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J Carlsen

Publications and source records attributed to J Carlsen.

At least 55 records · Page 3Linked to original sources
PubMed1986

The projection from the parataenial thalamic nucleus, as demonstrated by the Phaseolus vulgaris-leucoagglutinin (PHA-L) method, identifies a subterritorial organization of the ventral striatum.

The thalamic projection to the ventral striatum was examined in the rat by immunohistochemistry after iontophoretic injections of Phaseolus vulgaris-leucoagglutinin (PHA-L) into the parataenial thalamic nucleus. A continuous dense terminal field was observed in the nucleus accumbens and the striatal cell bridges, as well as in the adjoining striatal parts of the olfactory tubercle. These observations provide further evidence of the relevance of the ventral striatal concept.

Animals↗
PubMed1986

A correlated light and electron microscopic immunocytochemical study of cholinergic terminals and neurons in the rat amygdaloid body with special emphasis on the basolateral amygdaloid nucleus.

The cholinergic innervation of the rat basolateral amygdaloid nucleus (BL) was determined by the immunocytochemical localization of the acetylcholine biosynthetic enzyme, choline acetyltransferase (ChAT). ChAT-immunoreactive (ChAT-IR) elements were observed throughout the BL in the form of fine puncta and varicose fibers. Electron microscopy revealed that the immunoreactive puncta represented small terminals (0.3-1.2 micron), most of which formed synaptic contacts with unlabeled dendritic shafts or spines. Less frequently, ChAT-IR terminals established synaptic contacts with large neuronal cell bodies, which had all the characteristics of projection neurons as defined on the basis of axonal projections to the ventral striatum. ChAT-IR terminals were sometimes seen to form synaptic contacts with small neuronal cell bodies, including those of ChAT-IR neurons. The ChAT-IR boutons contained pleomorphic clear vesicles of varying size, and the large majority of the synapses were of the symmetric type. Small ChAT-IR neurons were observed in all parts of the BL. Although the ChAT-IR cell bodies varied widely in shape from typical fusiform to round, most had a more or less oval shape with a major diameter of 10-14 micron. Most of the ChAT-IR neurons seemed to display a radial bipolar dendritic pattern, but multipolar cells were also observed. The ChAT-IR neurons contained an indented nucleus, which was often eccentrically located and surrounded by a thin or moderately thin rim of cytoplasm. The results obtained are discussed in relation to a quasi-cortical organization of the BL.

Amygdala↗
PubMed1986

Cholinergic and GABAergic afferents to the olfactory bulb in the rat with special emphasis on the projection neurons in the nucleus of the horizontal limb of the diagonal band.

We have examined the location of cholinergic and GABAergic neurons that project to the rat main olfactory bulb by combining choline acetyltransferase (ChAT) and glutamic acid decarboxylase (GAD) immunohistochemistry with retrograde fluorescent tracing. Since many of the projection neurons are located in subcortical basal forebrain structures, where the delineation of individual regions is difficult, particular care was taken to localize projection neurons with respect to such landmarks as the ventral pallidum (identified on the basis of GAD immunoreactivity), the diagonal band, and medial forebrain bundle. In addition, sections with fluorescent tracers or immunofluorescence were counterstained for Nissl substance in order to correlate tracer or immunopositive neurons with the cytoarchitecture of the basal forebrain. The majority of the cholinergic bulbopetal neurons are located in the medial half of the nucleus of the horizontal limb of the diagonal band (HDB), whereas only a few are located in its lateral half. A substantial number of cholinergic bulbopetal cells are also found in the sublenticular substantia innominata. A small number of cholinergic bulbopetal neurons, finally, are located in the ventrolateral portion of the nucleus of the vertical limb of the diagonal band. At the level of the crossing of the anterior commissure, approximately 17% of the bulbopetal neurons in the HDB are ChAT-positive. The noncholinergic bulbopetal cells are located mainly in the lateral half of the HDB. GAD-containing bulbopetal neurons are primarily located in the caudal part of the HDB, especially in its lateral part. About 30% of the bulbopetal projection neurons in the HDB are GAD-positive. A few GAD-positive bulbopetal cells, furthermore, are located in the ventral pallidum, anterior amygdaloid area, deep olfactory cortex, nucleus of the lateral olfactory tract, lateral hypothalamic area, and tuberomamillary nucleus. The topography of bulbopetal neurons was compared to other projection neurons in the HDB. After multiple injections of fluorescent tracer in the neocortex, retrogradely labeled neurons were concentrated in the most medial part of the HDB, while neurons projecting to the olfactory and entorhinal cortices were located in the ventral part of the HDB. These results show that the cells of the HDB can be divided into subpopulations based upon projection target as well as transmitter content. Furthermore, these subpopulations correspond, at least to a considerable extent, to areas that can be defined on cyto- and fibroarchitectural grounds.

Animals↗
PubMed1985

Use of carboxypeptidase Y in studies of the mode of insertion of cytochrome b5 into lipid vesicles.

Carboxypeptidase Y preparations from baker's yeast have been found to exhibit endopeptidase activity when cytochrome b5 was used as substrate. As the susceptibility of cytochrome b5 to attack by carboxypeptidase Y has been used to distinguish between two modes of insertion of cytochrome b5 into lipid bilayer, one which has the C terminal buried in the lipid bilayer and one which has a free C terminal, caution should be taken when employing carboxypeptidase Y preparations for this type of studies.

Animals↗
PubMed1985

Reconstitution of cytochrome b5 into lipid vesicles in a form which is nonsusceptible to attack by carboxypeptidase Y.

Pig liver cytochrome b5 is reconstituted into lipid vesicles by a method whereby cytochrome b5-lysophospholipid micelles are fused with liposomes. The reconstitution method inserts cytochrome b5 into the lipid bilayer in a mode which renders the C-terminal part of cytochrome b5 nonsusceptible to attack by carboxypeptidase Y. The effect of the lipid composition of the vesicles on the mode of insertion has been examined, when cytochrome b5 is reconstituted using the presently described method and methods previously used to reconstitute this protein, namely the direct incorporation method and the cholate dialysis method.

Animals↗
PubMed1985

Cholinergic projections from the basal forebrain to the basolateral amygdaloid complex: a combined retrograde fluorescent and immunohistochemical study.

We have examined the location of cholinergic and non-cholinergic neurons that project to the rat basolateral amygdaloid nucleus by using choline acetyltransferase (ChAT) immunohistochemistry in combination with retrograde fluorescent tracing on the same tissue section. Since many tracer-and ChAT-positive neurons were identified in basal forebrain areas, including the ventral pallidum, we also stained many of the sections for glutamate decarboxylase, a suitable marker for the delineation of pallidal areas. Cholinergic neurons projecting to the basolateral amygdaloid nucleus were observed in a continuous territory stretching from the dorsal part of ventral pallidum, through sublenticular substantia innominata to ventral parts of globus pallidus and peripallidal areas. Non-cholinergic neurons projecting to the basolateral amygdaloid nucleus were found intermixed within the same structures and constitute approximately 25% of the amygdalopetal projection neurons in these ventral forebrain structures. Since amygdalopetal cholinergic neurons were demonstrated in areas generally recognized as giving rise to cholinergic projections to cerebral cortex, several retrograde double-labeling experiments with two different fluorescent tracers were performed for the purpose of detecting the possible existence of collateral projections. The results obtained showed that the cholinergic basal forebrain neurons in general project to only one forebrain region, and, furthermore, that the cholinergic system consists of partially overlapping subsets of neurons that project to various neocortical and allocortical areas and to the amygdaloid body.

Amygdala↗
PubMed1985

A procedure for removal of interfering phospholipids in the separation and analysis of proteins.

A procedure for removal of phospholipids from aqueous samples is described. It is simple and rapid and can be used generally in cases where phospholipids interfere with spectrophotometric, chromatographic, electrophoretic, or other methods. The procedure is based on the hydrolysis of phospholipids by phospholipase C and removal of the formed diacylglycerol by centrifugation or extraction into an inert, apolar solvent, like petroleum ether, which does not solve or have a denaturating effect on most proteins.

Animals↗
PubMed1984

Quantitative determination of collateral anterior olfactory nucleus projections using a fluorescent tracer with an algebraic solution to the problem of double retrograde labeling.

The bilateral projections of the rat anterior olfactory nucleus (AON) were evaluated using retrograde fluorescent tracers. Competitive effects of these tracers led to severe underestimation of bilaterally projecting neurons, when double-labeled cells were counted. The underestimate was corrected using a numerical approach, which is of general utility for problems in double labeling and requires only a single tracer. With this method we estimated that approximately 63% of AON neurons project bilaterally to the olfactory bulbs, except for the external part which projects exclusively to the contralateral olfactory bulb. No other AON neurons project only to the contralateral bulb.

Animals↗
PubMed1984

An algebraic approach to the detection of multiple markers in complex neuronal systems.

An important class of neuroanatomical problems requires identification of neurons that contain two or more substances. Based on the additivity of neuronal elements that are independently labeled, a simple numerical approach may be applied to these problems. This approach provides a sensitive and viable alternative to direct multiple labeling of endogenous or transported neuronal markers.

Animals↗
PubMed1983

Reconstitution of a protein into lipid vesicles using natural detergents.

A method is described for reconstitution of a protein into lipid vesicles using one of the natural detergents lysophosphatidylcholine or lysophosphatidic acid. The intestinal microvillus enzyme, aminopeptidase N (EC 3.4.11.2) is incorporated into lipid vesicles prepared from a total lipid extract of the microvillus membrane. The method is based on fusion of aminopeptidase-lysophospholipid micelles with liposomes prepared by sonication. The incorporation of the protein into the lipid bilayer is analyzed by gel permeation chromatography and sucrose density gradient centrifugation. The coincidence of the protein and lipid profiles is used to evaluate protein incorporation. The incorporation is visualized by electron microscopy with negative staining. The method has the advantage of using natural detergents, lysophospholipids, which are minor but natural constituents of biological membranes. The method could be of value as a tool in studies of mechanisms of insertion of newly synthesized proteins into biological membranes.

Aminopeptidases↗
PubMed1982

Purification of microvillus membrane vesicles from pig small intestine by immunoadsorbent chromatography.

Microvillus membrane vesicles from pig small intestine, isolated by hypotonic lysis, Mg2+ aggregation of contaminants and differential centrifugation, have been further purified by immunoadsorbent chromatography. The vesicles adhere to an immunoadsorbent prepared by coupling antibodies raised against three of the principal proteins of the brush border membrane (aminopeptidase, sucrase-isomaltase and lactase) to Sepharose 4B. After the contaminants are removed by washing, the adherent vesicles are released from the immunoabsorbent by applying shear forces. The purity of the immunoadsorbed vesicles has been established by electron microscopy and by measuring the activity of marker enzymes. The enrichment factor is 1.17 +/- 0.02 for aminopeptidase and 0.70 +/- 0.05 for 5'-nucleotidase. The contamination of the preparation before immunoadsorption constitutes 10% of the membrane protein and consists mainly of basolateral membrane fragments as judged from marker enzyme determinations and the lipid composition.

Animals↗
PubMed1982

Tracing of two-neuron pathways in the olfactory system by the aid of transneuronal degeneration: projections to the amygdaloid body and hippocampal formation.

Following an olfactory bulb lesion in guinea pig (2 to 3 days), neuronal degeneration occurs in several olfactory-bulb-related areas, primarily in the piriform cortex. The degenerating neurons, which are argyrophilic, are also found in the posterolateral cortical amygdaloid nucleus and the ventrolateral entorhinal cortex. It is suggested that the neurons degenerate because of a transneuronal effect due to a sudden loss of afferent input from the olfactory bulb, although a retrograde effect acting in concert with transneuronal factors cannot be excluded. Terminal degeneration can be identified in several areas outside the olfactory bulb projection area, and is interpreted as degeneration in the axons of the degenerating cortical neurons. Such terminal degeneration, which is best seen 3 to 4 days postoperatively, has been identified in part of the basolateral amygdaloid complex, in the basomedial amygdaloid nucleus, and in the temporal parts of the fascia dentata of the hippocampal formation. Terminal degeneration has also been observed in the deep layers of the anterior olfactory nucleus, the olfactory tubercle, the nucleus of the lateral olfactory tract, and the anterior amygdaloid area. All these projections, apparently, represent the second link in two-neuron pathways, where mitral or tufted cells in the olfactory bulb make up the first neuron. This interpretation was confirmed in control experiments in which areas of argyrophilic neurons coincided with the location of retrogradely labeled neurons following injection of fluorescent substances into several of the above-mentioned areas of terminal degeneration.

Afferent Pathways↗
PubMed1981

Microvillus membrane vesicles from pig small intestine. Purity and lipid composition.

Microvillus membrane vesicles from pig small intestine were isolated by a method based on hypotonic lysis, Mg2+-aggregation of contaminants and differential centrifugation. The purity of the membrane vesicles were established by measuring the activity of marker enzymes and the RNA and DNA content. The membranes were found free of contamination by other subcellular membrane fragments, except for a minor contamination with basolateral plasma membranes. The lipid composition was established and, based on weight percentage, the membrane contained neutral lipids, phospholipids, neutral glycolipids and gangliosides in the weight ratio of 18 : 50 : 29 : 2%. The amount of individual phospholipids and glycolipids were quantitated. Phosphatidylethanolamine, -choline, -serine, -inositol and sphingomyelin made up 17, 17, 6, 5 and 5%, respectively of the total lipid. The major glycolipids were two monohexosylceramides containing glucose and galactose as the carbohydrate component, a dihexosylceramide containing galactose as the only carbohydrate component and two pentahexosylceramides containing fucose, galactose, glucose and hexosamine (either N-acetylglucosamine or N-acetylgalactosamine) in the molar ratio of 1 : 2 : 1 : 1.

Alkaline Phosphatase↗