerves on one side were treated topically with capsaicin. The capsaicin treatment had the effect of increasing the latency for withdrawal of the foot from hot water; 11–22 days later, the animals were decerebrated, and cells in the superficial dorsal horn of the lumbar cord with axons projecting in the contralateral dorsolateral funiculus (DLF) were examined electrophysiologically on the treated and untreated sides of the cord. HRP was applied to cut axons of the DLF at C4, in other rats, and retrograde labelling of cells in the lumbar cord indicated that most or all of the recordings in the capsaicin‐treated animals were likely to originate from lamina 1. The dorsal horn cells, with receptive fields on the foot, showed decreased responses to electrically evoked afferent impulses in C fibres and grossly altered receptive fields.After capsaicin treatment, the proportion of cells responding to C afferents fell from 83% to 14%. The proportion responding only to C afferents and not to A afferents fell from 9% to 0%.The receptive fields (RFs) of these cells showed two gross abnormalities; 32% of the cells on the treated side had no apparent RF or an ill‐defined, intermittent RF, whereas such cells were rare on the untreated side or in intact animals. By contrast 49% of the cells had grossly expanded RFs with an average area of 430 mm2 against the normal average size of 130 mm2.The antidromic conduction velocity of the axons of the cells was measured, and while there was no significant change in the number of cells with axons conducting above 3 m/second, an increased number of cells with lower velocities were recorded. It is suggested that the capsaicin treatment induced dendritic changes in cells with small axons allowing antidromic spikes to invade these cells.
Selective loss of neurites during differentiation of cells in the leech central nervous system
Authors: Wallace Bruce G. 
Published: January 2005

AbstractThe arborizations of annulus erector (AE) motoneurons in the central nervous system of the leech, Hirudo medicinalis, have been examined during embryogenesis to determine how segmental differences in their branching patterns arise. Early in development AE motoneurons all along the ganglionic chain had a similar central arborization, with major branches extending both rostrally and caudally along the connectives that link adjacent ganglia. As the embryo grew, the processes in the connectives elongated but failed to increase significantly in caliber and eventually atrophied and were lost. This sequence of events did not occur uniformly along the cord, however. AE motoneurons in midbody ganglia lost both anterior and posterior branches, cells near the head lost only their posterior branch, while cells near the tail lost only their anterior branch. In this way, the selective atrophy of neurites during development produced a systematic segmental difference in the morphology of homologous cells.
Further studies of the secretory process in hypothalamo‐neurohypophysial neurons: An analysis using immunocytochemistry, wheat germ agglutinin‐peroxidase, and native peroxidase
Authors: Broadwell Richard D. , Cataldo Anne M. , Balin Brian J. 
Published: January 2005

AbstractThe axonal endoplasmic reticulum (ER) and synaptic‐like (micro)vesicles within axon terminals of the neurohypophysis and their contribution to the secretory process in hypothalamo‐neurohypophysial neurons have been investigated cytochemically in normal mice and in mice given 2% salt water to drink for stimulation of hormone synthesis in and release from these neurons. Cytochemical techniques included the peroxidase‐antiperoxidase (PAP) immunocytochemical method for localization of neurophysin, wheat germ agglutinin‐horseradish peroxidase (WGA‐HRP) as a tracer for the anterograde axonal transport of membrane from within the perikaryon, and blood‐borne native horseradish peroxidase (HRP) as a tracer for internalized axon terminal membrane. The primary antiserum employed was directed against neurophysins I and II, the carrier proteins for the peptide hormones oxytocin and vasopressin, respectively. PAP reaction product was observed over neurosecretory granules but never over the endoplasmic reticulum, microvesicles or other organelles in axons and terminals of the neurohypophysis WGA‐HRP was delivered extracellularly to cell bodies of paraventricular neurons by cerebral ventriculocisternal perfusion. Internalized perikaryal surface membrane tagged with WGA‐HRP was recycled through the innermost Golgi saccule (GERL) from which neurosecretory granules were formed. The anterograde axonal transport of membrane‐bound WGA‐HRP was manifested within the neurosecretory granules; WGA‐HRP did not label the axonal reticulum or terminal microvesicles in the neurohypophysis. Blood‐borne native HRP endocytosed into neurohypophysial terminals was associated with a plethora of microvesicles measuring 40–70 nm in diameter and vacuoles similar in size to the 100–300‐nm‐wide neurosecretory granules. The microvesicles contributed to the formation of numerous vacuoles. The internalization of axon terminal membrane as microvesicles incorporating HRP was quantitatively greater than vacuoles in both salt‐stressed and control mice. The results suggest that in the hypothalamo‐neurohypophysial system of the mouse the axonal ER and terminal microvesicles are not involved in the transport, storage, and exocytosis of neurosecretory material and perhaps other molecules processed through the innermost Golgi saccule. Nevertheless, a prominent population of the microvesicles within axon terminals of the neurohypophysis does participate in the secretory process. These vesicles are involved directly in the internalization of the terminal surface membrane subsequent to release of secretory granule content. The recapture of neurohypophysial terminal membrane in toto may be represented as endocytic structures ranging in size from 40 through 300 nm in diameter.
Rostral ventrolateral medulla: Selective projections to the thoracic autonomic cell column from the region containing C1 adrenaline neurons
Authors: Ross Christopher A. , Ruggiero David A. , Joh Tong H. , Park Dong H. , Reis Donald J. 
Published: January 2005

AbstractAnterograde, retrograde, and combined axonal transport methods were used to describe the descending efferent projections of a region of rostral ventrolateral medullary reticular formation important in cardiovascular control. We have termed this region, which contains C1 adrenaline‐synthesizing neurons, the nucleus reticularis rostroventrolateralis (RVL).Efferent projections from the RVL innervate all segmental levels of the thoracic intermediolateral and intermediomedial columns as shown using retrograde transport of lectin‐conjugated horseradish peroxidase (HRP) or fast blue dye, and anterograde transport of either HRP or labeled amino acids. The projection is highly specific in that there are no projections to thoracic dorsal or ventral horns. This innervation corresponds to the distribution of preganglionic sympathetic neurons in the intermediolateral column. In particular, terminals surround neurons projecting to the adrenal medulla, as demonstrated by combined anterograde and retrograde transport methods at the light level.Terminals containing phenylethanolamine‐N‐methyl transferase (PNMT) were mapped using immunocytochemical techniques. PNMT‐labeled terminals were present at all levels of thoracic intermediolateral column, in a distribution similar to that of the descending projections from the RVL. We have previously shown using double label techniques (Ross et al, '81–'83), that many of the spinal projections of the RVL originate from C1 neurons.These data support our suggestion that certain bulbospinal neurons within the RVL, in particular the C1 neurons, are crucial for tonic vasomotor control.
Cortical projections to nuclei adjacent to oculomotor complex in the medial dien‐mesencephalic tegmentum in the monkey
Authors: Leichnetz G. R. , Spencer R. F. , Smith D. J. 
Published: January 2005

AbstractCortical projections to cell groups surrounding the oculomotor complex were studied by using the retrograde and anterograde capabilities of the horseradish peroxidase (HRP) technique in old and new world monkeys. Fluid HRP injections or transcannular solid polyacrylamide HRP gel implants were made into the oculomotor nucleus (OMN) and adjacent nuclei to label retrogradely corticofugal neurons that project to this region, and cortical HRP gel implants were made in various areas of the frontal lobe to label anterogradely the trajectories and terminations of cortico‐paraoculomotor projections and thus to confirm the retrograde findings. Projections to the paraoculomotor cell groups in the medial dien‐mesencephalic tegmentum originate almost exclusively from the frontal lobe. Both retrograde and anterograde studies confirmed that the prearcuate cortex in the concavity of the arcuate sulcus, including the frontal eye field, and, to a lesser extent, suprarcuate rostral dorsal area 6 cortex and the dorsomedial convexity (area 9), project to the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF) in the dorsal region of the prerubral field, nucleus of Darkschewitsch (ND), medial accessory nucleus of Bechterew (NB) and dorsomedial parvocellular red nucleus (dmPRN). The premotor area 6 and motor area 4 cortex, on the other hand, give rise to projections that target a larger portion of the parvocellular red nucleus, extending rostrally into the ventral region of the prerubral field, and a rather intense projection to the ND. The interstitial nucleus of Cajal (IC) was distinguished more by its light, or lack of, projections from the frontal cortex. The inferior parietal lobule (IPL, area 7) which has certain common physiological properties with the frontal eye field (FEF area 8) related to the oculomotor system, lacked retrogradely labeled neurons in all cases where transcannular gel implants into the OMN eliminated the possibility of HRP uptake in the corpus callosum or other structures traversed in needle injections, suggesting that the IPL affects eye movement primarily through its rostrally directed corticocortical associational connections with the FEF. In additional cases, the NDNB‐dmPRN configuration of cells that receives FEF input is shown to project to the inferior olivary complex (i.e., is pre‐olivo‐cerebellar), whereas riMLF and IC give rise to descending projections in the MLF, which target extraocular muscle motor nuclei, vestibular complex, and spinal cord. The results are discussed in terms of the potential role of the cerebral cortex in eye movement mechanisms.
Thalamocortical and other synapses involving nonspiny multipolar cells of mouse SmI cortex
Authors: White Edward L. , Benshalom Gadi , Hersch Steven M. 
Published: January 2005

AbstractGolgi‐impregnated and ‐deimpregnated neurons having somata in layer IV of mouse posteromedial barrel subfield (PMBSF) cortex were identified with the light microscope and then extensive portions of them were examined with the electron microscope. Dendrites of nine nonspiny multipolar cells and eight of their cell bodies were reconstructed from serial thin sections to determine the numbers and types of symmetrical, asymmetrical, and thalamocortical synapses they formed. Results of this analysis show that cells of the same general morphological class may form widely different patterns of synaptic connections: some nonspiny multipolar cells had dendrites that formed a high proportion of their synapses with thalamocortical axon terminals, whereas dendrites belonging to other cells formed only very small proportions of thalamocortical synapses. A similar diversity characterized the synaptic connections of cell bodies: some formed more symmetrical than asymmetrical synapses, others the reverse. Some formed high proportions of thalamocortical synapses, others much less. Comparisons of thalamocortical synaptic input to cell bodies and dendrites showed that one cell formed about the same proportions of thalamocortical synapses with its cell body as with its dendrites. For two other cells the proportions of thalamocortical synapses formed with their somata was about double that formed with their dendrites. The remaining five cell bodies examined formed far higher proportions of thalamocortical synapses than did their dendrites. That different nonspiny multipolar cells form such contrasting synaptic patterns suggests that included within this morphological classification are cells which are likely to have very different functional roles.
A comparison of the ultrastructure of substance P and enkephalin‐immunoreactive elements in the nucleus of the dorsal lateral funiculus and laminae I and II of the rat spinal cord
Authors: Bresnahan Jacqueline C. , Ho Raymond H. , Beattie Michael S. 
Published: January 2005

AbstractThe ultrastructure of substance P (SP)‐ and enkephalin (ENK)‐immunoreactive elements in the nucleus of the dorsal lateral funiculus (NDLF) and in laminae I and II of the spinal cord was examined in the rat using the peroxidate‐antiperoxidase (PAP) technique. Electron‐microscopic observations were made of a large number of immunolabelled terminals (n = 428; many followed in serial sections), axons, and immunoreactive cell bodies and dendrites which were occasionally encountered. Morphometric analysis was used to describe and compare the fine structural features of immunolabelled elements. Both SP‐ and ENK‐immunoreactive terminals contained clear synaptic vesicles and dense‐cored vesicles of similar size but the ENK‐immunoreactive profiles contained significantly more dense‐cored vesicles than SP‐immunolabelled profiles. Both SP‐ and ENK‐immunoreactive profiles in the dorsal laminae of the dorsal horn contacted mainly smaller dendritic elements. Only rarely were axo‐axonic interactions noted. The NDLF contains widely scattered cell bodies dispersed within a neuropil which is rich in synaptic complexes and is interdigitated between fascicles of myelinated and unmyelinated axons. Numerous SP‐ and ENK‐immunoreactive profiles were observed in the NDLF, many of which made asymmetric synaptic contacts with NDLF neurons. Although both the dorsal gray and NDLF contain large numbers of SP‐ and ENK‐immunoreactive elements which are similar in morphology in both regions, the NDLF can be distinguished from laminae I and II by a number of criteria, including the nature of the neuropil, principle sources of SP innervation, and the termination patterns of ascending projections.
Midbrain tegmental projections of nucleus reticularis thalami of cat and monkey: A retrograde transport and antidromic invasion study
Authors: Parent A. , Steriade M. 
Published: January 2005

AbstractThe projections of reticularis thalami (RE) neurons to midbrain reticular formation (MRF) and superior colliculus (SC) were studied in cat and monkey by using retrograde transport techniques and antidromic identification. The projections to MRF arise in rostral parts and lateral extent of RE nuclear complex whereas RE fibers to SC predominantly originate in the RE poster‐oventral district, Following injections of horseradish peroxidase (HRP) or fluorescent tracers into the MRF territory, retrogradely labeled neurons were always more numerous in the lateral hypothalamus and zona incerta than in the continuing RE wing. There were only very few doubly labeled RE cells following injections of fluorescent tracers into the midbrain tegmentum and thalamic nuclei, despite the fact that numerous doubly labeled cells occurred in the internal part of globus pallidum and pars reticulata of substantia nigra in the same animals. Control injections in the pons showed that RE labeling after midbrain injections was not due to uptake by fibers coursing more caudally. Antidromic identification experiments in cat confirmed the existence of a descending RE input to midbrain and further indicated that RE‐midbrain projections consist of slow‐conducting (≏1 m/second) axons.
Projections from C2 and C3 nerves supplying muscles and skin of the cat neck: A study using transganglionic transport of horseradish peroxidase
Authors: Abrahams V. C. , Richmond F. J. , Keane J. 
Published: January 2005

AbstractTransganglionic transport of HRP has been used to trace the pathways and termination sites of cutaneous and muscle afferent axons entering from the C2 and C3 dorsal rami. The muscle afferent projection in the spinal cord is restricted and (apart from the ventral horn) largely confined to the intermediate gray matter. There is a muscle afferent projection to the ventrolateral main cuneate nucleus and a complex pattern of projection through the extent of the external cuneate nucleus. In contrast, the cutaneous spinal projection is abundant with extensive filling of axons in the tract of Lissauer and many termination sites in the lateral substantia gelatinosa. Axons enter the lateral gray matter of the cervical spinal cord from the dorsal columns and the dorsolateral funiculus and terminate in the lateral one‐third of the dorsal horn as far rostral as the spinomedullary junction. Axons of the tract of Lissauer form a complex web around the dorsal horn and many penetrate rostrally to the region of the spinomedullary junction, where they terminate among clusters of interstitial cells on and close to the dorsal medullary surface. Cutaneous afferent axons from the dorsal columns turn into the main cuneate nucleus and enter a dense mass of HRP‐reaction product which occupies the most ventrolateral part of the nucleus for its entire length.