The Role of Flow-Induced Contraction and Relaxation in the Regulation of Vascular Tone: Results of In Vitro Studies

The effect of erythrocytes (red blood cells, RBC) on vascular tone in the renal microcirculation was examined using the juxtamedullary nephron microvascular preparation perfused in vitro with a physiological salt solution containing 5% albumin. The basal diameters of the arcuate, interlobular, proximal, and distal afferent arterioles averaged 444 +/- 24, 74 +/- 3, 29 +/- 1, and 19 +/- 1 micron, respectively, when perfused with a cell-free solution at a pressure of 80 mmHg. The diameters of the arcuate and interlobular arteries increased by 14 +/- 4 and 13 +/- 4%, respectively, whereas the diameter of the proximal and distal portions of the afferent arterioles decreased by 7 +/- 2% when perfusion pressure was elevated from 80 to 160 mmHg. The addition of RBC to the perfusate reduced the basal diameters of interlobular and afferent arterioles by 11 +/- 4 and 15 +/- 3%, respectively. The maximal vasoconstrictor response was seen after the addition of only 1% RBC to the perfusate. Removal of platelets did not block the vasoconstrictor response to addition of RBC to the perfusate. The role of endothelium-derived relaxing factor (EDRF) in the vasoconstrictor response to RBC was studied by addition of nitric oxide synthase inhibitor, N omega-nitro-L-arginine (L-NNA, 100 microM) to the perfusate. L-NNA reduced the basal diameters of interlobular and afferent arterioles by 7 +/- 3 and 9 +/- 3%, respectively, and abolished the vasoconstrictor response to RBC. L-NNA had no effect on the pressure-diameter relationships of the preglomerular vasculature when added to perfusates already containing RBC.(ABSTRACT TRUNCATED AT 250 WORDS)

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Overview: Physiological Role of K+Channels in the Regulation of Vascular Tone

Potassium Channels in Cardiovascular Biology ◽

10.1007/978-1-4615-1303-2_22 ◽

2001 ◽

pp. 443-455

Author(s):

Joseph E. Brayden

Keyword(s):

Vascular Tone ◽

Physiological Role ◽

K Channels ◽

Regulation Of Vascular Tone

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The role of electrical field on neurons: In vitro studies

Conductive Polymers ◽

10.1201/9781315119007-13 ◽

2018 ◽

pp. 265-282

Author(s):

A. Lee Miller ◽

Huan Wang ◽

Michael J. Yaszemski ◽

Lichun Lu

Keyword(s):

In Vitro Studies ◽

Electrical Field

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Epithelial—mesenchymal tissue interactions guiding otic capsule formation: the role of the otocyst

Development ◽

10.1242/dev.97.1.1 ◽

1986 ◽

Vol 97 (1) ◽

pp. 1-24

Author(s):

Joseph R. McPhee ◽

Thomas R. Van De Water

Keyword(s):

Mouse Embryo ◽

Mouse Embryos ◽

In Vitro Studies ◽

Otic Capsule ◽

Membranous Labyrinth ◽

Capsule Formation ◽

Tissue Interactions ◽

Mesenchymal Tissue

The otocyst is the epithelial anlage of the membranous labyrinth which interacts with surrounding cephalic mesenchyme to form an otic capsule. A series of in vitro studies was performed to gain a better understanding of the epithelial—mesenchymal interactions involved in this process. Parallel series of otocyst/mesenchyme (O/M) and isolated periotic mesenchyme (M) explants provided morphological and biochemical data to define the role of the otocyst in organizing and directing formation of its cartilaginous otic capsule. Explants were made from mouse embryos ranging in age from 10 to 14 days of gestation, and organ cultured under identical conditions until the chronological equivalent of 16 days of gestation. Expression of chrondrogenesis was determined by both histology and biochemistry. The in vitro behaviour of periotic mesenchyme explanted either with or without an otocyst supports several hypotheses that explain aspects of otic capsule development. The results indicate that (a) prior to embryonic day 12 the otocyst alone is not sufficient to stimulate chondrogenesis of the otic capsule within O/M explants; (b) the otocyst acts as an inductor of capsule chondrogenesis within O/M explants between embryonic days 12 to 13; (c) isolated mesenchyme within M explants taken from 13-day-old embryos are capable of initiating in vitro chondrogenesis, but without expressing capsule morphology in the absence of the otocyst; and (d) the isolated mesenchyme of M explants obtained from 14-day-old embryos expresses both chondrogenesis and otic capsule morphology in the absence of the otocyst. These findings suggest that the otocyst acts as an inductor of chondrogenesis of periotic mesenchyme tissue between embryonic days 11 to 13, and controls capsular morphogenesis between embryonic days 13 to 14 in the mouse embryo.

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A critical role of VLA-4 in erythropoiesis in vivo

Blood ◽

10.1182/blood.v87.6.2513.bloodjournal8762513 ◽

1996 ◽

Vol 87 (6) ◽

pp. 2513-2517 ◽

Cited By ~ 54

Author(s):

K Hamamura ◽

H Matsuda ◽

Y Takeuchi ◽

S Habu ◽

H Yagita ◽

...

Keyword(s):

Monoclonal Antibody ◽

Fetal Liver ◽

Critical Role ◽

In Utero ◽

In Vitro Studies ◽

Specific Interactions ◽

Erythroid Progenitors

Hematopoiesis requires specific interactions with the microenvironments, and VLA-4 has been implicated in these interactions based on in vitro studies. To study the role of VLA-4 in hematopoiesis in vivo, we performed in utero treatment of mice with an anti-VLA-4 monoclonal antibody. Although all hematopoietic cells in fetal liver expressed VLA-4, the treatment specifically induced anemia. It had no effect on the development of nonerythroid lineage cells, including lymphoids and myeloids. In the treated liver almost no erythroblast was detected, whereas the erythroid progenitors, which give rise to erythroid colonies in vitro, were present. These results indicate that VLA-4 plays a critical role in erythropoiesis, while it is not critical in lymphopoiesis in vivo.

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THE ROLE OF ENDO-1,4-BETA-GLUCANASE IN PLANT CELL ELONGATION. IN-VITRO STUDIES OF PEACH POLLEN

Acta Horticulturae ◽

10.17660/actahortic.1993.329.48 ◽

1993 ◽

pp. 225-227

Author(s):

O. Shoseyov ◽

M. Dekel-Reichenbach

Keyword(s):

Plant Cell ◽

Cell Elongation ◽

In Vitro Studies ◽

Beta Glucanase

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Influence of SIN-1 on Platelet Ca2+ Handling in Patients with Suspected Coronary Artery Disease: Ex Vivo and In Vitro Studies

Thrombosis and Haemostasis ◽

10.1055/s-0037-1613904 ◽

2000 ◽

Vol 83 (05) ◽

pp. 752-758 ◽

Cited By ~ 3

Author(s):

Claude Le Feuvre ◽

Annie Brunet ◽

Thuc Do Pham ◽

Jean-Philippe Metzger ◽

André Vacheron ◽

...

Keyword(s):

Superoxide Anion ◽

Vascular Tone ◽

Ex Vivo ◽

Suspected Coronary Artery Disease ◽

In Vitro Studies ◽

H2o2 Formation ◽

Artery Disease ◽

Dose Dependent

SummaryThe 3-morpholinosydnonimine (SIN-1) generates both nitric oxide (NO) and superoxide anion (O2−). It elicits dose-dependent vasodilation in vivo, in spite of the opposite effects of its breakdown products on vascular tone and platelet aggregation.This study was designed to investigate the influence of intravenous SIN-1 injection on platelet Ca2+ handling in patients undergoing coronary angiography. SIN-1 administration reduced cytosolic [Ca2+] in unstimulated platelets by decreasing Ca2+ influx. It attenuated Ca2+ mobilization from internal stores evoked by thrombin or thapsigargin. In vitro studies were used as an approach to investigate how simultaneous productions of NO and O2− from SIN-1 modify thrombin- or thapsigargin-induced platelet Ca2+ mobilization. Superoxide dismutase, the O2− scavenger, enhanced the capacity of SIN-1 to inhibit Ca2+ mobilization but catalase had no effect.This suggests that the effects of SIN-1 on platelet Ca2+ handling resemble those of NO, but are modulated by simultaneous O2− release, independently of H2O2 formation.

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Role of A1 adenosine receptors in regulation of vascular tone

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00684.2004 ◽

2005 ◽

Vol 288 (3) ◽

pp. H1411-H1416 ◽

Cited By ~ 64

Author(s):

Huda E. Tawfik ◽

J. Schnermann ◽

Peter J. Oldenburg ◽

S. Jamal Mustafa

Keyword(s):

Adenosine Receptors ◽

Vascular Tone ◽

Receptor Subtypes ◽

Vascular Relaxation ◽

Response Curves ◽

Cgs 21680 ◽

A1 Adenosine Receptors ◽

The Impact ◽

Regulation Of Vascular Tone

The vascular response to adenosine and its analogs is mediated by four adenosine receptors (ARs), namely, A1, A2A, A2B, and A3. A2AARs and/or A2BARs are involved in adenosine-mediated vascular relaxation of coronary and aortic beds. However, the role of A1ARs in the regulation of vascular tone is less well substantiated. The aim of this study was to determine the role of A1ARs in adenosine-mediated regulation of vascular tone. A1AR-knockout [A1AR(−/−)] mice and available pharmacological tools were used to elucidate the function of A1ARs and the impact of these receptors on the regulation of vascular tone. Isolated aortic rings from A1AR(−/−) and wild-type [A1AR(+/+)] mice were precontracted with phenylephrine, and concentration-response curves for adenosine and its analogs, 5′- N-ethyl-carboxamidoadenosine (NECA, nonselective), 2-chloro- N6-cyclopentyladenosine (CCPA, A1AR selective), 2-(2-carboxyethyl)phenethyl amino-5′- N-ethylcarboxamido-adenosine (CGS-21680, A2A selective), and 2-chloro- N6-3-iodobenzyladenosine-5′- N-methyluronamide (Cl-IBMECA, A3 selective) were obtained to determine relaxation. Adenosine and NECA (0.1 μM) caused small contractions of 13.9 ± 3.0 and 16.4 ± 6.4%, respectively, and CCPA at 0.1 and 1.0 μM caused contractions of 30.8 ± 4.3 and 28.1 ± 3.9%, respectively, in A1AR(+/+) rings. NECA- and CCPA-induced contractions were eliminated by 100 nM of 1,3-dipropyl-8-cyclopentylxanthine (DPCPX, selective A1AR antagonist). Adenosine, NECA, and CGS-21680 produced an increase in maximal relaxation in A1AR(−/−) compared with A1AR(+/+) rings, whereas Cl-IBMECA did not produce contraction in either A1AR(+/+) or A1AR(−/−) rings. CCPA-induced contraction at 1.0 μM was eliminated by the PLC inhibitor U-73122. These data suggest that activation of A1ARs causes contraction of vascular smooth muscle through PLC pathways and negatively modulates the vascular relaxation mediated by other adenosine receptor subtypes.

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