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Results for “DILS”

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At least 181 records · Page 10Linked to original sources

PubMed1998

Non-adrenergic, non-cholinergic neurons innervating the guinea-pig trachea are located in the oesophagus: evidence from retrograde neuronal tracing.

The possibility that non-adrenergic, non-cholinergic (NANC) neurons innervating the guinea-pig trachea may be located within the oesophagus has been investigated using an in vitro retrograde tracing technique. The cervical trachea and oesophagus were excised from guinea-pigs and Dil was applied to a 5 mm region of the trachealis muscle. These preparations were maintained in organotypic culture for 3 days and processed for immunohistochemistry. A mean of 44 (4 neural cell bodies in the oesophageal myenteric plexus were found to be labelled by Dil. The vast majority of these neurons contained nitric oxide synthase, vasoactive intestinal polypeptide and neuropeptide Y. It is suggested that the population of neurons identified in this study are postganglionic parasympathetic neurons mediating NANC relaxation of the trachealis muscle in this species.

Animals↗

PubMed1999

Rat retinal ganglion cells culture enriched with the magnetic cell sorter.

The magnetic cell sorter (MACS) technique was applied to isolate retinal ganglion cells (RGCs) for culture. RGCs were labeled retrogradely with 1.1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (Dil). Subsequently retinal cell suspensions were incubated with biotinylated anti-rat Thy-1 antibody and MACS Streptavidin MicroBeads, and then applied onto the column in the magnetic fields. Cells attached on the column were flashed out without magnetism and plated on glass cover slips. RGCs were enriched to 31.0% of all cells with MACS from 0.55% before applying onto the magnetic column. Mean diameters of Dil-labeled cells were significantly larger than those of unlabeled cells. All cells with soma diameter over 11 microm were labeled. The number of viable RGCs were counted in the 10 fields of six cultures at a magnification of x200; the mean numbers on the 2nd, 7th and 14th culture-day were 53+/-3, 24+/-2 and 21+/-3, respectively (mean +/- SEM, n = 6). Thus, the MACS technique was confirmed to be useful for enrichment of RGCs and long-term study of cultured RGCs.

Animals↗

PubMed2001

Optic nerve regeneration within artificial Schwann cell graft in the adult rat.

We investigate whether an artificial graft made by cultured Schwann cell, extracellular matrix (ECM) and trophic factors can provide the environment for the regeneration of retinal ganglion cell (RGC) axons in adult rats. Six kinds of artificial grafts were used: ECM (control); ECM and Schwann cells; ECM, Schwann cells and either nerve growth factor, brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT-4); ECM, Schwann cells, BDNF and NT-4, combined with intravitreal injection of BDNF. The grafts were transplanted onto the transected optic nerve. RGC regeneration was evaluated by dil retrograde labeling, immunohistochemistry, and electron microscopy at 3 weeks post-operation. The degree of dil labeled RGC was approximately 2% for ECM alone, and 10% for ECM and Schwann cells (p < 0.01). The labeling increased to approximately 20% by administration of neurotrophins. The addition of intravitreous BDNF injection resulted in highest labeling percentage of 30%. Immunohistochemical study showed that axons were association with GAP-43 and cell adhesion molecules. Neurotrophin receptors (Trk-A and Trk-B) were detected in nerve fibers both in the retina and in the graft. Remyelination was seen by electron microscopic observation. These results demonstrate that the regeneration of RGC axons is induced with the use of cultured Schwann cells and ECM as promoting factors for regrowth. The degree of regeneration was significantly increased by neurotrophins in the grafts and in the vitreous.

Animals↗

PubMed1999

Long-term observation on the changes of somatotopy in the facial nucleus after nerve suture in the cat: morphological studies using retrograde labeling.

To examine the time course of plasticity of the cranial nucleus during axonal regeneration, we followed the topographical reorganization of the cat facial nucleus (FN) up to 24 months after facio-facial nerve suture using retrograde labeling methods. The trunk of the temporal-zygomatico-orbital and both superior and inferior buccolabial branches (defined as main branch) of the facial nerve was cut and sutured again under ketamine hydrochloride anesthesia. At 11-722 days after nerve suture, Fast Blue (FB) and 1,1'-dioctadecyl-3, 3, 3', 3'-tetramethylindocarbocyanine perchlorate (Dil) or horseradish peroxidase (HRP) were injected into the distal part of the sutured main branch and the unoperated posterior auricular branch, respectively. Until about 3 months after suture, the topographical pattern in FN was similar to that observed in normal cats. At about 4 months after suture, FB-labeled motoneurons were distributed not only in the lateral part (including intermediate, dorsal and ventrolateral divisions) but also in the medial subdivision of FN. After a survival period of 18-24 months, FB-labeled neurons were found all over the FN, and their number increased significantly. Interestingly, in the longer survival cases, we noticed that the Dil- or HRP-labeled posterior auricular branch motoneurons also showed a tendency to distribute outside the medial region. The present study showed that somatotopic disorganization starts at around 4 months after suture, which seems to be somewhat slower than that in rats, and continues until a much later postoperative period. Furthermore, we suggested a possibility that the regeneration of one branch may affect the somatotopy of the unoperated nerve branch. These phenomena may contribute to aberrant facial nerve functions such as abnormal associated movement and facial spasm observed after nerve injury.

Amidines↗

PubMed1999

Mesencephalic innervation of the vibrissal follicle-sinus complex in the mouse embryo.

Peripheral projections of neurones whose cell bodies lie in the mesencephalic nucleus of the fifth cranial nerve, situated between the central grey and mesencephalic reticular formation, were studied in mouse embryos aged between day 9 and 15 and in postnatal day 1 mice. Nonspecific neural antibody staining allowed visualisation of the developing cranial nerves, in particular the descending mesencephalic tract. This facilitated successful dissection of the descending mesencephalic tract and trigeminal ganglion in the heads of fresh mouse embryos and postnatal mice. The fluorescent dye, 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (Dil), was injected into the descending mesencephalic tract in mouse embryos aged 12.5, 13.5 and 15 days of gestation and also into postnatal day 1 mice. Following a period of incubation, 100 microm sections were viewed under visible light and episcopic fluorescence. Mesencephalic neurones were observed to pass superiorly over the trigeminal ganglion and enter the maxillary division to innervate vibrissal follicle-sinus complexes, whilst none was observed innervating mandibular and maxillary intraoral structures. There was no fluorescent labelling in non-Dil injected control specimens. Using a highly specific neuronal tracer, this study shows that mesencephalic neurones in the periphery project exclusively to follicle sinus complexes in the developing mouse embryo and remain at least until postnatal day 1. These observations, contrary to those made in other animals, indicate a species specificity of mesencephalic peripheral projections.

Animals↗

PubMed1998

Synthesis and biological activity of chimeric structures derived from the cytotoxic natural compounds dolastatin 10 and dolastatin 15.

The natural cytotoxic compounds dolastatins 10 and 15 exhibit great similarities in structure and in their biological activity profiles. Two compounds (1 and 2) formed by interchanging the dolaisoleuine residue of dolastatin 10 and the MeVal-Pro dipeptide of dolastatin 15 were synthesized in order to evaluate the possible equivalence of these units. These compounds can be considered as chimeras of dolastatins 10 and 15 formed by the N-terminal part of the former and the C-terminal part of the latter and vice versa. Both analogues exhibited a marked decrease in their cytotoxic activity but showed similar differential cytotoxicity with regard to the cell lines assayed compared with the parent compounds. HT-29 cell line was the least sensitive one. However, this activity was in the nanomolar level and close to that of vincristine. The differences in their effect on tubulin polymerization were less pronounced. We confirmed the already known crucial role of the Dil residue in this assay. The nonequivalence of the Dil unit and the MeVal-Pro dipeptide probably reflects modification in the relative positions of the N-dimethylamino and the phenyl moieties.

Animals↗

PubMed1999

Effect of diltiazem on cardiac remodeling in rats assessed by Doppler echocardiography and mRNA expression.

The purpose of this study was to examine the effect of diltiazem on cardiac dysfunction and the change in cardiac gene expression after myocardial infarction in rats. On the first day after myocardial infarction, rats were randomly assigned to a diltiazem treatment (Dil, n = 7) or an untreated group (MI, n = 8). We then performed Doppler echocardiographic examinations on the rats and measured their hemodynamics at 4 weeks after myocardial infarction. Following these measurements, their cardiac mRNA was analyzed. Diltiazem decreased the mean aortic pressure and heart rate. Left ventricular end-diastolic pressure (LVEDP) and central venous pressure (CVP) increased to 18 +/- 2 mmHg and 5 +/- 1 mmHg (P < 0.01). Diltiazem reduced LVEDP to 14 +/- 1 mmHg (P < 0.05), but it did not change CVP. The weight of the right ventricle in MI was significantly larger than in the control rats (control, n = 7, 0.46 +/- 0.02 g/kg vs. MI, 0.81 +/- 0.06 g/kg; P < 0.01). The left ventricular end-diastolic dimension (LVDd) in MI increased to 8.8 +/- 0.3 mm (P < 0.01, control, 6.1 +/- 0.3 mm). Diltiazem prevented an increase in the weight of the right ventricle (0.69 +/- 0.03 g/kg, P < 0.05) and LVDd (7.7 +/- 0.2 mm, P < 0.05 to MI). The rats within MI showed systolic dysfunction, defined by a decreased ejection fraction (control, 67 +/- 2% vs. MI, 36 +/- 3%, P < 0.01), and diastolic dysfunction, defined by the E-wave deceleration rate (control, 13.4 +/- 1.6 m/s2 vs. MI, 30.4 +/- 3.4 m/s2; P < 0.01). Diltiazem significantly prevented systolic and diastolic dysfunction. The increases in beta-MHC, ANP, and collagen type I and III mRNAs in the noninfarcted left ventricle and right ventricle were significantly suppressed by treatment with diltiazem. alpha-Skeletal actin increased in MI, and alpha-skeletal actin was more increased with Dil. In conclusion, diltiazem prevents cardiac dysfunction and morphological change due to left ventricular remodeling after experimental myocardial infarction.

Actins↗

PubMed1992

Lipid utilization by human lymphocytes is correlated with high-density-lipoprotein binding site activity.

The nature and physiological importance of high-density lipoprotein (HDL) binding sites on unstimulated (resting) and mitogen-activated (blast) human peripheral blood lymphocytes were investigated. Specific HDL binding on resting and blast T-lymphocytes was saturable at 50 micrograms of 125I-HDL/ml and of high affinity, with Kd values of 8.1 x 10(-8) M and 6.5 x 10(-8) M, respectively, and Bmax. values of 79 ng and 180 ng/mg of cell protein respectively at 4 degrees C. Binding of HDL double-labelled with fluorescent dioctadecylindocarbocyanine (Dil) and isotope (125I) as well as of single fluorescence- or isotope-labelled HDL was inhibited competitively by HDL apoproteins. Studies of the cholesterol flux between the cells and HDL showed that HDL, low-density lipoprotein (LDL) or BSA at a concentration of 100 micrograms/ml in the tissue culture medium did not result in a significant difference in exogenous [3H]cholesterol efflux from the cell membrane at 37 degrees C. Proliferating T-blasts incorporated more cholesterol from HDL or LDL than did resting lymphocytes. When the cells were pulsed with 125I-HDL and chased in fresh lipid-free medium, up to 80% of the radioactivity released was not precipitable with trichloroacetic acid. This percentage decreased in a competitive manner when unlabelled HDL was present in the chase incubation medium. Finally, cultivation of lymphocytes with conditioned medium from macrophages increased Dil-HDL binding/uptake, while it was decreased by mevinolin-induced inhibition of hydroxymethylglutaryl-coA reductase. In conclusion, human lymphocytes possess a HDL binding site (receptor) responsible for lipid binding/uptake and concomitant internalization and degradation of apoproteins from HDL, but not for reverse cell membrane cholesterol transport. The activity of the binding site is up-regulated during cell proliferation and down-regulated during cell growth suppression.

Adult↗

PubMed1997

Cranial anomaly of homozygous rSey rat is associated with a defect in the migration pathway of midbrain crest cells.

Craniofacial development of vertebrates depends largely on neural crest contribution and each subdomain of the crest-derived ectomesenchyme follows its specific genetic control. The rat small eye (rSey) involves a mutation in the Pax-6 gene and the external feature of rSey homozygous embryos exhibits craniofacial defects in ocular and frontonasal regions. In order to identify the mechanism of craniofacial development, we examined the cranial morphology and migration of cephalic crest cells in rSey embryos. The chondrocranial defects of homozygous rSey embryos primarily consisted of spheno-orbital and ethmoidal anomalies. The former defects appeared to be brought about by the lack of the eye. In the ethmoid region, the nasal septum and the derivative of the medial nasal prominence were present, while the rest of the nasal capsule, as well as the nasal and lachrymal bones, were totally absent except for a pair of cartilaginous rods in place of the nasal capsule. This suggests that the primary cranial defect is restricted to the lateral nasal prominence derivatives. Dil labeling revealed the abnormal migration of crest cells specifically from the anterior midbrain to the lateral nasal prominence in homozygous rSey embryos. Pax-6 was not expressed in the crest cells but was strongly expressed in the frontonasal ectoderm. To determine whether or not this migratory defect actually resides in environmental cues, normal midbrain crest cells from wild-type embryos were labeled with Dil and were orthotopically injected into host rSey embryos. Migration of the donor crest cells into the lateral nasal prominence was abnormal in homozygous host embryos, while they migrated normally in wild-type or heterozygous embryos. Therefore, the cranial defects in rSey homozygous embryos are due to inappropriate substrate for crest cell migration towards the lateral nasal prominence, which consistently explains the cranial morphology of homozygous rSey embryos.

Animals↗

PubMed1996

Characterization of excitatory and inhibitory motor neurons to the guinea pig lower esophageal sphincter.

BACKGROUND & AIMS: The lower esophageal sphincter is innervated primarily by enteric motor neurons. The somata of excitatory and inhibitory motor neurons were identified and mapped. METHODS: Retrograde labeling in organotypic culture and immunohistochemistry were used to identify motor neuron somata. RESULTS: 1,1'-Didodecyl-3,3,3',3'-tetramethyl indocarbocyanine perchlorate (Dil) on the left side of the sphincter labeled descending motor neurons located up to 26 mm along the esophagus and locally (within 2 mm) and gastric motor neurons. Dil applied to the right side of the sphincter labeled descending and local motor neurons but very few gastric motor neurons. Inhibitory motor neuron cell bodies, identified by nitric oxide synthase immunoreactivity, accounted for 86% +/- 4% (n = 6) of descending motor neurons and 53% +/- 4% of local motor neurons labeled from the right side. Excitatory motor neurons, immunoreactive for choline acetyltransferase, accounted for 20% +/- 3% (n = 6) of descending motor neurons and for 47% +/- 4% of local motor neurons. All motor neurons were unipolar, but inhibitory motor neurons were significantly larger than excitatory neurons. CONCLUSIONS: The lower esophageal sphincter is innervated by local excitatory and inhibitory motor neurons and by descending esophageal inhibitory neurons. The oblique muscle, supplied by gastric motor neurons, is closely associated with the gastroesophageal junction.

Animals↗

PubMed1989

The effect of cyclosporin A on rat pancreatic B-cell: interaction with the calcium-antagonist diltiazem.

Cyclosporin A (CyA) was fed to male Wistar rats in a dose of 5, 10 or 50 mg/kg b.wt. for 7 days. In another experimental procedure 10 mg/kg b.wt. CyA was given for 7 days combined with Diltiazem (DIL) 6.25 mg/kg b.wt. once daily ip. Glucose stimulated insulin secretion from the isolated perfused pancreas was investigated in these animals. Total insulin secretion (ng/50 min) was not affected after feeding 5 mg/kg b.wt. CyA, but was significantly decreased with 10 and 50 mg/kg b.wt. CyA. The biphasic insulin secretion was reduced after 5 mg/kg b.wt. CyA during the initial peak (0-10 min) but not during the second peak (10-50 min), whereas after 10 and 50 mg/kg b.wt. CyA both peaks nearly reached base-line levels. DIL markedly increased the initial peak (0-10 min) after feeding CyA 10 mg/kg b.wt., whereas the second peak was not affected. Our results demonstrate a toxic effect of CyA on the pancreatic B-cell, which might be partly abolished by calcium-antagonists.

Animals↗

PubMed1985

Structural organization of interphase 3T3 fibroblasts studied by total internal reflection fluorescence microscopy.

We studied the laminar organization of 3T3 fibroblast cells growing on glass slides by use of total internal reflection illumination to excite fluorescence emission (TIRF) from labeled molecules and stained cellular compartments that are very close to the cell-substrate contact region. Mitochondria, distant from the contact regions and stained with the water-soluble cationic dye, dil-C3-(3), fluoresced only as the glass/cytoplasm critical angle was approached. A similar result was obtained when the nuclei were stained with Hoechst dye 33342. From this measured angle a cytoplasmic refractive index in the range 1.358-1.374 was computed. The plasma membrane of 3T3 cells was stained with dil-C18-(3), and the cytoplasmic compartment was stained with fluoresceinyl-dextran (FTC-dextran) or with carboxyfluorescein. We have demonstrated a high degree of correspondence between the low-reflectance zones in the reflection interference image of a live cell and the TIRF images of both the plasma membrane and cytoplasmic compartment. TIRF photometry of selected contact regions of cells provided data from which the absolute separation of cell and substrate was computed. From a population of 3T3 cells microinjected with fluorescein-labeled actin, motile and adherent interphase cells were selected for study. For adherent cells, which displayed fluorescent stress fibers, the TIRF image was composed of intense patches and less intense regions that corresponded, respectively, to the focal contact and close-contact zones of the reflection-interference image. The intense patches corresponded to the endpoints of the stress fibers. Cells of motile morphology, which formed some focal contacts and extensive close-contact zones, gave AF-actin TIRF images of relatively even intensity. Thin lamellar regions of the cytoplasm were found to contain concentrations of actin not significantly different from other close-contact regions of the cell. The major analytical problem of TIRF microscopy is separation of the effects of proximity to substrate, refractive index, and fluorescent probe concentration on the local brightness of the TIRF image. From our results, it appears possible to use TIRF microscopy to measure the proximity of different components of substrate contact regions of cells.

Actins↗

PubMed1985

Electric field-induced redistribution and postfield relaxation of low density lipoprotein receptors on cultured human fibroblasts.

The lateral mobility of unliganded low density lipoprotein-receptor (LDL-R) on the surface of human fibroblasts has been investigated by studying the generation and relaxation of concentration differences induced by exposure of the cultured cells to steady electric fields. The topographic distribution of receptors was determined by fluorescence microscopy of cells labeled with the intensely fluorescent, biologically active LDL derivative dioctadecylindolcarbocyanine LDL (dil(3)-LDL), or with native LDL and anti-LDL indirect immunofluorescence. Exposure of the LDL-receptor-internalization defective J. D. cells (GM2408A) to an electric field of 10 V/cm for 1 h at 22 degrees C causes greater than 80% of the cells to have an asymmetric distribution of LDL-R; receptors accumulate at the more negative pole of the cell. In contrast, only 20% of LDL-internalization normal GM3348 cells exposed to identical conditions have asymmetrical distributions. Phase micrographs taken during electric-field exposure rule out cell movement as the responsible mechanism for the effect. In both cell types, postfield labeling with the F-actin-specific fluorescent probe nitrobenzoxadiazole-phallacidin shows that no topographic alteration of the actin cytoskeleton accompanies the redistribution of cell surface LDL-Rs, and indirect immunofluorescence labeling of the coat protein clathrin shows that coated pits do not redistribute asymmetrically. Measurements of the postfield relaxation in the percentage of GM2408A cells showing an asymmetric distribution allow an estimate of the effective postfield diffusion coefficient of the unliganded LDL-R. At 37 degrees C, D = 2.0 X 10(-9) cm2/s, decreasing to 1.1 X 10(-9) cm2/s at 22 degrees C, and D = 3.5 X 10(-10) cm2/s at 10 degrees C. These values are substantially larger than those measured by photobleaching methods for the LDL-R complexed with dil(3)-LDL on intact cells, but are comparable to those measured on membrane blebs, and are consistent with diffusion coefficients measured for other unliganded integral membrane receptor proteins by postfield-relaxation methods.

Cell Membrane↗

PubMed1996

Dilation of the influenza hemagglutinin fusion pore revealed by the kinetics of individual cell-cell fusion events.

We have monitored kinetics of fusion between cell pairs consisting of a single influenza hemaglutinin (HA)-expressing cell and a single erythrocyte (RBC) that had been labeled with both a fluorescent lipid (Dil) in the membrane and a fluorescent solute (calcein) in the aqueous space. Initial fusion pore opening between the RBC and HA-expressing cell produced a change in RBC membrane potential (delta psi) that was monitored by a decrease in Dil fluorescence. This event was followed by two distinct stages of fusion pore dilation: the flux of fluorescent lipid (phi L) and the flux of a large aqueous fluorescent dye (phi s). We have analyzed the kinetics of events that occur as a result of transitions between a fusion pore (FP) and a solute permissive fusion pore (FPs). Our data are consistent with a fusion pore comprising six HA trimers.

3T3 Cells↗

PubMed1982

Diffusion of low density lipoprotein-receptor complex on human fibroblasts.

Diffusion of the complex consisting of low density lipoprotein (LDL) bound to its receptor on the surface of human fibroblasts has been measured with the help of an intensely fluorescent, biologically active LDL derivative, dioctadecylindocarbocyanine LDL (dil(3)-LDL). Fluorescence photobleaching recovering and direct video observations of the Brownian motion of individual LDL-receptor complexes yielded diffusion coefficients for the slow diffusion on cell surfaces and fast diffusion on membrane blebs, respectively. At 10 degrees C, less that 20 percent of the LDL-receptor complex was measurably diffusible either on normal human fibroblasts GM-3348 or on LDL-receptor- internalization-defective J.D. cells GM-2408A. At 21 degrees and 28 degrees C, the diffusion fractions of approximately 75 and 60 percent, respectively, on both cell lines. The lipid analog nitrobenzoxadiazolephosphatidylcholine (NBD-PC) diffused in the GM-2408A cell membrane at 1.5x10(-8) cm(2)/sec at 22 degrees C. On blebs induced in GM-2408A cell membranes, the dil(3)-LDL receptor complex diffusion coefficient increased to approximately 10(-9) cm(2)/s, thus approaching the maximum theoretical predictions for a large protein in the viscous lipid bilayer. Cytoskeletal staining of blebs with NBD- phallacidin, a fluorescent probe specific for F-actin, indicated that loss of the bulk of the F-actin cytoskeleton accompanied the release of the natural constraints on later diffusion observed on blebs. This work shows that the internalization defect of J.D. is not due to immobilization of the LDL-receptor complex since its diffusibility is sufficient to sustain even the internalization rates observed in the native fibroblasts. Nevertheless, as with many other cell membrane receptors, the diffusion coefficient of the LDL-receptor complex is at least two orders of magnitude slower on native membrane than the viscous limit approached on cell membrane blebs where it is released from lateral constraints. However, LDL-receptor diffusion may not limit LDL internalization in normal human fibroblasts.

Actins↗

PubMed1984

A time-lapse video image intensification analysis of cytoplasmic organelle movements during endosome translocation.

Vital fluorescence staining has been used in conjunction with time-lapse video image intensification microscopy to analyze the distribution and movement of endosomes, lysosomes, and mitochondria in cultured rat ovarian granulosa cells. Exposure of 5-d granulosa cell cultures to pyrene-concanavalin A (P-Con A) or 3,3'-dioctadecylindocarbocyanine-labeled low-density lipoprotein (dil-LDL) at 4 degrees C results in the formation of randomly distributed endosomes 10 min after warming to 37 degrees C that exhibit saltatory motion for 20 min. If granulosa cells are labeled at 4 degrees C with both P-Con A and dil-LDL and warmed to 37 degrees C, both ligands are found within the same endosomes which migrate centripetally to the cell center where label accumulates within phase-dense structures by 60 min. The initial endosome saltations occur over short distances (mean distance = 4.6 micron) with a mean velocity of 0.03 micron/s. Endosome saltations then cease and are followed by a gradual centriptal migration of endosomes to the cell center where they accumulate and fuse with phase-dense structures. The second phase of movement involves a continuous, unidirectional migration of endosomes over distances ranging from 5 to 40 micron at a mean velocity of 0.05 micron/s. Lysosomes were simultaneously visualized as acridine orange-staining, phase-dense structures in control cells and cells exposed to fluorescent ligands. In untreated cells, lysosomes are dispersed throughout the cytoplasm and undergo bidirectional saltations covering a mean distance of 8.7 micron with a mean velocity of 0.3 micron/s. Lysosomes redistribute centripetally to the perinuclear region of the cell by saltatory movement within 20 min of exposure to ligand. Mitochondria were visualized with the fluorescent dye rhodamine 123 in granulosa cells labeled with P-Con A and were found to redistribute to the cell center coincident with endosomes. The microtubule-disrupting agent nocodazole was found to inhibit lysosome saltations and all phases of endosome movement. Taxol, a microtubule-stabilizing agent, partially impaired lysosome movement and led to a redistribution of lysosomes into linear aggregates surrounding the nucleus. Taxol was also found to inhibit endosome movement. The data indicate that (a) endosome movement proceeds initially by saltation and later by a nonsaltatory centripetal migration in association with mitochondria, that (b) lysosomes and endosomes undergo a temporally distinct but spatially similar change in cytoplasmic distribution, and that (c) microtubules are required for the directed translocation of endosomes and lysosomes towards the cell center.

Animals↗

PubMed2002

Dietary NaCl influences the organization of chorda tympani neurons projecting to the nucleus of the solitary tract in rats.

Prior research has shown that maintained exposure to either a low or high NaCl diet from conception to adulthood is associated with changes in NaCl solution intake and neural responses of the chorda tympani (CT) nerve. The present study examined the influence of maintained exposure to a low or high NaCl diet on the central organization of CT neurons projecting to the nucleus of the solitary tract (NST). Three groups of rats were reared and maintained on regular chow containing either basal 0.1%, intermediate 1.0% or high 6% NaCl from conception to adulthood. The fluorescent marker Dil was applied to the CT for characterization of afferent terminations and efferent cell body labeling in the brainstem. The total NST area occupied by CT afferent fibers was the same for all three dietary groups. However, the pattern of CT innervation differed such that there was an enlarged dorsal terminal field in the high group. There were no group differences in body and brain weight, or in efferent labeled neurons. Thus, Dil has been demonstrated to be an effective transport marker of the gustatory system and the parameters of dietary NaCl exposure that influence the pattern of the CT fibers projecting to the NST have been further clarified.

Animals↗

PubMed1989

Characteristics of specific bindings of nitrendipine and PN200-110 to various crude membranes: induction of irreversible bindings by UV irradiation.

The characteristics of the specific bindings of [3H]nitrendipine (Nit) and [3H](+)PN200-110 (PN) to crude membranes from rat skeletal, cardiac, and uterine muscle and whole brain were investigated, with special interest in the effect of UV irradiation on these bindings. The specific bindings of [3H]Nit and [3H](+)PN to these crude membranes were saturable and reversible. The specific bindings of [3H]Nit to all these membranes except crude skeletal membranes was maximum in the presence of 0.15 M NaCl plus 1 mM CaCl2 and minimal in the absence of these ions, but the specific bindings of [3H](+)PN to these crude membranes was not affected significantly by these ions. A calcium agonist and antagonists inhibited the specific bindings of [3H]Nit and [3H](+)PN to these crude membranes, the order of their inhibitory effects on specific [3H]Nit bindings being roughly Nit greater than or equal to (+)PN greater than or equal to (-)PN much greater than Bay K 8644 (Bay) greater than verapamil (Ver) greater than diltiazem (Dil). In crude skeletal membranes only, PN caused significant stereospecific inhibition. The order of inhibitions of specific [3H](+)PN bindings to these crude membranes was generally (+)PN greater than Nit greater than or equal to (-)PN greater than Bay much greater than Ver greater than or equal to Dil. In all these crude membranes, UV irradiation completely prevented decrease in the amount of specific binding of [3H](+)PN binding on addition of excess unlabeled (+)PN. These findings suggested that [3H]Nit and [3H](+)PN bind to voltage-sensitive calcium channels in crude membranes from rat skeletal, cardiac, and uterine muscle and whole brain, and that UV irradiation changes the specific bindings of [3H]Nit and [3H](+)PN from reversible to irreversible bindings.

Animals↗