Membranes of chromaffin granules were isolated from the adrenal glands of four different species. The solubilized membrane proteins could be resolved into several bands by polyacrylamide-gel electrophoresis (alkaline and acid gel systems). Two major protein components appeared to be common to the chromaffin granule membranes of ox, horse, pig and man. The various membrane proteins of bovine chromaffin granules were separated by filtration on Sephadex G-200 in the presence of sodium dodecyl sulphate. Two major membrane proteins (A and B) were obtained in purified form. Treatment of protein A with 2-mercaptoethanol before electrophoresis resulted in two more rapidly migrating subunits, whereas protein B was unaffected by mercaptoethanol treatment. The amino acid compositions of the two purified proteins were determined. They are very similar to that of the total membrane proteins but significantly different from that of the chromogranins, the soluble proteins of chromaffin granules.. ...
Dopamine-ß-hydroxylase (DßH), an enzyme which catalyzes the conversion of dopamine to norepinephrine, is the only enzyme of the catecholamine biosynthetic pathway located in the chromaffin granules of adrenal medulla. Within the granules, two populations of DßH exist: a water-soluble fraction found within the granule matrix and a membrane-bound, amphiphilic fraction embedded in the surrounding bilayer. The amphiphilic form was purified to homogeneity following its extraction from the membrane with the non-ionic detergent BRIJ 58. Three steps were required to achieve complete purification: adsorption to ConA-Sepharose, adsorption to DEAE Sephadex A-25, and chromatography on Sephacryl S-200, Sepharose 6B, or Sepharose CL-4B. The presence of 0.1-0.2 mg/ml BRIJ 58 was essential for protein recovery. The enzymatic and structural characteristics of membrane-bound DßH were found to be similar to those of soluble DßH. Initial velocity data indicated a Ping-pong or double-displacement reaction with ...
The bovine homologue of p65, a calmodulin-binding protein located in the membranes of synaptic vesicles and endocrine secretory granules, has been studied by the use of monoclonal antibodies directed against this antigen and against dopamine beta-mono-oxygenase. The protein (apparent molecular mass 67 kDa; pI = 5.5-6.2) is partially degraded by treatment with neuraminidase or endoglycosidase F. Trypsin treatment of intact adrenal chromaffin granules or of granule membranes releases a soluble 39 kDa fragment of p65 which corresponds to the whole of its cytoplasmic domain. This domain contains both the epitope for the monoclonal antibody cgm67 and the calmodulin-binding site. The 20 amino acids at the N-terminus of this fragment are identical to part of the rat p65 sequence.. ...
TY - JOUR. T1 - Molecular cloning of cDNA encoding the C subunit of H+-ATPase from bovine chromaffin granules. AU - Nelson, H.. AU - Mandiyan, S.. AU - Noumi, T.. AU - Morihama, Y.. AU - Miedel, M. C.. AU - Nelson, N.. PY - 1990/12/18. Y1 - 1990/12/18. N2 - A cDNA encoding subunit C of the V-ATPase from bovine chromaffin granules was cloned and sequenced. The gene encodes a hydrophilic protein of 382 amino acids with a calculated molecular weight of 43,989. Hydropathy plots revealed no apparent transmembrane segments and a rather high helix content was detected. A cDNA encoding most of the C subunit of the V-ATPase of human brain was also cloned and sequenced. The deduced amino acid sequence of this gene is almost identical to the bovine polypeptide with only one change of tyrosine 336 that was replaced by histidine in the human gene. Two polypeptide fragments derived from subunit E of V-ATPase from chromaffin granules were sequenced and found to be identical to the predicted amino acid sequence ...
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Pomegranate (Punica granatum) is an edible fruit originating in the Middle East, the juice of which is widely available commercially. Various parts of the fruit including the juice have been used traditionally to treat a range of ailments.. The juice and other extracts have shown a wide range of bioactivity in pre-clinical studies, such as anti-inflammatory, anti-infective and anti-oxidant effects.. On the basis of this research, beneficial effects are claimed in cancer, specifically in the prevention and treatment of prostate cancer.. Few clinical trials in cancer have been conducted to date: an uncontrolled trial showed promising beneficial effects on prostate specific antigen (PSA) doubling time in prostate cancer but subsequent randomised controlled trials have failed to show any difference between pomegranate and placebo. One small randomized clinical trial did not show an effect of pomegranate consumption on breast cancer risk.. Pomegranate juice has been widely consumed for many years. It ...
Cultures of bovine adrenomedullary chromaffin cells accumulated 1-methyl-4-phenylpyridinium (MPP+) in a time- and concentration-dependent manner by a process that was prevented by desmethylimipramine. The subcellular localization of the incorporated [methyl-3H]MPP+ was examined by differential centrifugation and sucrose density gradient fractionation and was found to be predominantly colocalized with catecholamines in chromaffin vesicles, and negligible amounts were detected within the mitochondrial fraction. When chromaffin cell membranes were made permeable with the detergent digitonin in the absence of calcium, there was no increase in the release of [3H]MPP+, indicating that there is negligible accumulation of the neurotoxin in the cytosol. Simultaneous exposure to digitonin and calcium induced cosecretion of MPP+ and catecholamines. Stimulation of the cells with nicotine released both catecholamines and MPP+ at identical rates and percentages of cellular content in a calcium-dependent ...
In addition to the canonical ribonucleoside and deoxyribonucleoside phosphates and cofactors, cells contain a large number of minor nucleotides. Among these are the diadenosine polyphosphates (ApnA, where n = 2-7 [1]). Ap3A and Ap4A are the most intensively studied of these and are generally present in the soluble fraction of eukaryotic and prokaryotic cells at concentrations between 10 nM and 5 μM [2]. Platelet dense granules, adrenal chromaffin granules and certain synaptic vesicles have been reported to contain high concentrations of Ap5A and Ap6A in addition to Ap3A and Ap4A, all of which can be exocytosed following appropriate stimuli and bind to target cell purinoceptors causing a variety of physiological responses in the cardiovascular and central and peripheral nervous systems [1, 3-5]. However, although Ap6A has been detected in erythrocytes [6], there are no substantiated measurements of Ap5A and Ap6A in the soluble fraction of nucleated cells, and it is likely that they are typically ...
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Dopamine beta-monooxygenase is shown to catalyze the oxidation of N,N,N,N-tetramethyl-1,4-phenylenediamine (TMPD) to its cation radical in the presence of a regular substrate and molecular oxygen. The enzyme-mediated oxidation of TMPD is stoichiometrically coupled with the hydoxylation of the substrate to the corresponding enzymatic product. TMPD is kinetically well behaved as an alternate electron donor for the enzyme with a potency comparable to that of the most efficient electron donor, ascorbate. Dopamine beta-monooxygenase mediated oxidation of TMPD has been employed to design a convenient and sensitive spectrophotometric assay for the enzyme. The finding that TMPD is a well behaved facile alternate electron donor for dopamine beta-monooxygenase raises some interesting novel questions regarding the specificity and chemistry of the reduction site, which may have important implications on the reduction of active site coppers of the enzyme ...
TY - JOUR. T1 - Microsequencing of dopamine beta-monooxygenase. AU - McCafferty, B.. AU - Angeletti, R. H.. PY - 1987. Y1 - 1987. N2 - Tryptic peptides and cyanogen bromide fragments of dopamine beta-monooxygenase (DBH) were prepared and separated on C-8 reverse phase columns by high pressure liquid chromatography. Absorbance profiles at both 220 nm and 280 nm were monitored so that peptides with aromatic residues could be isolated. These peptides were subjected to automated Edmann degradation with a gas phase microsequencer.. AB - Tryptic peptides and cyanogen bromide fragments of dopamine beta-monooxygenase (DBH) were prepared and separated on C-8 reverse phase columns by high pressure liquid chromatography. Absorbance profiles at both 220 nm and 280 nm were monitored so that peptides with aromatic residues could be isolated. These peptides were subjected to automated Edmann degradation with a gas phase microsequencer.. UR - ...
Rat pheochromocytoma cells (PC 12) permeabilized with staphylococcal α-toxin release [3H]dopamine after addition of micromolar Ca2+. This does not require additional Mg2+-ATP (in contrast to bovine adrenal medullary chromaffin cells). We also observed Ca2+-dependent [3H]-dopamine release from digitonin-permeabilized PC 12 cells. Permeabilization with α-toxin or digitonin and stimulation of the cells were done consecutively to wash out endogenous Mg2+-ATP. During permeabilization, ATP was removed effectively from the cytoplasm by both agents but the cells released [3H]dopamine in response to micromolar Ca2+ alone. Replacement by chloride of glutamate, which could sustain mitochondrial ATP production in permeabilized cells, does not significantly alter catecholamine release induced by Ca2+. However, Mg2+ without ATP augments the Ca2+-induced release. The release was unaltered by thiol-, hydroxyl-, or calmodulin-interfering substances. Thus Mg2+-ATP, calmodulin, or proteins containing -SH or -OH ...
Catecholamine secretion in the bovine adrenal medulla is evoked largely by nicotinic receptor activation. However, bovine adrenal medulla also contain muscarini
Definition of chromaffin cell in the Financial Dictionary - by Free online English dictionary and encyclopedia. What is chromaffin cell? Meaning of chromaffin cell as a finance term. What does chromaffin cell mean in finance?
Definition of Chromaffin cells in the Legal Dictionary - by Free online English dictionary and encyclopedia. What is Chromaffin cells? Meaning of Chromaffin cells as a legal term. What does Chromaffin cells mean in law?
Buy BAM (8-22) (Bovine Adrenal Medulla 8-22) (CAS 412961-36-5), a water soluble SNSR agonist. Join researchers using high quality BAM (8-22) (Bovine Adrenal…
DBH - Rabbit polyclonal antibody to Dopamine beta-Hydroxylase (dopamine beta-hydroxylase (dopamine beta-monooxygenase)) available from OriGene
Dopamine beta-hydroxylase (DBH; dopamine beta-monooxygenase) is a copper-containing glycoprotein consisting of four identical subunits and catalyzes the oxidation of dopamine to norepinephrine. It requires ascorbic acid as an electron donor. DBH is localized in the norepinephrinergic and epinephrinergic neurons in the central nervous system. The enzyme exists in the secretory vesicles as both soluble and membrane-bound forms. The soluble form is secreted with catecholamines by exocytosis whereas the membrane-bound form is recycled into the vesicles ...
Dopamine beta-hydroxylase (DBH; dopamine beta-monooxygenase) is a copper-containing glycoprotein consisting of four identical subunits and catalyzes the oxidation of dopamine to norepinephrine. It requires ascorbic acid as an electron donor. DBH is localized in the norepinephrinergic and epinephrinergic neurons in the central nervous system. The enzyme exists in the secretory vesicles as both soluble and membrane-bound forms. The soluble form is secreted with catecholamines by exocytosis whereas the membrane-bound form is recycled into the vesicles ...
Patient information for EPILIM CHRONOSPHERE 500MG MODIFIED RELEASE GRANULES Including dosage instructions and possible side effects.
Investigations into the effects of culturing bovine adrenal chromaffin cells in the presence (72 h) of dibutyryl cyclic AMP, forskolin, and reserpine on the level and release of [Met]enkephalyl-Arg6-Phe7 immunoreactivity, noradrenaline, and adrenaline are reported. The assay for [Met]enkephalyl-Arg6-Phe7 immunoreactivity recognises both peptide B, the 31-amino acid carboxy-terminal segment of proenkephalin, and its heptapeptide fragment, [Met]enkephalyl-Arg6-Phe7. Treatments that elevate cyclic AMP increase the amount of peptide immunoreactivity in these cells; this is predominantly peptide B-like immunoreactivity in both control cells and cyclic AMP-elevated cells. Treatment with reserpine gives no change in total immunoreactivity levels, but does not result in increased accumulation of the heptapeptide [Met]enkephalyl-Arg6-Phe7 at the expense of immunoreactivity that elutes with its immediate precursor, peptide B. Cyclic AMP treatment causes either no change or a decrease in levels of accumulated
TY - JOUR. T1 - Recapture after exocytosis causes differential retention of protein in granules of bovine chromaffin cells. AU - Perrais, David. AU - Kleppe, Ingo C.. AU - Taraska, Justin W.. AU - Almers, Wolfhard. PY - 2004/10/15. Y1 - 2004/10/15. N2 - After exocytosis, chromaffin granules release essentially all their catecholamines in small fractions of a second, but it is unknown how fast they release stored peptides and proteins. Here we compare the exocytic release of fluorescently labelled neuropeptide Y (NPY) and tissue plasminogen activator from single granules. Exocytosis was tracked by measuring the membrane capacitance, and single granules in live cells were imaged by evanescent field microscopy. Neuropeptide Y left most granules in small fractions of a second, while tissue plasminogen activator remained in open granules for minutes. Taking advantage of the dependence on pH of the fluorescence of green fluorescent protein, we used rhythmic external acidification to determine whether ...
Adrenal chromaffin cells (ACCs) secrete several neuroactive substances that are effective in influencing pain sensitivity in the central nervous system as well as enhancing the recovery of the intrinsic nigrostriatal dopaminergic system in patients w
The vesicular monoamine transporter acts to accumulate cytosolic monoamines into vesicles, using the proton gradient maintained across the vesicular membrane. Its proper function is essential to the correct activity of the monoaminergic systems that have been implicated in several human neuropsychiatric disorders. The transporter is a site of action of important drugs, including reserpine and tetrabenazine (Peter et al., 1993 [PubMed 7905859]). See also SLC18A2 (MIM 193001).[supplied by OMIM, Mar 2008 ...
In general, DA, after its synthesis, is taken up and stored in specialized subcellular organelles, the storage granules, to ensure its regulated release via exocytosis. Most information about the granular transport mechanism(s) and storage mechanism(s) of DA (and monoamines in general) has been obtained by using chromaffin granules isolated from adrenal medullary cells or PC12 cells as experimental substrate (Roda et al., 1980). Thus, it is presently known that the DAergic granular transport system consists of at least two components: (1) a so-called vesicular monoamine transporter (VMAT), structurally distinct from the plasma membrane DA transporter, and (2) a vacuolar-type ATP-driven H+ pump, which provides the electrochemical gradient on which the transporter depends for its function (Johnson, 1988; Schuldiner, 1994). Drugs such as reserpine and tetrabenazine deplete intracellular DA stores by selectively interfering with transmitter uptake via the VMAT. In the present set of experiments, we ...
A chromophil biological cell is a cell which is easily stainable by absorbing chromium salts used in histology to increase the visual contrast of samples for microscopy. Chromophil cells are mostly hormone-producing cells containing so-called chromaffin granules. In these subcellular structures, amino acid precursors to certain hormones are accumulated and subsequently decarboxylated to the corresponding amines, for example epinephrine, norepinephrine, dopamine or serotonin. Chromophil cells therefore belong to the group of APUD (amine precursor uptake and decarboxylation) cells. These cells are scattered throughout the whole body, but particularly in glands such as the hypothalamus, hypophysis, thyroid, parathyroid and pancreas ...
A process for making coated detergent granules by producing detergent granules and then uniformly distributing finely divided powder onto the surfaces of the detergent granules by means of an electrostatic charging and delivery system. The detergent granules are preferably glutinous (hot and/or sticky) and freely falling during application of the electrostatically charged powder particles. Detergent granules made according to this process are also covered.
TY - JOUR. T1 - Cloning and sequence analysis of cDNA for bovine carboxypeptidase E. AU - Fricker, Lloyd D.. AU - Evans, Chris J.. AU - Esch, Fred S.. AU - Herbert, Edward. PY - 1986/12/1. Y1 - 1986/12/1. N2 - Carboxypeptidase E (enkephalin convertase) was first identified as the carboxypeptidase B-like enzyme involved in the biosynthesis of enkephalin in bovine adrenal chromaffin granules1. A similar enzyme is present in many brain regions1,2 and in purified secretory granules from rat pituitary3 and rat insulinoma4. Within the secretory granules, carboxypeptidase E (CPE) activity is found in both a soluble and a membrane-bound form1, which differ slightly in relative molecular mass (Mr)5. Here, to investigate whether the CPE activities in the various tissues are produced from a single gene, purified CPE was partially sequenced and oligonucleotide probes were used to isolate a clone encoding CPE from a bovine pituitary complementary DNA library. This cDNA hybridizes to bovine pituitary poly(A)+ ...
TY - JOUR. T1 - Sodium-azide-evoked noradrenaline and catecholamine release from peripheral sympathetic nerves and chromaffin cells. AU - Török, Tamás L.. AU - Pauló, Tünde. AU - Tóth, Péter T.. AU - Azzidani, Awad M.. AU - Powis, David A.. AU - Magyar, K.. PY - 1989. Y1 - 1989. N2 - 1. 1. The spontaneous release of [3H]noradrenaline ([3H]NA) has been measured from rabbit pulmonary arteries and bovine chromaffin cells in the presence of neuronal uptake blocker cocaine (3 × 10-5 M). 2. 2. The Na+-pump inhibitor sodium-azide (NaN3, 2 mM) produced a moderate increase of [3H]NA release from both preparations and relaxed the arteries. The [3H]releasing action of NaN3 was accompanied by a 30% inhibition of 86Rb-uptake into chromaffin cells. 3. 3. In both preparations, ouabain (10-4 M) markedly increased the release of [3H], contracted the arteries and inhibited the 86Rb-uptake of chromaffin cells by about 75%. A combined application of NaN3 and ouabain produced a similar inhibition of ...
Common Functional Genetic Variants in Catecholamine Storage Vesicle Protein Promoter Motifs Interact to Trigger Systemic Hypertension Academic Article ...
Author: Nili, U. et al.; Genre: Journal Article; Published in Print: 2006-12-01; Title: Munc18-1 phosphorylation by protein kinase C potentiates vesicle pool replenishment in bovine chromaffin cells
Background: Hypertension is a complex trait, with deranged autonomic control of circulation. Chromogranin B (CHGB) is the most abundant core protein in human catecholamine secretory vesicles, playing an important role in their biogenesis. Does common interindividual variation at the CHGB locus contribute to phenotypic variation in CHGB and catecholamine secretion, autonomic stability of circulation, or blood pressure (BP) in the population? Methods and Results: To probe interindividual variability in CHGB, we systematically studied polymorphism across the locus by resequencing CHGB (≈6 kbp footprint spanning the promoter, 5 exons, exon/intron borders, untranslated regions) in 160 subjects (2n=320 chromosomes) of diverse biogeographic ancestries. We identified 53 single-nucleotide polymorphisms, of which 22 were common. We then studied 1182 subjects drawn from the most extreme BP values in the population (highest and lowest 5th percentiles), typing 4 common polymorphisms spanning the ≈14 kbp ...
The sympathetic nervous system is activated by a variety of threats to organismal homeostasis. The adrenomedullary chromaffin cell is the core effector of sympathetic activity in the peripheral nervous system. By design, the chromaffin cell secretory response is mutable so that release can be rapidly tuned to drive context-dependent changes in physiological function. However, the mechanisms by which this tuning is achieved with such high temporal fidelity and context specificity remain unclear. This represents a major gap in our understanding of the sympatho-adrenal system since it is known to modify the function of nearly every organ system in the body. In chromaffin cells, the trigger for stimulus-evoked exocytosis is a rise in intracellular Ca2+. The level of intracellular Ca2+ accumulation varies with the stimulus intensity and secretagogue. Ca2+ regulates release by acting on the Ca2+-binding synaptotagmin (Syt) protein family, driving their penetration into membranes that harbor anionic lipids,
A case-control study of 959 prevalent cases of parkinsonism (767 with PD) and 1989 controls across five European centres. Mucin gene mRNA levels in broilers challenged with eimeria and/or Clostridium perfringens. The bootstrapping procedure indicated that the parameter estimates were very stable, thus lending greater credence to the model.. These data provide a reference for the Y-STR database in Jilin Province, and they may be valuable for population genetic analysis. Ten-year experience using a plastic, disposable curette for the diagnosis of primary ciliary dyskinesia. Of the eight patients with Stage II-III disease, six patients eventually died of metastatic disease despite additional radiotherapy and/or chemotherapy.. These data provide important new insight into augmentin bambini the molecular mechanisms of apoptosis resistance in co-stimulated T cells. In chromaffin cells, ARF6 is specifically associated with the membrane of secretory chromaffin granules. Analysis of the complete ...
18 Adrenaline and noradrenaline: Most of the synthesis occurs in the adrenergic nerve ending and stored in granular vesicles called chromaffin granules close to the site of release into synaptic cleft . Biosynthesis could also occur in suprarenal medulla and other tissues. The enzyme (N-methyl transferase) which catalyses the conversion of noradrenaline to adrenaline occurs almost exclusively in suprarenal medulla and is therefore missing in the peripheral nerve terminals. Hence noradrenaline is the final step in the synthetic process in most adrenergic nerves. Catecholamines are sympathomimetics that contain the catechol nucleus (e.g. noradrenaline and adrenaline). Catecholamines are stored in synaptic granules in two forms in equilibrium: Bound noradrenaline with ATP and protein is the (inactive part). Free noradrenaline is released by nerve stimulation. Another portion of it is stored in the cytoplasm in free form (cytoplasmic free noradrenaline). ...
Synonyms for adrenomedullary hormones in Free Thesaurus. Antonyms for adrenomedullary hormones. 2 synonyms for hormone: endocrine, internal secretion. What are synonyms for adrenomedullary hormones?
Area of interest: Mechanisms of stress transduction at the sympatho-adrenal synapse; optical studies of hormone trafficking and secretion in the adrenomedullary chromaffin cell.
Shelly carbonate sands represent an extreme soil type in terms of their mechanical behavior which derives from the bioclastic nature of the constituent grains. In their uncemented form, these deposits exhibit very high compressibility, which has posed a number of geotechnical engineering problems; in most cases related to the reduction in the bearing capacities of both shallow and deep foundations. Remarkable features of these carbonate sands include the complex shape and the structural weakness of the grains and the high inter and intra granular porosity. Previous studies, have quoted the interlocking of the angular shelly particles to be at the origin of their high friction angles and high initial void ratio, however, up until now, no scientific micro-scale examination has been carried out. This paper presents a non-invasive image based investigation into the grain morphology of a carbonate sand from the Persian Gulf. This sand has a median grain size of 570μm and a high CaCO3 content in the ...
Nili, U.; de Wit, H.; Gulyas-Kovacs, A.; Toonen, R. F.; Soerensen, J. B.; Verhage, M.; Ashery, U.: Munc18-1 phosphorylation by protein kinase C potentiates vesicle pool replenishment in bovine chromaffin cells. Neuroscience 143 (2), pp. 487 - 500 (2006 ...
Reactome is pathway database which provides intuitive bioinformatics tools for the visualisation, interpretation and analysis of pathway knowledge.
Reactome is pathway database which provides intuitive bioinformatics tools for the visualisation, interpretation and analysis of pathway knowledge.
The present application relates to a steam treated pelletized feed composition comprising a granule comprising a core and a coating wherein the core comprises an active compound and the coating comprises a salt.
Synaptotagmin-1, the canonical isoform of the synaptotagmin family, is a Ca(2+) sensor for fast synchronous neurotransmitter release in forebrain neurons and chromaffin cells. Even though deletion of synaptotagmin-1 abolishes fast exocytosis in chromaffin cells, it reduces overall secretion by only 20% because of the persistence of slow exocytosis. Therefore, another Ca(2+) sensor dominates release in these cells. Synaptotagmin-7 has a higher Ca(2+) affinity and slower binding kinetics than synaptotagmin-1, matching the proposed properties for the second, slower Ca(2+) sensor. Here, we examined Ca(2+)-triggered exocytosis in chromaffin cells from KO mice lacking synaptotagmin-7, and from knockin mice containing normal levels of a mutant synaptotagmin-7 whose C(2)B domain does not bind Ca(2+). In both types of mutant chromaffin cells, Ca(2+)-triggered exocytosis was decreased dramatically. Moreover, in chromaffin cells lacking both synaptotagmin-1 and -7, only a very slow release component, ...
The ACh-stimulated increase in [Ca2+]i in bovine adrenal chromaffin cells is mainly triggered by an influx of Ca2+ through the nAChR channel, VOC, and the subsequent activation of Ca2+-induced Ca2+ release, all of which contribute to CA release. These events in response to ACh are of short duration, whereas PACAP induces large and sustained increases in [Ca2+]i and CA release. The present study sought to elucidate which pathways (nAChR channel, VOC, SOC, or an unidentified channel) contribute to this peculiar Ca2+ and secretory response to PACAP.. Reports vary concerning the effect of VOC blockers on PACAP-induced rise in [Ca2+]i and CA release. For example, Przywara et al. (1996) showed that in rat cultured adrenal chromaffin cells, neither L- nor N-type VOC participates in the PACAP-induced CA release. On the other hand,Fukushima et al. (2001b) showed that nifedipine, L-type VOC antagonist, reduced PACAP-induced CA release in isolated perfused rat adrenal gland. Tanaka et al. (1996) reported ...
S. Karanth, W. H. Yu, A. Walczewska, C. Mastronardi, S. M. McCann, Ascorbic acid acts as an inhibitory transmitter in the hypothalamus to inhibit stimulated luteinizing hormone-releasing hormone release by scavenging nitric oxide, Proceedings of the National Academy of Sciences, 2000, 97, 4, ...
Adrenal chromaffin cells are excitable neuroendocrine cells that have been widely used as a simple model of neurosecretion. In vivo, acetylcholine released from preganglionic neurons binds to nicotinic receptors, which are Na+ ionophores, causing Na+ influx that depolarizes the plasma membrane. Depolarization in turn causes voltage-gated calcium channels (VGCCs) to open, leading to an influx of Ca2+ that activates the fusion of secretory granules with the plasma membrane, resulting in catecholamine release that occurs within milliseconds. This Ca2+-dependent secretory process is referred to as exocytosis. Previous investigations exploring the potential for nanosecond electric pulses (NEPs) to serve as a novel bioelectric stimulus of neurosecretion in chromaffin cells have shown that in chromaffin cells exposed to 5 ns, 5 MV/m electric pulses, catecholamine release is stimulated in a manner that relies on Ca2+ influx via VGCCs. The goal of the present study was to further understand this novel ...
Chromaffin cells are neuroendocrine cells found predominantly in the medulla of the adrenal gland. They are also found in other ganglia of the sympathetic nervous system and are derived from the embryonic neural crest. Embryology They arise in ...
The properties of Ca(2+)- and voltage-dependent K+ currents and their role in defining membrane potential were studied in cultured rat chromaffin cells. Two variants of large-conductance, Ca2+ and voltage-dependent BK channels, one noninactivating and one inactivating, were largely segregated among patches. Whole-cell noninactivating and inactivating currents resulting from each of these channels were segregated among different chromaffin cells. Cell-to-cell variation in the rate and extent of whole-cell current decay was not explained by differences in cytosolic [Ca2+] regulation among cells; rather, variation was due to differences in the intrinsic properties of the underlying BK channels. About 75% of rat chromaffin cells and patches express inactivating BK current (termed BKi) while the remainder express noninactivating BK current (termed BKs). The activation time course of both currents is similar, as is the dependence of activation on [Ca2+] and membrane potential. However, deactivation of ...
The differentiation of neuronal cell progenitors depends on complex interactions between intrinsic cellular programs and environmental cues. Such interactions have recently been explored using an immortalized sympathoadrenal progenitor cell line, MAH. These studies have revealed that depolarizing conditions, in combination with exposure to FGF, can induce responsiveness to NGF. Here we report that CNTF, which utilizes an intracellular signaling pathway distinct from that of both FGF and NGF, can collaborate with FGF to promote efficiently the differentiation of MAH progenitor cells to a stage remarkably reminiscent of NGF-dependent, postmitotic sympathetic neurons. We also find that similar collaborative interactions can occur during transdifferentiation of normal cultured chromaffin cells into sympathetic neurons ...
Doxycycline synthroid. In most instances, the biopsy is taken from the actual tumor. Chlorpromazine was with- drawn and doxycycline synthroid substituted (up to a maximum of 600 mgday). Chronic morphine increases levels synthrodi types I (ACI) and VIII (ACVIII) adenylyl cyclase, PKA catalytic (C) and regulatory type II (RII) subunits, and several phosphoproteins, including CREB and tyrosine hydroxylase (TH), the rate-limiting enzyme in norepinephrine biosynthesis.