Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Thalamo-parietal fibers originating from the ventroanterior-ventrolateral (VA-VL) complex in the cat were labeled with Phaseolus vulgaris leucoagglutinin (PHA-L) and examined by light and electron microscopy. PHA-L (2.5% aqueous solution) was injected iontophoretically through micropipets with anodal current pulses into the VA-VL complex. PHA-L-labeled terminals were distributed in the lateral and the suprasylvian gyri in the superficial and deep cortical layers. In layer I, horizontal varicose fibers and terminals were conspicuous in the upper one-third and were widely distributed. In the deeper cortical layers (layers III-V), varicose fibers and terminals were detected in moderate numbers. Electron microscopic examination revealed that the labeled terminals formed asymmetrical synapses on the dendritic spines of spiny neurons. These morphological findings appeared to be consistent with our previous intracellular recordings in this cortex.
 ...
PMID:Morphological features of cat thalamo-parietal projection fibers investigated by PHA-L immunohistochemistry and electron microscopy. 132 31

The entopeduncular nucleus is one of the major output stations of the basal ganglia. In order to better understand the role of this structure in information flow through the basal ganglia, experiments have been performed in the rat to examine the chemical nature, morphology, and synaptology of the projections from the globus pallidus and striatum to the entopeduncular nucleus. In order to examine the morphology and synaptology of pallidoentopeduncular terminals and striatoentopeduncular terminals, rats were subjected to a double anterograde labelling study. The globus pallidus was injected with Phaseolus vulgaris-leucoagglutinin (PHA-L), and on the same side of the brain, the striatum was injected with biocytin. The entopeduncular nuclei of these animals were then examined for anterogradely labelled pallidal and striatal terminals. Rich plexuses of PHA-L-labelled pallidal terminals and biocytin-labelled striatal terminals were identified throughout the entopeduncular nucleus. At the electron microscopic level, the pallidal boutons were classified as two types. The majority (Type 1), were large boutons that formed symmetrical synapses with the dendrites and perikarya of neurones in the entopeduncular nucleus. Type 2 PHA-L-labelled terminals were much rarer, slightly smaller, and formed asymmetrical synapses. It is suggested that the Type 2 boutons are not derived from the globus pallidus but from the subthalamic nucleus. The biocytin-labelled terminals from the striatum had the typical morphological features of striatal terminals and formed symmetrical synapses. The distribution of the postsynaptic targets of the pallidal terminals and the striatal terminals differed in that the pallidal terminals preferentially made synaptic contact with the more proximal regions of the neurones in the entopeduncular nucleus, whereas the striatal terminals were located more distally on the dendritic trees. Examination in the electron microscope of areas where there was an overlap of the two sets of anterogradely labelled boutons revealed that terminals from the globus pallidus and the striatum made convergent synaptic contact with the perikarya and dendrites of individual neurones in the entopeduncular nucleus. In order to examine the chemical nature of the input to the entopeduncular nucleus from the globus pallidus and the striatum, ultrathin sections were immunostained by the postembedding method to reveal endogenous GABA. Three classes of GABA-containing terminals were identified; two of them formed symmetrical synapses and one rare type formed asymmetrical synapses. The combination of the GABA immunocytochemistry and anterograde labelling revealed that both the striatal and pallidal afferents that make symmetrical synapses with neurones in the entopeduncular nucleus, including those involved in convergent inputs, are GABAergic.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:The striatum and the globus pallidus send convergent synaptic inputs onto single cells in the entopeduncular nucleus of the rat: a double anterograde labelling study combined with postembedding immunocytochemistry for GABA. 138 May 17

Projections from the basolateral nucleus of the amygdala (BLA) to the frontal cortex and the striatum were studied by using Phaseolus vulgaris-leucoagglutinin (PHA-L) anterograde tracing technique in the rat. PHA-L injections into the rostral part of the BLA resulted in a dense labeling of fibers with boutons in the dorsal bank of the rhinal fissure and in the lateral and the medial agranular cortex. PHA-L injections into the caudal part of the BLA produced a dense labeling of fibers in the medial surface of the frontal cortex. In most of the cortical regions, labeled fibers were predominantly distributed in two bands: one in the deep part of layers I and II and the other, heavier band, in layers V and VI. PHA-L injections into the rostral BLA resulted in a dense labeling of fibers with boutons in the olfactory tubercle, the rostral and caudolateral portion of the nucleus accumbens, and a large region of the caudate-putamen. The labeled area of the caudate-putamen included the rostroventral area, the central area, and the area caudal to the anterior commissure and dorsal and lateral to the globus pallidus. PHA-L injections into the caudal BLA produced fiber labeling in the most rostromedial area of the caudate-putamen facing the lateral ventricle, the medial portion of the nucleus accumbens, and the lateral septum. In the rostroventral striatum, PHA-L-labeled fibers selectively innervated the matrix compartment that contains abundant somatostatin-immunoreactive fibers. Compartmental segregation was less clear in the caudodorsolateral caudate-putamen and in the nucleus accumbens. Electron microscopy revealed that PHA-L-labeled boutons in the striatum contained abundant, small, round vesicles. These boutons formed asymmetrical synapses with dendritic spines of striatal neurons.
 ...
PMID:Amygdaloid projections to the frontal cortex and the striatum in the rat. 169 28

Phaseolus vulgaris leucoagglutinin (PHA-L) is a plant lectin that is anterogradely transported by neurons in the central nervous system. PHA-L is selectively taken up by cells at iontophoretic injection sites and, when immunohistochemically demonstrated, labels individual neurons completely, including their dendrites, axons, and terminal boutons. PHA-L is generally not taken up by fibers passing through the injection site and, because it produces a Golgi-like staining of even very fine axons over long distances, it is sometimes possible to light microscopically reconstruct individual neurons and their entire axon terminal arbors. When prepared for electron microscopy, the PHA-L-labeled terminals are densely and completely stained, allowing their synaptic relationships to be defined. These properties make PHA-L advantageous for studying the patterns of projection and the modes of termination of select groups of neurons in their target nuclei. We used PHA-L to study the extraretinal innervation of the cat's dorsal lateral geniculate nucleus, a thalamic visual center. Although much is known about the retinal contribution to geniculate synaptic circuitry, relatively little is known about other sources of innervation, even though these provide the majority of synaptic terminals in the nucleus (Guillery: Z. Zellforsch., 96:1-38, 39-48, 1969; Wilson et al.: Proc. R. Soc. Lond. [Biol.], 221:441-436, 1984). We used both light and electron microscopy to describe synaptic circuitry from three extraretinal sources of projections to the lateral geniculate nucleus: the visual cortex, the perigeniculate nucleus, and the parabrachial region of the brainstem. Cortical terminals labeled with PHA-L were small and formed asymmetrical synaptic contacts onto small-caliber dendrites of geniculate neurons. Perigeniculate terminals formed symmetrical synaptic contacts primarily onto small-caliber dendrites, but some synapses were also formed onto the proximal, retinorecipient portions of geniculate dendrites. Parabrachial terminals synaptically contacted the retinorecipient portions of dendritic appendages and shafts, small-caliber dendrites, and the specialized dendritic (F2) terminals of geniculate interneurons. The symmetry of the parabrachial synaptic contacts was variable and was related to the postsynaptic target. Contacts onto dendritic appendages were asymmetrical while those onto dendritic shafts and F2 terminals were symmetrical. Our data suggest that in unlabeled material these brainstem terminals would be difficult to distinguish from cortical or perigeniculate profiles. The positioning of the parabrachial input onto the retinorecipient portions of geniculate dendrites indicates that this projection is well situated to control primary retinal transmission through the nucleus, while the location of most cortical and perigeniculate innervations implicates them in secondary feedback interactions or other aspects of geniculate function.
 ...
PMID:Phaseolus vulgaris leucoagglutinin (PHA-L): a neuroanatomical tracer for electron microscopic analysis of synaptic circuitry in the cat's dorsal lateral geniculate nucleus. 239 62

Efferent projections of rat subthalamic nucleus were studied by use of the axonal transport of phaseolus vulgaris-leucoagglutinin (PHA-L), and the results were analyzed with light and electron microscopes. PHA-L injections in the subthalamic nucleus (STH) resulted in heavy labeling of fiber plexus with en passant boutons and terminals in the pallidal complex, i.e., the entopeduncular nucleus (EP), the globus pallidus (GP) and the ventral pallidum (VP), and the substantia nigra pars reticulata (SNR). Labeling in GP was characterized by two distinct bands of labeled terminals oriented dorsoventrally, whereas labeling in SNR was patchy. STH efferents to the pallidum and SNR displayed a mediolateral topographic organization. With regard to dorsoventral organization, projections to GP were inverted, but those to SNR were not. There were moderate projections to the neostriatum and sparse projections to the frontal cortex, substantia innominata, substantia nigra pars compacta (SNC), pedunculopontine tegmental nucleus, ventral part of the central gray matter including the dorsal raphe nucleus, and the mesencephalic and pontine reticular formation. PHA-L injections in the zona incerta and the lateral hypothalamic area resulted in fiber and terminal labelings in many structures, including the basal forebrain, EP, SNC, and other brainstem areas that overlap with some of the terminal sites of STH projections. Ultrastructural observations of PHA-L labeled processes in GP and SNR revealed that STH terminals in both structures contained small pleomorphic vesicles and formed asymmetrical contacts. These contacts were mainly on dendritic shafts, but some were on somata. It also was observed that the myelinated axons of STH neurons lost their myelin after reaching their target areas and the synaptic boutons arose from relatively thin unmyelinated axons.
 ...
PMID:Efferent projections of the subthalamic nucleus in the rat: light and electron microscopic analysis with the PHA-L method. 243 52

Anterograde tracers, Phaseolus vulgaris leucoagglutinin (PHA-L) and horseradish peroxidase (HRP), were used to study the thalamocortical afferents of the posteromedial barrel subfield (PMBSF) in rat primary somatosensory cortex (SI) at both light- and electron-microscopic levels. The PMBSF, also known as the barrel cortex, can be subdivided into barrel and interbarrel areas on the basis of cytoarchitectonic characteristics. Restricted injections confined to either the ventroposterior medial (VPM) or the rostral part of the posterior (Pom) nucleus allowed us to study and compare their projection patterns to the barrel cortex. We found that the interbarrel area receives inputs exclusively from the Pom, whereas the barrel area receives inputs from both the Pom and VPM. The laminar distributions of these two projections are largely segregated. After an injection of PHA-L or HRP into the VPM, labeled bouton-like swellings are found in layer VI and in layers IV through I of the barrel area, with the highest concentration in layer IV. On the other hand, after an injection of PHA-L or HRP into the Pom, labeled bouton-like swellings are distributed from upper layer V to layer I of the interbarrel area, as well as in layers V and I of the barrel area. Ultrastructural analysis showed that labeled bouton-like swellings of the VPM and the Pom pathways make synaptic contacts onto cortical neurons, and that these contacts are asymmetrical. Therefore, the VPM and the Pom projections are complementary to each other in the barrel cortex, and together they provide thalamic inputs to most layers of both the barrel and interbarrel areas. The differential patterns of terminations of the VPM and the Pom projections in the barrel cortex suggest that they may be involved in different types of cortical processing. Furthermore, our present findings may provide the anatomical basis for two parallel thalamocortical pathways, which previous physiological studies have indicated are each concerned with particular submodalities of somatic information.
 ...
PMID:Thalamic afferents of the rat barrel cortex: a light- and electron-microscopic study using Phaseolus vulgaris leucoagglutinin as an anterograde tracer. 848 92

This paper describes the termination pattern and synaptic connectivity of the pathway from the basolateral nucleus of the amygdala (BLA) to the medial prefrontal cortex (mPFC; areas 25, 32, and 24b) of the rat. Discrete injections of the anterograde tracer Phaseolus vulgaris-leucoagglutinin (PHA-L) were made in the BLA and detailed light microscopical observations made of the distribution of PHA-L labelled fibres and boutons in the mPFC. Labelled fibres were distributed in two tiers: predominantly within deep layer 1/layer 2 and also in layers 5/6. Fibre plexi in layers 2 and 5 were highly varicose. Electron microscopical examination of 120 labelled boutons in area 32 (60 in layer 2 and 60 in layer 5) indicated that 116 (97%) established asymmetrical synaptic contacts with dendritic spines and 4 (3%) were in synaptic contact with small dendritic shafts. No significant differences in target structures were found between layers 2 and 5. The results indicate that BLA input to mPFC in the rat predominantly innervates spine bearing dendrites in layers 2 and 5. This suggests that the neuronal operations of these processes are influenced by direct feedforward excitation from the BLA.
 ...
PMID:Amygdala input to medial prefrontal cortex (mPFC) in the rat: a light and electron microscope study. 878 14

The lateral geniculate nucleus of the rat was injected with the anterograde tracer Phaseolus vulgaris leucoagglutinin (PHA-L) to see if geniculo-cortical axons terminate on vasoactive intestinal polypeptide immunoreactive (VIP-IR) neurons of the primary visual cortex. PHA-L-labelled boutons attached to VIP-IR perikarya and dendrites were identified as presynaptic parts of asymmetrical synapses. This geniculo-cortical projection to VIP-IR cells in the visual cortex and comparable findings in the somatosensory cortex suggest that sensory input from specific thalamic nuclei may influence local circuit inhibition and the metabolic state within the cortical domain via VIP-IR neurons.
 ...
PMID:Geniculo-cortical afferents form synaptic contacts with vasoactive intestinal polypeptide (VIP) immunoreactive neurons of the rat visual cortex. 921 37

Quantitative electron microscopy was used to examine the relative contributions of different types of synapses to the circuitry of the thalamic reticular nucleus (RTN) in the rat. Single RTN cells were injected with Lucifer Yellow (LY) in fixed brain slices and examined after photoconversion; corticothalamic axons and terminals were labeled by anterograde transport of Phaseolus vulgaris-leucoagglutinin (PHA-L); and gamma-aminobutyric acid (GABA)ergic terminals were labeled by postembedding immunocytochemistry. Three types of synapses, made by morphologically distinguishable small terminals (ST), large terminals (LT), and GABAergic terminals, were distributed on all portions of the dendritic trees of injected RTN cells. ST and LT terminals formed asymmetrical, presumed excitatory, synaptic contacts. On proximal dendrites, approximately 50% of the synapses were ST, 30-40% were LT, and 10-25% were GABAergic. On distal dendrites, 60-65% were ST, 20% were LT, and 15% were GABAergic. PHA-L labeling showed that labeled corticothalamic terminals and ST terminals have identical morphological features and the same distribution patterns on RTN dendrites, indicating that the majority of excitatory afferents to RTN neurons are derived from the cerebral cortex. The LT terminals found in smaller numbers are probably derived from collateral axons of thalamocortical relay cells. GABAergic terminals formed by LY-labeled, intra-RTN axon collaterals were relatively few in number, and no dendrodendritic synapses were observed.
 ...
PMID:Predominance of corticothalamic synaptic inputs to thalamic reticular nucleus neurons in the rat. 1049 79

Laminar distribution and synaptic organization of non-cholinergic projections to the medial limbic cortex from the basal forebrain (BF) were studied in rats. To eliminate BF cholinergic neurons selectively, a immunotoxin, 192IgG-saporin, was injected into lateral ventricle, and 7 days later, to label the remaining non-cholinergic elements, Phaseolus vulgaris-leucoagglutinin (PHA-L) was injected into BF. In rats injected with the toxin, PHA-L labeled fibers, presumably originating from the remaining non-cholinergic neurons, were distributed in layers V-VI of the medial limbic cortex. Ultrastructural observation showed that the PHA-L labeled fibers were classified into two categories. One class of the axons provided with numerous passant boutons, whereas the other carried fewer passant varicosities. Both classes of terminals were found to make symmetrical synaptic contacts predominantly with dendritic shafts, together with a large number of degenerating terminals making asymmetrical synapses with dendritic spines, presumably cholinergic in nature. These results suggest that non-cholinergic projections from the BF exert a modulatory effect directly on cortical neurons in the medial limbic cortex.
 ...
PMID:[Non-cholinergic projections from basal forebrain to medial limbic cortex of rat]. 1092 Jun 6


1 2 Next >>