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PubMed1985

Morphology and serotonergic innervation of physiologically identified cells of the guinea pig's myenteric plexus.

Ganglion cells of the myenteric plexus of the guinea pig were physiologically classified as to cell type using intracellular microelectrodes containing horseradish peroxidase (HRP). Interganglionic fiber tracts were then stimulated in an attempt to elicit slow excitatory postsynaptic potentials (EPSPs) in the impaled cells. The presence or absence of a slow EPSP was noted, following which the cells were injected with HRP through the recording micropipette and finally were incubated with tritiated 5-hydroxytryptamine ([3H]-5-HT; 0.5 microM) and desmethylimipramine (10 nM). The preparations were examined by light and electron microscopy (EM) for which the physiologically identified, HRP-injected neurons were demonstrated histochemically and serotonergic nerve terminals were simultaneously demonstrated radioautographically. Forty-seven cells were physiologically identified, injected with HRP, and studied by light microscopy. Of these, 22 were also fully analyzed by electron microscopy. The sample included 13 type I/S cells (6 analyzed by electron microscopic radioautography), 16 type II/AH cells (10 analyzed by electron microscopic radioautography), and 18 nonspiking (NS) cells (6 analyzed by electron microscopic radioautography). Slow EPSPs were only observed in type II/AH cells. All five of the fully analyzed subset of type II/AH cells that manifested a slow EPSP were contacted by serotonergic terminals. These terminals were found on 7 of 10 type II/AH cells, 2 of 6 type I/S cells, and 0 of 6 NS cells. Serotonergic terminals, therefore, contacted type II/AH cells (p less than 0.05) and especially those that showed a slow EPSP (p less than 0.005) more frequently than other types of ganglion cells. Morphologically, cells with short, stubby dendrites were reproducibly found to be type I/S cells, and glia could be recognized by their astrocytic appearance; however, cell shape did not otherwise correlate with physiological cell type. These data are compatible with and provide support for the hypothesis that 5-HT is one of the mediators of slow EPSPs in the myenteric plexus.

Animals↗

PubMed1984

Uptake and processing of remnants of chylomicrons and very low density lipoproteins by rat liver.

In the rat, chylomicron remnants and very low density lipoprotein (VLDL) remnants are taken up into the liver by high affinity processes and appear to undergo degradation by lysosomes. The relationship of this catabolic process to the known pathways of uptake and degradation of low density lipoproteins (LDL) and the involvement of nonparenchymal cells are addressed in these studies. We have utilized both light and electron microscopic radioautography to determine whether the pathway of intracellular transport and catabolism resembles that established for LDL in hepatocytes. Radioiodinated plasma VLDL remnants and lymph chylomicron remnants were injected into femoral veins of rats and the livers were fixed by perfusion 3 to 30 minutes later. Quantitative light microscopic radioautography showed little or no accumulation of grains over Kupffer cells. Electromicroscopic radioautography confirmed these observations and, in addition, demonstrated that very few grains were associated with endothelial cells. The processing of the remnant particles closely resembled that of LDL. Following an initial association of grains with the parenchymal cell plasma membrane, frequently in regions in close proximity to clathrin-coated endocytic pits, the grains were found in endocytic vesicles just beneath the plasma membrane. By 15 minutes the grains were found over multivesicular bodies located in the Golgi-lysosome region of the cell. Thirty minutes after injection, radioautographic grains began to be associated with secondary lysosomes. These data indicate no significant role for nonparenchymal cells in the internalization and subsequent degradation of triglyceride-rich lipoproteins, and provide evidence that the processing of remnants as well as LDL follows the classical pathway of receptor-mediated endocytosis.

Animals↗

PubMed1993

Postnatal development and aging of esophageal epithelium in mouse: a light and electron microscopic radioautographic study.

DNA synthesis and fine structure of the esophageal epithelium of ddY mouse in different age groups, from neonatal to senescent, were investigated by light and electron microscopic radioautography after 3H-thymidine labeling in vitro. At 1-3 days after birth, the esophagus was lined with two cell types, ciliated and nonciliated cells. From 1 week on, ciliated cells could not be found. At 2 weeks, the superficial cells still possessed nuclei and short microvilli on the apical plasma membranes. From 1 month, the superficial cells became keratinized and the microvilli on the apical plasma membrane disappeared. With aging of the mice, the epithelia became markedly thick. These results show that disappearance of ciliated cells, keratinization of superficial cells and increase of the thickness are the main changes in structure of mouse esophageal epithelium from neonatal to senescent ages. By light microscopic radioautography, labelled cells were almost confined in the basal layer, regardless of the aging stages. The highest labeling index was recorded at 1 day after birth, then decreased with age. By electron microscopic radioautography, silver grains indicating DNA synthesis were observed in nuclei. As compared with those of unlabelled cells in the basal layer, the nuclei and nucleoli of labelled cells were larger, with fewer cell organelles. The present study provides, for the first time, the basic quantitative data regarding cell proliferation of mouse esophageal epithelium from neonatal to senescent stage.

Aging↗

PubMed1983

Collagen biogenesis and assembly into fibrils as shown by ultrastructural and 3H-proline radioautographic studies on the fibroblasts of the rat food pad.

To examine whether collagen is assembled into fibrils within or outside fibroblasts, the connective tissue of the rat foot pad was investigated by electron microscopy and by radioautography at times varying from 4 min to 3 days after an intravenous injection of 3H-proline. The fibroblasts of the rat food pad are long polarized cells with the nucleus at one end, the Golgi apparatus in the center, and a region with long processes at the other end. This region contains secretory granules and is considered to be the secretory pole of the cell. In the Golgi apparatus the stacks of saccules are separated from rough endoplasmic reticulum (rER) by groups of "intermediate vesicles" including similarly structured tubules which may be over 300 nm long and are referred to as "intermediate tubules." The Golgi saccules exhibit distended portions which differ at the various levels of the stack. On the cis side, the distentions tend to be spherical and contain fine looping threads; in the middle of the stack, they are cylindrical and present distinct straight threads; whereas on the trans side, they are again cylindrical, but the straight threads are grouped in parallel aggregates. Between these cylindrical distentions and the secretory granules, there are transitional forms within which thread aggregates are packaged more and more tightly. Finally, the fibroblasts are associated with two types of collagen fibrils: extracellular ones arranged into large groups between the cells and intracellular ones located within long intracytoplasmic channels. Quantitative radioautography after 3H-proline injection reveals that the number of silver grains per unit area reaches a peak over the rER at 4-10 min, Golgi apparatus at 40 min, secretory granules at 60 min, and extracellular collagen fibrils at 3 h. At no time are intracellular collagen fibrils labeled. Qualitative observations further indicate that spherical Golgi distentions are mainly labeled at 40 min, and cylindrical distentions, at 60 min. In addition, from 20 min to 3 hr, some lysosomal elements are labeled. The biogenetic pathway leading to the formation of collagen fibrils is interpreted as follows.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1987

Dynamic histology of the antral epithelium in the mouse stomach: V. Proliferation gradient from the gland base to the isthmus at various times of day.

The surface epithelium of the mouse pyloric antrum invaginates into blind-ended tubules whose proliferative activity was investigated by using light microscopy and 3H-thymidine radioautography. Adult, male, CD1 mice were habituated to 12 hr of light (0600-1800 hr) alternating with 12 hr of darkness. Groups of four were given an injection of 40 mu Ci of 3H-thymidine per animal and killed 1 hr later at 0600, 1200, 1800, and 2400 hr. The glands at the base of the tubules and the adjacent isthmi were serially cross-sectioned, and 0.5-micron-thick sections were prepared for radioautography. By using morphological criteria, glands were divided into five levels from their base to the isthmus (which was considered as being a sixth level). Proliferative activity was estimated by measuring the proportion of cells incorporating 3H-thymidine (labeling index) and the proportion of cells undergoing mitosis (mitotic index). The labeling index was found to decrease gradually from a high value in the isthmus to a relatively low one in the gland base; and this was observed at four times of the day. Similar gradients were observed in the mitotic index. Moreover, significant circadian variation was disclosed at most levels by comparing either labeling or mitotic index at four different times of the day. The labeling index tended to peak at the transition from dark to light (0600 hr) and drop at the transition from light to dark (1800 hr).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

Radioautographic comparison of RNA synthesis patterns in the epithelial cells of mouse pyloric antrum following 3H-uridine and 3H-orotic acid injections.

RNA synthesis was examined in the epithelial cells of the mouse pyloric antrum using radioautography 20 min after injection of either 3H-uridine or 3H-orotic acid. The epithelium of the mouse antrum was known to invaginate into blind tubular units composed of mucous cells arranged from base to top into a gland, an isthmus, and a pit. These were subdivided into segments and, after radioautography, silver grains were counted over cell nuclei in each segment. Following 3H-uridine injection, silver grains were present over all nuclei but were more abundant over those of the isthmus than of the gland or the pit. When nuclei were examined in the electron microscope, nucleoplasmic as well as nucleolar silver grains were more numerous in the isthmus than in the pit or gland. Following 3H-orotic acid injection, silver grains were again present over all nuclei; but maximal incorporation appeared to be in pit cell nuclei where, by electron microscopy, it was mainly assigned to the nucleoplasm. When the incorporation was calculated per whole nucleus, however, it was less in pit cell than in isthmal cell nuclei. Even so, the proportion of label in pit cell nuclei was much greater than after 3H-uridine injection. The interpretation of these findings is based on the fact that isthmal cells are immature, whereas cells migrating from the isthmus to become gland or pit cells show increasing differentiation. The immature cells of the isthmus incorporate both uridine and orotic acid more effectively than do the differentiated cells of pit and gland. Since silver grain counts over nuclei provide an index of the rate of RNA synthesis, this synthesis proceeds more actively in the isthmus than in the pit or gland. This is true of ribosomal RNA synthesis, as shown by nucleolar grain counts, and of other RNA's synthesis, as shown by nucleoplasmic grain counts. It seems, however, that while uridine is involved in the synthesis of all types of RNA, orotic acid is mainly implicated in the synthesis of the heterogeneous RNA from which the messenger RNA arises.

Animals↗

PubMed1989

An electron microscopic study of mitosis in mouse duodenal crypt cells confirms that the prophasic condensation of chromatin begins during the DNA-synthesizing (S) stage of the cycle.

The phases of mitosis were examined in the columnar cells at the base of duodenal crypts in adult male mice given an intravenous injection of 3H-thymidine and sacrificed 20 min later. The duodenum was fixed by immersion into glutaraldehyde-formaldehyde, and the cells were examined in the electron microscope, with or without processing for radioautography. Interphase nuclei are characterized by the distribution of chromatin; aside from the cortical chromatin spread along nuclear envelope and nucleolus, there are chromatin accumulations that belong mainly in two different classes: 1) numerous chromatin "specks" ranging in size from about 5 to 70 nm and averaging 47 nm; 2) a few roughly circular or elongated chromatin "packets" measuring from 70 to 230 nm. Early prophase nuclei differ mainly by a large increase in the number of chromatin packets to 20-30 or more per nuclear profile; their average diameter is 128 nm. During mid-prophase, the chromatin packets enlarge gradually to an average 221 nm diameter. Between mid- and late prophase, there is a further increase in diameter to 679 nm. At metaphase, the packets take on the appearance of mature chromosomes, and their diameter increases to 767 nm. At anaphase, daughter chromosomes migrate to each pole, where they fuse into a compact chromatin mass. At telophase, nucleoplasmic areas progressively enlarge within the chromatin mass and separate strands of chromatin, which gradually become segmented into chromatin clumps. Counts of mitotic cells show a high proportion of prophase and telophase nuclei. Calculation from the counts yields the duration of the phases, that is, 5.6, 0.2, 0.1, and 1.6 hr, respectively, for pro-, meta-, ana-, and telophase. Finally, radioautography 20 min after 3H-thymidine injection shows labeling in 54% of the interphase nuclei, 85% of early prophase nuclei, and 73% of mid-prophase nuclei, while there is no label in late prophase, metaphase, anaphase and telophase nuclei. In confirmation of previous light microscopic work, the S stage of the cycle begins when a cell is in interphase and continues through the early prophase and part of mid-prophase. Moreover, the main sites of DNA synthesis are the chromatin specks during interphase and the cortical chromatin during early and mid-prophase. The chromosome condensation taking place in the meantime may be separated into two main steps: 1) a slow, moderate condensation of the chromatin packets during early and mid-prophase and 2) a rapid, pronounced one during late prophase and prometaphase when the packets become chromosomes.

Anaphase↗

PubMed1978

Progenitor cells of erythroblasts: an in vitro investigation of erythropoietin-responsive cells of guinea pig bone marrow.

The experiments were designed to test whether or not erythroblast progenitor cell function could be demonstrated in a morphological cell type designated as "transitional cells." Two cell fractions, were obtained from the bone marrow of normal and polycythemic guinea pigs. One fraction (F1) was enriched in transitional cells and contained few, if any, other cell types which could be considered as candidates for erythropoietin responsive cells (ERC). The other fraction (F2) contained undifferentiated blast cells as well as transitional cells. The effect of human urinary erythropoiesis stimulating factors (ESF) on heme synthesis was compared in these two fractions by measuring 59Fe incorporation into heme. ESF was more effective in stimulating heme synthesis in guinea pig bone marrow cells than homologous sera obtained from anemic or hypoxic animals. The majority of ERC sedimented in F2, but the stimulation index was comparable in the two fractions. It was confirmed by radioautography that the ESF response in F1 was due to the generation of proerythroblasts and basophilic erythroblasts that incorporated 55Fe. The generation of these cells in F1 was dependent on the addition of ESF to the cultures, whereas 55Fe-labeled erythroblasts were recovered from cultured of F2 not supplemented with ESF. ESF induced a proportion of transitional cells to incorporate 55Fe in both F1 and F2. Transitional cells were the only cell type in which heme synthesis was dependent on ESF. in other cells of clearly nonerythroid morphology (mononuclear phagocytes and reticular cells), 55Fe incorporation occurred independent of ESF. Although the fractionation procedure employed is unsuitable for the separation of ERC from bone marrow, it permitted the enrichment of transitional cells, a cell type defined by morphology. Radioautography with 55Fe identified a proportion of these cells as ERC in both F1 and F2 fractions of bone marrow obtained from normal and polycythemic guinea pigs. Although there may be other cell types in F2 capable of responding to ESF, the present studies show that some transitional cells function as progenitors of erythroblasts because they respond to ESF by initiation of heme synthesis and by transformation into the earliest recognizable erythroid cells.

Animals↗

PubMed1988

On the presence of intermediate cells in the small intestine.

In the small intestine, the presence of transitional cells or cells intermediate between Paneth cells and goblet cells has been reported frequently for 100 years. Light microscopy and, more recently, fine structural studies have indicated that secretory granules observed in intermediate cells share some morphologic characteristics with those of granular goblet cells and of Paneth cells. In order to verify if intermediate cells in the jejunum and ileum of the adult mouse have functional similarities with either granular goblet or Paneth cells, we have studied the incorporation of sulfur-35 by radioautography and the localization of lysozyme by immunocytochemistry. After radioautography, goblet cells and, to a lesser extent, granular goblet cells had incorporated sulfur-35, whereas Paneth cells and intermediate cells were completely negative. Immunolocalization of lysozyme was done by using rabbit anti-rat lysozyme and protein A-peroxidase. After demonstration of peroxidase activity, only Paneth cells were stained and intermediate cells were negative. Therefore, intermediate cells do not contain sulfomucin or lysozyme, and they are functionally different from goblet and Paneth cells. Their function remains unknown.

Animals↗

PubMed1990

Visualization of sulfur-containing components associated with proliferating chondrocytes from rat epiphyseal growth plate cartilage: possible proteoglycan and collagen co-migration.

Electron microscopy of epiphyseal growth plate cartilage from normal 4-5-week-old rats has revealed extensive fibrillar aggregates and globules in the pericellular spaces of proliferating chondrocytes. These cells contained small globules and diffusely coiled, fine filaments located within large, membrane-invested vacuoles. All such structures were observed after a variety of different tissue fixation regimes, including glutaraldehyde, osmium tetroxide, and potassium pyroantimonate. The fibrillar aggregates and globules were often overlapping and intermeshed and extended to 0.5 micron in length from their point of origin at cell membranes. Vacuoles were usually found at the periphery of cells, and some, by membrane fusion with the cell envelope, appeared contiguous with extracellular spaces wherein their contents could be discharged. Fine filaments and globules were occasionally observed in the Golgi complex and cisternae of endoplasmic reticulum of the chondrocytes. Further characterization of the cellular and pericellular components by electron microscopic radioautography, electron probe microanalysis, and electron spectroscopic imaging indicated the presence of sulfur, a result suggesting these aggregates, filaments, and globules in part represent proteoglycans in various stages of synthesis, secretion, and assembly. Additional radioautography utilizing 3H-proline implied that filament bundles are also composed of collagen, a result posing the possibility that this protein and the putative proteoglycans may co-migrate both intracellularly and within pericellular matrices. In extracellular matrices adjacent to cell lacunae, the fibrillar aggregates appeared in close association with typical collagen type II fibrils, an observation providing evidence for proteoglycan-collagen network formation in this region of the rat epiphysis. These microscopic and analytical data in situ would support certain studies in vitro of proteoglycan-collagen type II and IX association and are important in describing the interaction of such cartilage components ultimately involved in matrix formation.

Animals↗

PubMed1993

Dynamics of epithelial cells in the corpus of the mouse stomach. IV. Bidirectional migration of parietal cells ending in their gradual degeneration and loss.

The life story of parietal cells has been investigated in the corpus of the mouse stomach using electron microscopy and 3H-thymidine radioautography. Parietal cells are scattered in the four regions of the unit. On the average 3.6 cells are in the pit, 6.2 in the isthmus, 5.6 in the neck, and 10.6 in the base. Parietal cells do not divide. They arise from partially differentiated pre-parietal cells, which are believed to be derived in the isthmus from the three subtypes of granule-free cells: undifferentiated cells, pre-pit cell precursors, and pre-neck cell precursors. Radioautography indicates that the transformation of granule-free cells into pre-parietal cells takes at least one day. The pre-parietal cells, of which there are 0.6 per unit on the average, develop into parietal cells through three successive stages. Stage 1 is characterized by small immature cells that are identified by long apical microvilli. Stage 2 is characterized by larger cells, about one-third the size of parietal cells, and by an incipient canaliculus and a few apical tubulovesicles. Stage 3 is characterized by the expansion of the canalicular and tubulovesicular systems as well as mitochondrial enlargement, which cause the pre-parietal cell to gradually approach the size of, and eventually become, a parietal cell. This cell sequence mainly takes place in the isthmus, but may extend to the neck region. Continuous infusion of 3H-thymidine confirms that parietal cells originate in the isthmus and that they migrate in two directions: some go outward to the pit and the others migrate inward to the neck and eventually to the base. It has been estimated that for every six parietal cells produced per month in the isthmus, three migrate to the pit and three migrate to the neck to eventually reach the base. While almost all parietal cells in the isthmus and neck appear normal, a large proportion of those reaching the pit (21%) and base (23%) undergo gradual alteration and degeneration. After the ensuing death, parietal cells are eliminated in one of two major ways: 1) extrusion into the gastric lumen, if they appear necrotic, or 2) phagocytosis by a neighboring cell or even by an invading connective tissue macrophage, if they are apoptotic. The overall turnover time of parietal cells averages 54 days.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1994

Morphological changes and cellular proliferation in mouse colon during fetal and postnatal development.

To document regional structural and cellular proliferation changes in the developing mouse colon, tissues from fetal, suckling, and weanling mice were analyzed by light microscopy (LM), transmission electron microscopy (TEM), scanning electron microscopy (SEM), [3H]-thymidine incorporation studies, and radioautography. The proximal and distal colon were studied independently at all ages. At 17-18 days of gestation, the mouse proximal colonic mucosa was projected into high and low longitudinal folds disposed in a V-shaped pattern. From birth up to 9 days, the mucosal folds observed by SEM can easily be misinterpreted as being a succession of high and low villus-like structures at LM level. TEM study confirmed the presence of highly specialized absorptive cells in the upper halves of the mucosal folds during this period. No recognizable crypts were noted at birth. Instead, LM and radioautography showed the presence of cell aggregates developing at the base of the epithelium at all levels of the mucosal folds. These cell aggregates evolved into rudimentary crypts giving fully differentiated crypts by day 16 with radiolabeled cells located in the midcrypt portion. As opposed to the proximal segment, a flat mucosa interspersed with well defined short crypts at birth was observed in the distal colon. During the following days, crypts further developed and by 16 days, the radiolabeled epithelial cells were still exclusively located at the base of the crypt. TEM observations illustrated that specialized cells as those found in the proximal segment did not differentiate in this segment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1981

Normal and abnormal retinal projections following the crush of one optic nerve in goldfish (Carassius auratus).

Optic nerve regeneration was examined with [3H]proline radioautography in fish that had one nerve crushed. Fibers had not yet grown beyond the crush site at 2 days post-crush (PC) and were at the optic chiasm by 4-5 days PC. By 6 days PC the fibers had reinnervated the rostral pole of the contralateral tectum, the lateral geniculate nucleus and area pretectalis dorsalis and ventralis. Area preopticus, nucleus opticus dorsolateralis and nucleus opticus commissurae posterior were partially reinnervated by 8 days PC. At this time numerous abnormal targets were labeled, including nucleus rotundus, nucleus isthmi, cerebellum, pituitary gland and ipsilateral optic tectum. Optic fibers also entered the posterior, intertectal and horizontal commissures, as well as tractus rotundus, the tectocerebellar, tectobulbar and mesencephalocerebellar tracts. In addition, fibers with the contralateral optic tectum were not restricted to their usual laminae. They were distributed from the superficial edge of the tectum to the ventricle. At 32 days PC only the normal retinal projections were evident, and all of the anomalous projections had disappeared. The anomalous projections may have either retracted or degenerated or become undetectable with radioautography.

Animals↗

PubMed1992

Development and birthdates of vasoactive intestinal peptide immunoreactive neurons in the chick proventriculus.

To gain insight into the mechanisms regulating expression of transmitter phenotypes in the enteric nervous system, we have studied the development and birthdate of vasoactive intestinal peptide immunoreactive (VIP-IR) myenteric neurons in the chicken proventriculus (secretory portion of the avian stomach) by a combination of immunocytochemistry and radioautography. The appearance and numbers of VIP-IR neurons in whole mounts of the myenteric plexus from chick embryos and chickens were examined. We found that VIP-IR neurons first appeared at embryonic day (E) 5.5-6.5 in the distal part of the proventriculus. At E7.5, VIP-IR neurons were found singly, in pairs, or in small groups, which together with unlabeled cells formed primitive myenteric ganglia. VIP-IR fibers were found within the developing fiber tracts which connected the ganglia. The number of VIP-IR neurons was found to be maximum in the E15.5 embryo and to decline to 68% of maximum in the 4 week old chicken. Birthdate studies were performed by application of either single pulses or cumulative doses of [3H]-thymidine to embryos between E3 and E14. Whole mounts of the myenteric plexus from the proventriculus of these embryos were immunostained for VIP at E10 or E17. The whole mounts were subsequently sectioned and processed for radioautography. We found that VIP-IR myenteric neurons were born between E3 and E10 with a peak at E7. Most cells underwent terminal division between E5 and E9. These data will be useful in determining the time and conditions when cells make decisions about transmitter phenotypes.

Aging↗

PubMed1993

Detection of the 5-HT1A receptor and 5-HT1A receptor mRNA in the rat bowel and pancreas: comparison with 5-HT1P receptors.

We tested the hypothesis that the rat bowel and pancreas contain 5-HT1A receptors. 3H-8-hydroxy-2-(di-n-propylamino)tetralin (3H-8-OH-DPAT) was used as a radioligand. Binding of 3H-8-OH-DPAT to membranes derived from the myenteric plexus and the pancreas was investigated by rapid filtration. Alternatively, radioautography was employed to locate 3H-8-OH-DPAT binding sites in frozen sections of unfixed bowel or pancreas. An excess of 5-HT (10 microM) was used to define nonspecific binding. Saturable, high affinity binding of 3H-8-OH-DPAT to enteric (Kd = 2.8 +/- 1.1 nM; Bmax = 83.8 +/- 4.3 fmol/mg protein) and pancreatic (Kd = 6.6 +/- 1.3 nM; Bmax = 44 +/- 2.2 fmol/mg protein) membranes was found. The binding of 3H-8-OH-DPAT to enteric and pancreatic membranes was inhibited by 8-OH-DPAT, NAN-190, and spiperone. In contrast, the binding of 3H-8-OH-DPAT to enteric and pancreatic membranes was not inhibited by 5-carboxyamidotryptamine, or by a variety of compounds known to bind to other subtypes of 5-HT receptor. Digoxigenin-labeled oligonucleotides were found to detect mRNA encoding the 5-HT1A receptor in a subset of neurons in myenteric and submucosal ganglia. In contrast, 5-HT1A mRNA was not found in the pancreas. Radioautography revealed that the highest density of 3H-8-OH-DPAT binding sites was found in the stomach. These sites were especially numerous in the lamina propria adjacent to gastric glands, and in myenteric ganglia. Pancreatic 5-HT1A receptors were located on nerves, lymphoid tissue (especially the capsule of nodes), and on cells scattered in the pancreatic parenchyma. The concentration of 3H-8-OH-DPAT binding sites in the rat bowel and pancreas was less than that of 3H-5-HT binding sites; however, the distribution of 3H-8-OH-DPAT binding sites was similar to that of sites that bind 3H-5-HT. It is concluded that the rat gut and its extension in the pancreas contains 5-HT1A receptors. Many, if not all, of the nerve cells and processes that express 5-HT1A receptors express 5-HT1P receptors as well. The function of these receptors in the physiology of the entero-pancreatic innervation remains to be determined.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

PubMed1990

Cell proliferation in developing human stomach.

Cell proliferation during morphogenesis of human stomach was investigated using radioautography and biochemical determinations of [3H]-thymidine incorporation into DNA. Labeling indices in the epithelium, mesenchyme and muscle layer were established on radioautographs and the heights (mm) of the gastric glands were measured between 10 and 17 weeks of gestation. At 11-12 weeks, the appearance of the first pit/gland was noted, and the labeling index ranged from 9.2 to 10.2%. Labeled cells were present at all levels of the stratified epithelium. Between 14 and 16 weeks, the total epithelial labeling index declined sharply (8.1 to 5.4%) with a concomitant increase of the height of the pit/gland structures (0.055 to 0.080 mm). High proliferative activity was also recorded in the mesenchyme and the muscle layer, the labeling indices decreasing between 10 and 17 weeks. The biochemical quantitation of the [3H]-thymidine uptake into the total gastric DNA clearly supported the continuous decrease of the cell proliferation determined by radioautography. Detailed analysis of the epithelium showed that proliferative cells were more numerous at the base of the gland at the earliest stage (11 weeks) but concentrated in the pit/neck regions by 13-14 weeks. As the pit/gland development proceeded (14 to 17 weeks) labeled cells remained more abundant in the pit/neck regions of the gland (10.9%) and were rarely seen on the surface epithelium (2%). The present investigation provides basic quantitative data regarding cell proliferation in developing human stomach, and indicates that the morphogenesis of the gastric glands is correlated with the high proliferative capacity of the pit/neck cells.

Cell Division↗

PubMed1976

[Fc receptors and surface immunoglobulins in cells of hairy cell leukemia].

Using 125I-labelled aggregated IgG in a quantitative assay a strong expression of Fc-receptors was found on the leukemic cells of a patient with hairy cell leukemia. The Fc-receptor activity on these cells was much higher than that on monocytes and B-lymphocytes from normal blood. Surface immunoglobulins were detected by radioautography using radioactively labelled (Fab')2-fragments of monospecific antibodies directed against immunoglobulin heavy chains. Prior to radioautography the cells were stained for the tartrate resistant acid phosphatase. It was found that all cells containing this enzyme bore sigma-chains on their surface. On more than 90% of these cells a simultaneous expression of mu-chains was detected. gamma-Chains could only be demonstrated on cells which were negative for the tartrate resistant acid phosphatase; part of these cells, however, were hairy cells by morphological criteria.

Acid Phosphatase↗

PubMed1989

Histochemical characterization of sensory neurons with high-affinity receptors for nerve growth factor.

Approximately one half of the neurons in the lumbar dorsal root ganglion of adult rats display high-affinity receptors for nerve growth factor (NGF). To ascertain which types of sensory neurons are potentially responsive to NGF, adjacent cryostat sections of rat dorsal root ganglia were processed either for NGF-receptor using radioautography or by one of four histochemical procedures. Histograms of the densities of neuronal labelling by radioiodinated NGF were examined for subpopulations of lumbar sensory neurons with thiamine monophosphatase enzyme activity or with immunoreactivity for calcitonin gene-related peptide (CGRP), substance P, or somatostatin. Virtually all neurons with strong CGRP immunoreactivity had high-affinity NGF binding sites, although some neurons with faintly positive CGRP immunoreactivity lacked such NGF binding. A subpopulation of large neurons, approximately 5% of the total, had dense labelling by 125I-NGF but were not stained by this immunohistochemical technique for CGRP. Of the three major populations of small neurons those with substance P immunoreactivity were consistently and heavily labelled by radioiodinated NGF whereas those with somatostatin immunoreactivity or thiamine monophosphatase activity were not specifically labelled by radioautography. For these primary sensory neurons in mature rats the genes for substance P and CGRP seem to be strongly expressed only in neurons capable of responding to NGF. On the other hand, neurons containing somatostatin and thiamine monophosphatase invariably lack high-affinity NGF receptors.

Animals↗