Relationship between dog saphenous vein reactivity and Na content

1988 ◽  
Vol 255 (4) ◽  
pp. H860-H865
Author(s):  
V. Berczi ◽  
G. Simon
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Saphenous Vein ◽  
Dna Content ◽  
Mode Of Action ◽  
Venous Blood ◽  
Dog Saphenous Vein ◽  
Wide Range ◽  
Venous Wall ◽  
Stimulation Of

The physiological significance of the wide range of spontaneous variation in the total Na content of the dog saphenous vein (SV) was investigated. The SV of pentobarbital-anesthetized male mongrel dogs was perfused in vitro with the dogs' own venous blood, and its reactivity to acetylcholine (ACh) and norepinephrine (NE) was measured. The contralateral SV was removed for measurements of total and intracellular (Li exchange at 4 degrees C) Na and K content, DNA content, and muscle width. Reactivity to ACh correlated directly with total and extracellular SV Na content, and reactivity to NE correlated directly with total and intracellular K content. Reactivity to NE was unrelated to ACh reactivity, plasma NE concentration, or venous wall DNA content or muscle width. ACh-mediated venoconstriction was approximately 10 times more sensitive to inhibition by amiloride, an inhibitor of Na-entry pathways, than NE-mediated venoconstriction. The finding that extracellular Na content is a marker of reactivity to ACh is compatible with experimental evidence that the mode of action of ACh may be the stimulation of Na influx. The positive correlation between the K content and reactivity of veins to NE suggests that there is a link between intracellular K content and the release of Ca from the sarcoplasmic reticulum in response to NE.

Effects of endogenous calcium transport inhibitor from heart muscle on the active calcium uptake and passive calcium release properties of sarcoplasmic reticulum

1989 ◽  
Vol 67 (9) ◽  
pp. 999-1006 ◽  
Author(s):  
Njanoor Narayanan ◽  
Philip Bedard ◽  
Trilochan S. Waraich
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Heart Muscle ◽  
Calcium Release ◽  
Membrane Vesicles ◽  
Transport Inhibitor ◽  
Low Concentrations ◽  
Active Calcium ◽  
High Concentrations ◽  
Stimulation Of

In the present study, the effects of the cytosolic Ca2+ transport inhibitor on ATP-dependent Ca2+ uptake by, and unidirectional passive Ca2+ release from, sarcoplassmic reticulum enriched membrane vesicles were examined in parallel experiments to determine whether inhibitor-mediated enhancement in Ca2+ efflux contributes to inhibition of net Ca2+ uptake. When assays were performed at pH 6.8 in the presence of oxalate, low concentrations (<100 μg/mL) of the inhibitor caused substantial inhibition of Ca2+ uptake by SR (28–50%). At this pH, low concentrations of the inhibitor did not cause enhancement of passive Ca2+ release from actively Ca2+-loaded sarcoplasmic reticulum. Under these conditions, high concentrations (>100 μg/mL) of the inhibitor caused stimulation of passive Ca2+ release but to a much lesser extent when compared with the extent of inhibition of active Ca2+ uptake (i.e., twofold greater inhibition of Ca2+ uptake than stimulation of Ca2+ release). When Ca2+ uptake and release assays were carried out at pH 7.4, the Ca2+ release promoting action of the inhibitor became more pronounced, such that the magnitude of enhancement in Ca2+ release at varying concentrations of the inhibitor (20–200 μg/mL) was not markedly different from the magnitude of inhibition of Ca2+ uptake. In the absence of oxalate in the assay medium, inhibition of Ca2+ uptake was observed at alkaline but not acidic pH. These findings imply that the inhibition of Ca2+ uptake observed at pH 6.8 is mainly due to decrease in the rate of active Ca2+ transport into the membrane vesicles rather than stimulation of passive Ca2+ efflux; at alkaline pH (pH 7.4), enhanced Ca2+ efflux contributes substantially, if not exclusively, to the decrease in Ca2+ uptake observed in the presence of the inhibitor. It is suggested that if the cytosolic inhibitor has actions similar to those observed in vitro in intact cardiac muscle, acid–base status of the intracellular fluid would be a major factor influencing the nature of its effects (inhibition of Ca2+ uptake or stimulation of Ca2+ release) on transmembrane Ca2+ fluxes across the sarcoplasmic reticulum.Key words: sarcoplasmic reticulum, Ca2+ uptake, Ca2+ release, endogenous inhibitor, heart muscle.

Gastric and duodenal HCO3- transport in vitro: effects of hormones and local transmitters

1982 ◽  
Vol 242 (2) ◽  
pp. G100-G110 ◽  
Author(s):  
G. Flemstrom ◽  
J. R. Heylings ◽  
A. Garner
Keyword(s):  
Phosphodiesterase Inhibitor ◽  
Duodenal Mucosa ◽  
Dibutyryl Camp ◽  
Inhibitory Peptide ◽  
Luminal Membrane ◽  
Wide Range ◽  
In Vitro Effects ◽  
Histamine H2 Antagonists ◽  
Stimulation Of

Luminal application of acid was recently shown to stimulate surface epithelial HCO3(-) transport in stomach and duodenum. Effects of some potential transmitters of this response were therefore studied in amphibian gastric fundic and proximal duodenal mucosa in vitro. Duodenal HCO3- transport, which could be titrated directly, was stimulated by dibutyryl cAMP (DBcAMP, 10(-6) M), the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (10(-6) M), noradrenaline (10(-6) M), pancreatic glucagon (10(-8) M), and gastric inhibitory peptide (GIP, 10(-10) M). Stimulation by glucagon, but not by prostaglandin E2 (PGE2, 10(-6) M), required Cl- in the luminal solution and was prevented by furosemide (10(-3) M). This suggests that glucagon may affect HCO3(-)-Cl- exchange at the luminal membrane while transport stimulated by prostaglandins may be electrogenic. Stimulatory effects of glucagon and PGE2 were also additive. Gastric HCO3- transport, studied in tissues after inhibition of H+ secretion by histamine H2-antagonists, clearly differed from duodenum in that noradrenaline and GIP were inhibitory and DBcAMP was without effect. Stimulation of gastric HCO3- transport was observed with glucagon (10(-8) M), natural cholecystokinin (CCK, 10(-8) M), and CCK octapeptide (10(-7) M), CCK preparations had no effect in the duodenum. Although tested over a wide range of concentrations, no effect on either duodenal or gastric HCO3- transport was observed with histamine, pentagastrin, tetragastrin, urogastrone, ACTH, bombesin, motilin, secretin, serotonin, somatostatin, substance P, or vasoactive intestinal peptide.

Does in vitro activation of postsynaptic α2-adrenoceptor utilize intracellular Ca2+ for contraction in dog saphenous vein?

1989 ◽  
Vol 67 (9) ◽  
pp. 1086-1091 ◽  
Author(s):  
Y. Y. Guan ◽  
C. Y. Kwan ◽  
E. E. Daniel
Keyword(s):  
Saphenous Vein ◽  
Krebs Solution ◽  
Free Medium ◽  
High Concentration ◽  
Dog Saphenous Vein ◽  
Ph Buffering ◽  
Intracellular Ca ◽  
Muscle Calcium ◽  
Subsequent Addition

Dog saphenous vein spiral strips were employed to determine whether an intracellular source of Ca2+ is used for contraction upon activation of the α2-adrenoceptor by B-HT 920 in Ca2+-free Krebs solution containing 50 μM EGTA. The studies were carried out in parallel with the activation of the α1-adrenoceptor by phenylephrine (Phe) under the condition that B-HT 920 (10−5 M) and Phe (2 × 10−6 M) gave rise to a similar level of responses in Ca2+-containing Krebs solution. A similar level of responses to these agonists at equieffective concentrations in Ca2+-free medium were also observed. Such responses to Phe and B-HT 920 were inhibited by 10−7 M rauwolscine and 10−7 M prazosin, respectively, and were not affected by 10−7 M nifedipine or 5 mM Mn2+. The responses to B-HT 920 (10−5 M) and submaximal concentration of Phe (2 × 10−6 M) in Ca2+-free medium were additive. However, if the vascular strips were first contracted maximally with 10−4 M Phe in Ca+2-free medium to deplete the intracellular Ca store, subsequent addition of B-HT 920 failed to induce additional response. Our results strongly suggest that activation of α2-adrenoceptor in dog saphenous vein in Ca2+-free medium indeed utilizes intracellular Ca2+ for contraction. We also found that the failure of earlier studies to demonstrate the contractile effects of B-HT 920 in dog saphenous vein was due to experimental artifacts derived from the use of high concentration of EGTA and artificial pH-buffering reagent.Key words: adrenoceptor, saphenous vein, vascular muscle, calcium.

Role of calcium in metabolic signaling between cardiac sarcoplasmic reticulum and mitochondria in vitro

2003 ◽  
Vol 284 (2) ◽  
pp. C285-C293 ◽  
Author(s):  
Robert S. Balaban ◽  
Salil Bose ◽  
Stephanie A. French ◽  
Paul R. Territo
Keyword(s):  
Energy Metabolism ◽  
Sarcoplasmic Reticulum ◽  
Atp Synthesis ◽  
Cardiac Sarcoplasmic Reticulum ◽  
Atp Production ◽  
Wide Range ◽  
Reconstituted System

The role of Ca2+ as a cytosolic signaling molecule between porcine cardiac sarcoplasmic reticulum (SR) ATPase and mitochondrial ATP production was evaluated in vitro. The Ca2+ sensitivity of these processes was determined individually and in a reconstituted system with SR and mitochondria in a 0.5:1 protein-to-cytochrome aa 3 ratio. The half-maximal concentration ( K 1/2) of SR ATPase was 335 nM Ca2+. The ATP synthesis dependence was similar with a K 1/2 of 243 nM for dehydrogenases and 114 nM for overall ATP production. In the reconstituted system, Ca2+ increased thapsigargin-sensitive ATP production (maximum ∼5-fold) with minimal changes in mitochondrial reduced nicotinamide adenine dinucleotide (NADH). NADH concentration remained stable despite graded increases in NADH turnover induced over a wide range of Ca2+ concentrations (0 to ∼500 nM). These data are consistent with a balanced activation of SR ATPase and mitochondrial ATP synthesis by Ca2+ that contributes to a homeostasis of energy metabolism metabolites. It is suggested that this balanced activation by cytosolic Ca2+ is partially responsible for the minimal alteration in energy metabolism intermediates that occurs with changes in cardiac workload in vivo.

scholarly journals Venous Blood Derivatives as FBS-Substitutes for Mesenchymal Stem Cells: A Systematic Scoping Review

2017 ◽  
Vol 28 (6) ◽  
pp. 657-668 ◽  
Author(s):  
Luiz A. Chisini ◽  
Marcus C.M. Conde ◽  
Guillermo Grazioli ◽  
Alissa S. San Martin ◽  
Rodrigo Varella de Carvalho ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Scoping Review ◽  
Ex Vivo ◽  
Venous Blood ◽  
Biological Properties ◽  
Ex Vivo Expansion ◽  
Cochrane Library ◽  
Wide Range

Abstract Although the biological properties of mesenchymal stem cells (MSC) are well-characterized in vitro, MSC clinical application is still far away to be achieved, mainly due to the need of xenogeneic substances for cell expansion, such as fetal bovine serum (FBS). FBS presents risks regarding pathogens transmissions and internalization of animal’s proteins, which can unleash antigenic responses in patients after MSC implantation. A wide range of venous blood derivatives (VBD) has been reported as FBS substitutes showing promising results. Thus, the aim of this study was to conduct a systematic scoping review to analyze whether VBD are effective FBS substitutes for MSC ex vivo expansion. The search was performed in SciVerse ScopusTM, PubMed, Web of ScienceTM, BIREME, Cochrane library up to January 2016. The keywords were selected using MeSH and entry terms. Two independent reviewers scrutinized the records obtained considering specific inclusion criteria. The included studies were evaluated in accordance with a modified Arksey and O’ Malley’s framework. From 184 found studies, 90 were included. Bone marrow mesenchymal stem cells (BMMSC) were presented in most of these studies. Overall, VBD allowed for either, maintenance of MCS’s fibroblast-like morphology, high proliferation, high colony-formation ability and maintenance of multipotency. Besides. MSC expanded in VBD supplements presented higher mitogen activity than FBS. VBD seems to be excellent xeno-free serum for ex vivo expansion of mesenchymal stem cells. However, an accentuated heterogeneity was observed between the carried out protocols for VBD isolation did not allowing for direct comparisons between the included studies.

Regulation of pancreatic exocrine secretion in vitro : the action of secretagogues

1981 ◽  
Vol 296 (1080) ◽  
pp. 17-26 ◽  
Keyword(s):  
Acinar Cells ◽  
Exocrine Secretion ◽  
Mechanisms Of Action ◽  
Enzyme Secretion ◽  
Pancreatic Acinar Cells ◽  
Wide Range ◽  
Pancreatic Exocrine ◽  
Final Effect ◽  
Stimulation Of

Pancreatic acinar cells possess two functionally distinct mechanisms by which secretagogues can increase enzyme secretion. One mechanism is mediated by mobilization of cellular calcium and can be activated by any one of four different classes of receptors. The other mechanism is mediated by cyclic AMP and can be activated by either of two different classes of receptors. In addition to stimulating enzyme secretion, a secretagogue can cause potentiation of secretion, desensitization to the subsequent stimulation caused by the same or other secretagogues as well as residual stimulation of enzyme secretion. Although each class of secretagogue receptors can cause the same final effect, stimulation of enzyme secretion, the existence of multiple classes of receptors and the different mechanisms of action endow the acinar cell with a wide range of patterns of response depending on which of the several classes of receptors are activated.

scholarly journals A peptide that inhibits the mitogenic stimulation of Swiss 3T3 cells by bombesin or vasopressin

1985 ◽  
Vol 231 (3) ◽  
pp. 781-784 ◽  
Author(s):  
A N Corps ◽  
L H Rees ◽  
K D Brown
Keyword(s):  
Cell Proliferation ◽  
Synthetic Peptide ◽  
3T3 Cells ◽  
Wide Range ◽  
Vasopressin Receptors ◽  
Bombesin Receptor ◽  
Swiss 3T3 ◽  
Stimulation Of

The synthetic peptide [D-Arg1,D-Pro2,D-Trp7,9,Leu1]substance P inhibits the stimulation of DNA synthesis induced in Swiss 3T3 cells by bombesin or vasopressin, but not that induced by a wide range of other growth factors and mitogens. The stimulation induced by 10 pM-3 nM-bombesin is inhibited by 1-30 microM-antagonist in a manner consistent with competition at the bombesin receptor. The inhibition by the antagonist of the stimulation induced by vasopressin suggests a previously unrecognized interaction of the antagonist with vasopressin receptors. The antagonist should be useful in studies of cell proliferation both in vivo and in vitro.

scholarly journals Celestine blue B as a sensor for hypochlorous acid and HOCL-modified proteins registration

2019 ◽  
Vol 19 (2) ◽  
pp. 63-71
Author(s):  
Veronika E. Lutsenko ◽  
Daria V. Grigorieva ◽  
Irina V. Gorudko ◽  
Sergey N. Cherenkevich ◽  
Nikolay N. Gorbunov ◽  
...  
Keyword(s):  
Hypochlorous Acid ◽  
Fluorescent Sensor ◽  
Venous Blood ◽  
Acid Hydrazide ◽  
Myeloperoxidase Activity ◽  
Celestine Blue ◽  
Healthy Donors ◽  
Wide Range ◽  
Modified Proteins

Objective — the study of hypochlorous acid (HOCl) and its derivatives production, which catalyzed by human neutrophil myeloperoxidase, using “turn-on” fluorescent sensor — celestine blue B. Materials and methods. Neutrophils were isolated from the venous blood of healthy donors. Phorbol 12-myristate 13-acetate, N-formyl-methionyl-leucyl-phenylalanine, plant lectins, HOCl-modified proteins were used as agonists. N-acetylcysteine, 4-aminobenzoic acid hydrazide, isoniazid and ceruloplasmin were used as regulators of neutrophil myeloperoxidase activity and/or HOCl scavengers. Results. Using a wide range of agonists and inhibitors, it has been shown that celestine blue B is oxidized in vitro by HOCl and its derivatives as a result of neutrophil myeloperoxidase activity. The oxidation of celestine blue B by HOCl-modified human serum albumin (HSA-Cl) and inhibition of this process by monoclonal antibody against HSA-Cl (IgM class) was also found. Conclusion. Based on the developed method using celestine blue B, it is possible to conduct a sensitive analysis for the presence of HOCl-modified proteins (chloramines, etc.), to investigate the effect of various agonists and drugs on myeloperoxidase activity and exocytosis from the neutrophil granules.

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