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G Teitelman

Publications and source records attributed to G Teitelman.

49 records · Page 3Linked to original sources
PubMed1981

Development of enteric neurons from non-recognizable precursor cells.

Precursors of the neurons that populate enteric ganglia cannot be recognized morphologically when they first enter the gut; therefore embryonic gut in culture, explanted before neurons appear, develops a myenteric plexus that contains cholinergic and serotonergic neurons. The evidence indicates that the developing gut maintains an immature proliferating pool of neuronal precursors that may tentatively and transiently express a given neuronal phenotype. Catecholaminergic expression is an example of such a transient phenotype. It is possible that sequential changes, occurring as a function of gestational age in the enteric neuronal microenvironment and interacting with this persistent pool of neuronal precursors, are responsible for the generation of enteric neuronal diversity. The sequential appearance of the various types of enteric neuron is consistent with this hypothesis. The persistence of a dividing cell population may also be linked to the generation of the large number of enteric neurons.

Animals↗
PubMed1981

Linkage of the brain-skin-gut axis: islet cells originate from dopaminergic precursors.

A population of cells containing the enzymes tyrosine hydroxylase (TH) and dopa-decarboxylase (L-AADC) but not dopamine-B-hydroxylase (DBH) nor phenylethanolamine-N-methyltransferase (PNMT) can be detected with immunocytochemical techniques in the pancreas of mouse embryos at the 11th day of development (E 11). The presence of TH in embryonal pancreas is transient: TH is not observed after E 15. By use of a method for simultaneously detecting two antigens in the same section both TH and glucagon were visualized in the same cell on E 12. Double labelled cells comprised 10% of all stained cells. At E 14.5, some of the cells stained for TH also contained insulin. However, at the time somatostatin appeared no embryonal cells containing TH remained. We conclude that two cell types of the APUD series, i.e., the glucagon and insulin cells of pancreas, arise from transformation, in situ, of cells that transiently express a dopaminergic phenotype. These results suggest that peptide-containing cells in skin, brain and gut are linked by a common embryonic origin. They also raise the prospect that other peptidergic cells of the APUD series may have aminergic precursors.

Animals↗
PubMed1981

Differences in utero in activities of catecholamine biosynthetic enzymes in adrenals of spontaneously hypertensive rats.

1. We sought to determine if catecholamine biosynthetic enzymes of spontaneously hypertensive rats (SHR) differed from those of normotensive Wistar--Kyoto (WKY) and Sprague--Dawley (SD) control rats before birth. 2. By immunocytochemical and biochemical methods we compared strains for the time of appearance and maturation of the enzymes tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH) and phenylethanolamine-N-methyltransferase (PNMT) in sympathetic ganglia and adrenals. 3. The time of appearance of enzymes was identical in all three strains: TH and DBH first appeared in sympathetic ganglia on embryonic day 11 (E11) and in adrenal medulla on E16. PNMT, restricted to adrenal medulla, appeared later on E18. 4. The activity of adrenal TH prenatally on E18 and E21 and at day of birth (P1) in SHR was approximately two fold that in WKY or SD rats. In contrast PNMT was lower in SHR but only on E18. 5. Thus, although the timing of the first expression of adrenergic phenotypes is similar in SHR and normotensive controls, the differences in TH activity in adrenals suggest an enhanced biosynthetic capacity for catecholamines in this strain before birth. 6. We conclude that SHR differ from normotensive rats from the first expression of some of the genes controlling catecholamine biosynthesis.

Adrenal Glands↗
PubMed1981

Transformation of catecholaminergic precursors into glucagon (A) cells in mouse embryonic pancreas.

In embryonic mice, the catecholamine biosynthetic enzyme tyrosine hydroxylase [L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2] can be visualized immunocytochemically in a population of cells in epithelial cords of the developing pancreas. These embryonic catecholamine cells, first seen by day 11, are large and vacuolated and have a folded nuclear membrane. One day later, at day 12, glucagon is first detected immunocytochemically in pancreatic cells similar in location and morphology to the embryonic catecholamine cells. By use of a method for detecting both antigens in the same cell, both the hydroxylase and glucagon can be visualized between day 12 and day 14 in 10-40% of stained cells. From day 14, the number of cells stained for hydroxylase decreases; they cannot be detected after day 18. In contrast, the cells containing glucagon increase during development and persist throughout life. Endocrine cells of the embryonic pancreas also contain dopa decarboxylase but not dopamine-beta-hydroxylase or phenylethanolamine-N-methyl transferase. In adult mice, small cells containing tyrosine hydroxylase but differing in location and morphology from the embryonic catecholaminergic cells are seen in pancreatic islets. The adult catecholaminergic cells never store glucagon. We suggest that adult glucagon (A)-containing cells arise from transformation in situ of cells that transiently express a catecholaminergic (probably dopaminergic) phenotype. These results suggest that one class of peptidergic cells may arise from transformation of an aminergic precursor.

Animals↗
PubMed1980

Catecholamine biosynthetic enzymes are expressed in replicating cells of the peripheral but not the central nervous system.

We sought to determine whether the precursors of catecholamine-containing neurons in the developing peripheral and central nervous systems of chickens and rats express the biosynthetic enzymes tyrosine hydroxylase [THase; tyrosine 3-monooxygenase; L-tyrosine, tetrahydropteridine: oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2] or dopamine beta-hydroxylase [DBHase; 3,4-dihydroxyphenylethylamine, ascorbate:oxygen oxidoreductase (beta-hydroxylating), EC 1.14.17.1], prior to the time they withdraw from the cell cycle. Chicken embryos (stages 26-27) were injected with [3H-thymidine and 4 hr later were prepared for the simultaneous demonstration of radioautographically labeled nuclei in immunoreactive THase cells. The brains and sympathetic chains of rat fetuses (days E12-E14), exposed for 2 hr to [3H]thymidine, were treated similarly except that peripheral tissues were stained with a specific antibody to DBHase as well as anti-THase. In the peripheral nervous system of both chicken and rat, nuclei of THase-containing cells were radioautographically labeled. DBHase-containing cells in the peripheral nervous system of rats were also labeled and thus are noradrenergic. THase was localized in cells of the brain of the same rat fetuses beginning on day E12 (no THase was detected on day E11 or E11.5) in the mantle layer of the ventral mesencephalic and rostrolateral rhombocephalic cellular groups; however. THase-containing cells in the central nervous system did not incorporate [3H]thymidine. We conclude that, during development, the adrenergic neuronal precursors of the peripheral nervous system but not of the central, have the capacity to synthesize catecholamines before they withdraw from the cell cycle. Differences in the maturation of peripheral and central neurons may be related to differences in their embryological origin.

Animals↗
PubMed1979

Appearance of catecholamine-synthesizing enzymes during development of rat sympathetic nervous system: possible role of tissue environment.

We sought to determine, in rat embryo, when and at what site in their migration cells derived from the neural crest differentiate into sympathetic neuroblasts. This has been accomplished by immunocytochemical detection, within the cells, of the enzymes catalyzing catecholamine biosynthesis-tyrosine hydroxylase [TH; tyrosine 3-monooxygenase, L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating), EC 1.14.16.2] dopamine-beta-hydroxylase [DBH; 3,4-dihydroxyphenylethylamine,ascorbate:oxygen oxidoreductase (beta-hydroxylating), EC 1.14.17.1)]-and, as a marker of prospective adrenal medullary cells, the enzyme phenylethanolamine N-methyltransferase (PNMT; S-adenosyl-L-methionine:phenylethanolamine N-methyltransferase, EC 2.1.1.28). TH and DBH, not detected in the neural crest, appear almost simultaneously in cells of the thoracic sympathetic ganglia in 11-day-old embryos, and in abdominal and lumbar ganglia 1-2 days later, thereby exhibiting a characteristic rostral-caudal gradient of differentiation. Cells stained for TH and DBH are seen in the gut wall from day 11 to day 14, but not thereafter. Cells stained for TH and DBH appear in the adrenal anlage at day 15. However, PNMT is not detected in the adrenal until day 17 of development, and is present only in the sympathoblasts in contact with the adrenal cortex. Treatment of pregnant rats with dexamethasone failed to accelerate the appearance of PNMT in the embryo or to initiate its expression in cells of other sympathetic organs. We conclude that neural crest cells express a noradrenergic phenotype only after leaving the neural crest and that these cells are labile with respect to their neurotransmitter and are capable of transformation in response to environmental stimuli.

Adrenal Glands↗
PubMed1976

Regional variations of choline-acetyltransferase in the chick embryo optic lobe.

The specific activity of CAT and AChE was determined in different regions of the chick embryo optic lobe at several stages of development. Regional differences in CAT activity appeared in 9-day-old tectum, being the posterobasal area the one with higher enzymatic activity. On the other hand, at 6th and 13th day of development, the levels of AChE and CAT are similar throughout the optic lobe.

Acetylcholinesterase↗