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At least 19 recordsLinked to original sources
PubMed1979

Cholinergic stimulants and excess potassium ion increase the fluidity of plasma membranes isolated from adrenal chromaffin cells.

Chromaffin cell membranes from the bovine adrenal medulla were labelled with the hydrophobic fluorescent probe 1,6-diphenyl-1,3,5-hexatriene, and the fluorescence polarization (P) of the membrane suspensions was measured as a function of temperature. The P versus t profiles, between 20 and 37 degrees C, showed two linear regions separated by a break in the vicinity of 30 degrees C, reflecting a change in the phase behaviour of the constitutent lipids. Decreases in P values at higher temperature indicated progressive fluidization of the lipid bilayer. Previous incubation with either acetylcholine (0.5 mM) or nicotine (50 microM) produced further fluidization, the extent of which depended on the presence of added Ca2+ (2.2 mM). Thus, the flow activation energy, delta E, between approx. 30 and 37 degrees C was 9.1 kcal/mol for acetylcholine and 8.8 kcal/mol for acetylcholine plus Ca2+, as compared to 7.9 kcal/mol in the absence of acetylcholine and Ca2+. In the presence of nicotine, delta E was 11.4 kcal/mol when Ca2+ was absent and 9.5 kcal/mol when it was present. The cholinergic blocker, hexamethonium (0.5 mM), abolished the acetylcholine- or nicotine-induced changes. 65 mM K+ produced a similar fluidization, which was reversed by addition of Ca2+. An additive effect was observed when the membranes were incubated with both nicotine and K+, with delta E = 16.6 kcal/mol in the presence of Cas2+. These results indicate a receptor-mediated modulation of the lipid distribution between rigid and fluid regions in the membrane, which could be of importance for stimulated catecholamine secretion in the intact cell.

Acetylcholine↗
PubMed1977

Identification of small intensely fluorescent (SIF) cells as chromaffin cells in bullfrog sympathetic ganglia.

Small intensely fluoresent (SIF) cells were investigated in the ninth and tenth paravertebral sympathetic ganglia of the bullfrog using histochemical and electron microscopic techniques. Fluorescence histochemistry revealed that clusters of SIF cells are sparsely distributed in the ninth and tenth ganglia; the clusters were usually located in the vicinity of blood vessels. Fluorescent processes were not observed emanating from SIF cells. The clusters stained positively for the chromaffin reaction indicating that SIF cells are chromaffin cells. Ultrastructurally, the SIF-chromaffin cells in the sympathetic ganglia appeared virtually identical to the chromaffin cells in the adrenal gland; this includes two cell types that appear morphologically the same as the epinephrine and norepinephrine containing chromaffin cells in the adrenal gland. Efferent synapses from the SIF-chromaffin cells in sympathetic ganglia to sympathetic ganglia to sympathetic neurons were not observed. The SIF-chromaffin cells in bullfrog sympathetic ganglia did not have the morphological characteristics of interneurons; it is suggested that they may function as extra-adrenal chromaffin tissue.

Adrenal Glands↗
PubMed1978

On the chromaffin cells in dog adrenal medulla; with special reference to the small granule chromaffin cells (SGC cells).

Small granule chromaffin cells (SGC cells) were identified in the adrenal medulla of adult dogs. They were small in size and usually showed a high nucleo-cytoplasmic ratio. Cytoplasmic projections were occasionally observed in some of these cells. They contained a variable number of small secretory granules with diameters ranging from 70 to 300 nm, but mostly from 100 to 200 nm. The densities of the secretory granules were variable, ranging from highly dense to less dense. These adrenal SGC cells were rich in free ribosomes and polysomes, but were relatively poor in other cell organelles. Chromaffin cells which were intermediate in their characteristics (IM cells) between the SGC cells and the typical A and N cells were also identified. These IM cells contained both highly electron dense and less dense granules in various proportions. The IM cells were classified into two subgroups, according to the proportions of adrenaline type granules and noradrenaline type granules. One group resembled A cells (IM-A cells) and the other resembled N cells (IM-N cells). Light microscopic histochemical studies of A cells stained with the ammoniacal silver solution demonstrated that they contained a small number of darkly stained granules. Electron microscopic cytochemistry revealed that the electron dense granuls in the SGC cells, IM cells and A cells reacted positively with both the potassium dichromate solution at pH 4.1 and the ammoniacal silver solution.

Adrenal Medulla↗
PubMed1977

Adrenal medulla: chromaffin cells as paraneurons.

Adrenal chromaffin cells are typical paraneurons. They are of neural crest origin, secrete catecholamines and produce action potentials. In addition to adrenaline-storing (A) cells and noradrenaline-storing (NA) cells, a third calss of chromaffin cells is distinguishable. They are characterized by the smallness of the secretory granules, and hence are called small-granule chromaffin (SGC) cells. The SGC cells have two or more, long, axon-like processes, receive a heavy innervation, and contain small synaptic-like vesicles in addition to the dense-cored secretory granules of neurosecretory type. Hence, they are regarded as an intermediate form between both A and NA cells of endocrine function and sympathetic nerve cells. Adrenal chromaffin cells share the basic process of the formation, intracellular transport, and storage of the secretory granules with all the paraneurons. Thus, the secretory granules are formed in the Golgi area and contain mainly peptides. They then incorporate adenine nucleotides and catecholamines and when mature are released by exocytosis. By means of autoradiography, quantitative variations were demonstrated with regard to dopa-, dopamine- and noradrenaline-handling capacities within chromaffin cells of a single class. A similar functional differentiation may possibly be found in paraneurons other than the adrenal chromaffin cells. Hypophysectomy in the mouse suppessed the uptake of 3H-dopamine-derived radio-activity in the chromaffin cells. The SGC cells seemed to increase their number in the hypophysectomized mouse.

Adrenal Medulla↗
PubMed1976

The effects of dbcAMP on adreanl chromaffin cells in organotypic culture.

Chromaffin cells in organotypic cultures of adrenal glands from 19 day rat embryos developed a marked increase in the volume of their rough endoplasmic reticulum (RER) and enlargement of nucleoli in response to 1 mM dibutyryl cyclic AMP (dbcAMP) treatment for 17 days in vitro. 0.1 mM dbcAMP had a similar but less dramatic effect. When dbcAMP was removed from the medium after 11 days in vitro, cells became more like control explants treated with no additives, suggesting the effects of dbcAMP were reversible. ACTH which selectively stimulates adrenal cortical cells had no effect on RER morphology of chromaffin cells. The 'neuronal-like' configuration of dbcAMP treated chromaffin cells is discussed.

Adrenal Medulla↗
PubMed1978

Anti-myosin stains chromaffin cells.

The presence in fixed chromaffin cells of antigenic sites for a myosin antibody was demonstrated using immunofluorescence techniques. Tests on viable cells showed that at least some of the antigenic sites seem to be localized on or close to the cell surface and explained the cell agglutination that occurred with the addition of the myosin antibody to cells isolated by a method described in this paper.

Agglutination Tests↗
PubMed1978

Nerve growth factor-induced fiber outgrowth from isolated rat adrenal chromaffin cells: impairment by glucocorticoids.

Addition of nerve growth factor to cultures of dissociated rat adrenal medullary cells caused fiber outgrowth from chromaffin cells. These fibers exhibited all the characteristics of neurites, particularly the formation of typical growth cones exhibiting intense catecholamine-specific fluorescence. Because this nerve growth factor-mediated neurite outgrowth could be abolished by physiological concentrations of glucocorticoids, it is concluded that the high glucocorticoid concentrations normally present in the adrenal medulla prevent the fiber outgrowth from medullary chromaffin cells in vivo. In dissociated sympathetic neurons the same concentrations of glucocorticoids markedly reduce but do not completely abolish neuronal fiber outgrowth.

Adrenal Medulla↗
PubMed1977

Stimulus-secretion coupling in chromaffin cells isolated from bovine adrenal medulla.

Bovine adrenal chromaffin cells were isolated by removal of the cortex and sequential collagenase digestion of the medulla. The catecholamine secretory function of these cells was characterized with respect to acetylcholine stimulation, cation requirements, and cytoskeletal elements. The dose-response curve for stimulated release had its half-maximum value at 10(-5) M acetylcholine, and maximum secretion was on the average 7 times that of control basal secretion. The differential release of epinephrine versus norepinephrine after stimulation with 0.1 mM acetylcholine occurred in proportion to their distribution in the cell suspension. The cholinergic receptors were found to be predominantly nicotinic. The kinetics of catecholamine release were rapid, with significant secretion occurring in less than 60 sec and 85% of maximum secretion within 5 min. A critical requirement for calcium in the extracellular medium was demonstrated, and 80% of maximum secretion was achieved at physiologic calcium concentrations. Stimulation by excess potassium (65 mM KCl) also induced catecholamine secretion which differed from acetylcholine stimulation in being less potent, in having a different dependence on calcium concentration, and in its response to the local anesthetic tetracaine. Tetracaine, which is thought to inhibit membrane cation permeability, was able to block acetylcholine-stimulated but not KCl-stimulated secretion. The microtubule disrupting agent vinblastine was able to block catecholamine release whereas the microfilament disrupter cytochalasin B had little effect. The results show the isolated bovine chromaffin cells to be viable, functioning, and available in large quantity. These cells now provide an excellent system for studying cell surface regulation of hormone and neurotransmitter release.

Adrenal Medulla↗
PubMed1979

Stress-induced degranulation accompanied by vesicle formation in the adrenal chromaffin cells of the mouse.

Stress was induced in mice by restraining on a board by pinning their limbs followed by immersion of the hind feet in a water bath of 20 degrees C. Fine structure of adrenal chromaffin cells was studied by light and electron microscopy. After 8 to 22 hrs' stress, remarkable decrease in the number of argentaffin granules of the NA cells was demonstrated by light microscopy. By electron microscopy, the decline in the granule number was marked in A, NA and SGC cells. This degranulation was accompanied by theoccurrence of numerous smally cytoplasmic vesicles which often appeared empty but sometimes contained an electron-dense material. Granule-containing invaginations of plasma membrane were frequently seen and were interpreted to represent the exocytotis profiles. The idea that the secretory granule membrane and associated substances might be recovered in the form of cytoplasmic vesicles was thus supported. Exposure of the mouse to restraint plus water immersion stress proved to be a simple method for production of acute and drastic degranulation of the adrenal chromaffin cells.

Adrenal Glands↗
PubMed2010

Human dopamine β-hydroxylase promoter variant alters transcription in chromaffin cells, enzyme secretion, and blood pressure.

BACKGROUND: Dopamine β-hydroxylase (DBH) plays an indispensable role in catecholamine synthesis by converting dopamine into norepinephrine. Here, we characterized a DBH promoter polymorphism (C-2073T; rs1989787; minor allele frequency ~16%) that influences not only gene transcription but also enzyme secretion and blood pressure (BP) in vivo. METHODS: Plasma DBH activity was measured spectrophotometrically. DBH genetic effects on BP were tested in subjects with the most extreme BP values in a large primary care population. Functional effects of promoter variants were studied by site-directed mutagenesis in DBH promoter haplotype/luciferase reporter plasmids transfected into chromaffin cells. Sequence motifs were predicted from position weight matrices, and endogenous transcription factor binding was probed by Chromatin ImmunoPrecipitation (ChIP). RESULTS: The T-allele of common promoter variant C-2073T was contained in a promoter haplotype that associated with plasma DBH activity, a trait also predicted by that variant itself. Promoter haplotypes including C-2073T predicted BP in the population, and the effect was also referable to C-2073T itself. Computationally, C-2073 disrupted a predicted match for transcription factor c-FOS. Site-directed mutagenesis at C-2073T altered not only basal promoter activity, but also transactivation by c-FOS, as well as the chromaffin cell secretory stimuli nicotine or pituitary adenylate cyclase-activating polypeptide (PACAP). Endogenous c-FOS bound to the motif in chromatin. CONCLUSIONS: These results suggest that DBH promoter variant C-2073T is functional in vivo: this promoter variant seems to initiate a cascade of transcriptional and biochemical changes including augmented DBH secretion, eventuating in elevation of basal BP, and hence cardiovascular risk. The observations suggest new strategies for probing the pathophysiology, risk, and treatment of hypertension.

Animals↗
PubMed1977

Two populations of microvesicles in the SGC (small granule chromaffin) cells of the mouse adrenal medulla.

A second population of cytoplasmic microvesicles was constantly recognized in the SGC (small granule chromaffin) cells of the mouse adrenyl medulla by means of transmission electron microscopy in glutaldehyde/osmium tetroxide-fixed material. The microvesicles were rendered in shape and of mean profile diameter of between 30, 40 nm: some contained several dense precipitates. The vesicles were usually dispersed throughout the cytoplasm among the typical secretory granules of 100-230 nm in profile diameter, though they occasionally formed aggregations. The SGC cells were also characterized by a high nucleus to cytoplasm ratio, rich innervation, and long cytoplasmic processes which were traced up to 30 micrometer. Co-existence of the synaptic-like vesicles and secretory granules in the SGC cells suggests that they may represent an intermediate position between the chromaffin and sympathetic nerve cells.

Adrenal Medulla↗
PubMed1976

Intracellular localization of calcium in the chromaffin cells of the rat adrenal medulla.

The ulstrastructural localization of calcium in the chromaffin cells of the adrenal medulla was carried out by using potassium pyroantimonate during fixation. Calcium-containing deposits were either diffuse within the cytoplasm or associated with membrane-bounded organelles. Variable amounts of precipitates were found within the nucleus and in the Golgi complex. However, the major sites of calcium antimonate deposits were the secretory granules and the mitochondria. The morphological identification of calcium-storing organelles in the adreno-medullary cells may be useful in evaluating the involvement of such intracellular compartments during the secretory process.

Adrenal Medulla↗
PubMed1978

Observations on the localization of labelled amino acid in mouse adrenal chromaffin cells after the injection of L-[4,5-3H] leucine.

The intracellular localization of L-[4,5-3H] leucine in chromaffin cells has been observed using light and electron microscopic autoradiography and the association of the labelled amino acid with particular cell components confirmed by statistical analysis. By making observations at short intervals after a single intravenous pulse of [3H]leucine it has been possible to follow the movement of the isotope from the endoplasmic reticulum through the Golgi complex to the chromaffin granules. No evidence for movement of the label through the Golgi complex was observed in adjacent cortical cells. The time sequence of transport of the amino acid through the various cell organelles was very similar to that observed by previous workers in protein-secreting exocrine cells.

Adrenal Glands↗
PubMed1979

Nerve growth factor-induced transformation of immature chromaffin cells in vivo into sympathetic neurons: effect of antiserum to nerve growth factor.

Pre- and postnatal injections of nerve growth factor, initiated with one dose on day 17 of gestation and continued after birth with daily subcutaneous administration until day 10 of life, produce massive transformation of chromaffin in sympathetic nerve cells in the rat adrenal medulla. Large sympathetic ganglia, absent in controls, adhere to the medial external surface of the gland. Nerve fibers produced by the transformed chromaffin cells invade the inner and outer cortical zones of the organ, producing cell depletion and substantial alteration of the structure of the cortical layers. When the growth factor treatment is initiated after birth, only a partial replacement of chromaffin with nerve cells takes place. The treatment is ineffective after the second postnatal week. Injections of a specific antiserum to nerve growth factor in 17-day-old rat fetuses, which were continued after birth, produce progressive and massive destruction of chromaffin cell precursors and of immature chromaffin cells in the adrenal medullary gland.

Animals↗
PubMed1975

Inhibition of the adrenal chromaffin cell membrane calcium pump by caffeine and various divalent cations.

Caffeine, 50 mM, inhibited ATP-mediated 45Ca uptake by plasma membrane vesicles from bovine adrenal medullary microsomes by 40 percent. Hg++ (0.09 mM) completely inhibited 45Ca uptake, while Cd++ (0.3 mM) and Ba++ (0.3 mM) produced mean depressions of 80 and 41 percent, respectively. 45Ca uptake in the presence of Zn++ (0.3mM) was not significantly different from controls. Inhibition of calcium accumulation in plasma membrane vesicles by these agents was not correlated with their ability to inhibit the enzyme Ca++-ATPase. Caffeine and certain divalent cations may modify secretory responses by inhibiting the active extrusion of calcium through the adrenal medullary plasma membrane.

Adenosine Triphosphatases↗