Myogenic Responses in Exercise Hyperemia1

2015 ◽  
pp. 187-192 ◽  
Author(s):  
Harvey V. Sparks ◽  
Robert D. Phair
Keyword(s):  
Myogenic Responses

Myogenic reactivity is reduced in small renal arteries isolated from relaxin-treated rats

2002 ◽  
Vol 283 (2) ◽  
pp. R349-R355 ◽  
Author(s):  
Jacqueline Novak ◽  
Rolando J. J. Ramirez ◽  
Robin E. Gandley ◽  
O. David Sherwood ◽  
Kirk P. Conrad
Keyword(s):  
Nitric Oxide ◽  
Virgin Female ◽  
Renal Arteries ◽  
Mesenteric Arteries ◽  
Blood Levels ◽  
Renal Circulation ◽  
Nitric Oxide Synthase Inhibitor ◽  
Myogenic Responses ◽  
Synthase Inhibitor ◽  
Oxide Synthase

Administration of the ovarian hormone relaxin to nonpregnant rats vasodilates the renal circulation comparable to pregnancy. This vasodilation is mediated by endothelin (ET), the ETB receptor, and nitric oxide. Furthermore, endogenous relaxin mediates the renal vasodilation and hyperfiltration that occur during gestation. The goal of this study was to investigate whether myogenic reactivity of small renal and mesenteric arteries is reduced in relaxin-treated rats comparable to the pregnant condition. Relaxin or vehicle was administered to virgin female Long-Evans rats for 5 days at 4 μg/h, thereby producing midgestational blood levels of the hormone. The myogenic responses of small renal arteries (200–300 μm in diameter) isolated from these animals were evaluated in an isobaric arteriograph system. Myogenic reactivity was significantly reduced in the small renal arteries from relaxin-treated compared with vehicle-treated rats. The reduced myogenic responses were mediated by the ETB receptor and nitric oxide since the selective ETB receptor antagonist RES-701–1 and the nitric oxide synthase inhibitor N G-nitro-l-arginine methyl ester restored myogenic reactivity to virgin levels. The influence of relaxin was not limited to the renal circulation because myogenic reactivity was also reduced in small mesenteric arteries isolated from relaxin-treated rats. Thus relaxin administration to nonpregnant rats mimics pregnancy, insofar as myogenic reactivity of small renal and mesenteric arteries is reduced in both conditions.

Myogenic responses of isolated adipose tissue arterioles

2003 ◽  
Vol 66 (2) ◽  
pp. 140-146 ◽  
Author(s):  
Samir S Undavia ◽  
Valentina Berger ◽  
Gabor Kaley ◽  
Edward J Messina
Keyword(s):  
Adipose Tissue ◽  
Myogenic Responses

scholarly journals Reduced Uterine Perfusion Pressure in Pregnant Rats Impairs Cerebral Vascular Myogenic Responses

2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
Michael J Ryan ◽  
Emily L Gilbert ◽  
Porter H Glover ◽  
Babbette D LaMarca ◽  
Joey P Granger
Keyword(s):  
Perfusion Pressure ◽  
Pregnant Rats ◽  
Myogenic Responses ◽  
Uterine Perfusion ◽  
Cerebral Vascular

scholarly journals Potassium channelopathy-like defect underlies early-stage cerebrovascular dysfunction in a genetic model of small vessel disease

2015 ◽  
Vol 112 (7) ◽  
pp. E796-E805 ◽  
Author(s):  
Fabrice Dabertrand ◽  
Christel Krøigaard ◽  
Adrian D. Bonev ◽  
Emmanuel Cognat ◽  
Thomas Dalsgaard ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Genetic Model ◽  
Small Vessel Disease ◽  
Early Stage ◽  
Mesenteric Arteries ◽  
Small Vessel ◽  
Pial Arteries ◽  
Vessel Disease ◽  
Myogenic Responses ◽  
The Brain

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), caused by dominant mutations in the NOTCH3 receptor in vascular smooth muscle, is a genetic paradigm of small vessel disease (SVD) of the brain. Recent studies using transgenic (Tg)Notch3R169C mice, a genetic model of CADASIL, revealed functional defects in cerebral (pial) arteries on the surface of the brain at an early stage of disease progression. Here, using parenchymal arterioles (PAs) from within the brain, we determined the molecular mechanism underlying the early functional deficits associated with this Notch3 mutation. At physiological pressure (40 mmHg), smooth muscle membrane potential depolarization and constriction to pressure (myogenic tone) were blunted in PAs from TgNotch3R169C mice. This effect was associated with an ∼60% increase in the number of voltage-gated potassium (KV) channels, which oppose pressure-induced depolarization. Inhibition of KV1 channels with 4-aminopyridine (4-AP) or treatment with the epidermal growth factor receptor agonist heparin-binding EGF (HB-EGF), which promotes KV1 channel endocytosis, reduced KV current density and restored myogenic responses in PAs from TgNotch3R169C mice, whereas pharmacological inhibition of other major vasodilatory influences had no effect. KV1 currents and myogenic responses were similarly altered in pial arteries from TgNotch3R169C mice, but not in mesenteric arteries. Interestingly, HB-EGF had no effect on mesenteric arteries, suggesting a possible mechanistic basis for the exclusive cerebrovascular manifestation of CADASIL. Collectively, our results indicate that increasing the number of KV1 channels in cerebral smooth muscle produces a mutant vascular phenotype akin to a channelopathy in a genetic model of SVD.

Myogenic Responses of Isolated Lymphatics: Modulation by Endothelium

1997 ◽  
Vol 4 (4) ◽  
pp. 413-420 ◽  
Author(s):  
Risuke Mizuno ◽  
Gabriella Dörnyei ◽  
Akos Koller ◽  
Gabor Kaley
Keyword(s):  
Myogenic Responses

scholarly journals State-of-the-art assessment allows for improved vestibular evoked myogenic potential test-retest reliability

2018 ◽  
Vol 8 (2) ◽  
Author(s):  
Lydia Behtani ◽  
Maxime Maheu ◽  
Audrey Delcenserie ◽  
Mujda Nooristani ◽  
François Champoux
Keyword(s):  
State Of The Art ◽  
Vestibular Evoked Myogenic Potentials ◽  
Vestibular Evoked Myogenic Potential ◽  
Retest Reliability ◽  
Vestibular Assessment ◽  
Myogenic Responses ◽  
Neurologically Normal ◽  
Test Retest Reliability ◽  
The Impact ◽  
Potential Test

The goal of the present study was to evaluate the test-retest reliability values of myogenic responses using the latest guidelines for vestibular assessment. Twenty-two otologically and neurologically normal adults were assessed twice, on two different days. The analyses were carried out using interclass correlations. The results showed that the latest recommendations for vestibular assessment lead to test-retest reliability values that are as high, or greater, than those reported in previous studies. The results suggest that state-of-the-art testing, using the latest recommendations as well as electromyography control, improves reliability values of myogenic responses, more specifically for the cervical vestibular evoked myogenic potentials. The impact of small differences in experimental procedures on the reliability values of myogenic responses is also addressed.

Abstract P266: Thromboxane-prostanoid Receptors (tp-rs) Mediate Hypertension, H2o2 Generation and Impaired Renal Afferent Arteriolar Myogenic Responses Leading to Nephropathy in Doca/salt Mice

Hypertension ◽  
2016 ◽  
Vol 68 (suppl_1) ◽  
Author(s):  
Christopher S Wilcox ◽  
Lingli Li ◽  
En Yin Lai ◽  
Adam Hosszu ◽  
William J Welch
Keyword(s):  
Blood Pressure ◽  
Perfusion Pressure ◽  
High Salt ◽  
Myogenic Tone ◽  
Prostanoid Receptors ◽  
Hypertensive Nephropathy ◽  
Sham Treatment ◽  
H2o2 Generation ◽  
Afferent Arterioles ◽  
Myogenic Responses

Background: DOCA/uninephrectomy/high salt (DOCA) is a model of hypertensive nephropathy. Afferent arteriolar myogenic responses prevent hypertensive renal barotrauma but myogenic tone is blocked by vascular generation of H 2 O 2 . Since thromboxane-prostanoid receptors (TP-Rs) generate H 2 O 2 , we tested the hypothesis that they mediate hypertensive nephropathy. Methods: DOCA and Sham TP-R +/+ and -/- mice (n=6/group) were studied at 2 weeks and myogenic responses recorded from the diameter of perfused single afferent arterioles studied in a bath preparation during increased perfusion pressure (40 to 80 mmHg). Results: DOCA treatment in TP-R +/+ mice increased (p<0.001) 24-hour excretion of H 2 O 2 (45 ± 3 vs 220 + 15 nmol) , TxB 2 (4 ± 2 vs 29 ± 4 pmol) and albumin (20 ± 5 vs 270 ± 20 mg) and increased MAP by 35 ± 5 mmHg. However, all effects of DOCA were prevented in TP-R -/- mice. Sham treatment had no effect in TPR +/+ or -/- mice. Myogenic responses were severely impaired in DOCA vs sham WT mice (Δ diameter: -4 ± 1 vs -8 ± 1%; p< 0.005). Myogenic responses also were reduced by incubation of arterioles with 10 -10 mol·l -1 of the TP-R mimetic, U-46,619 vs vehicle added to the bath for 10 minutes (Δ diameter: -7 ± 1 vs -10 ± 1%; p<0.01) and in WT mice infused for 3 days with U-46,619 (500 ng·kg -1 ·d -1 x 3) vs vehicle (Δ diameter: -3 ± 1 vs -10 ± 1%; p<0.005). Conclusion: Hypertensive nephropathy is dependent on TP-Rs that mediate the increase in H 2 O 2 and blood pressure and likely the impaired myogenic responses that expose the kidney to barotrauma

Pressure-Induced Myogenic Responses in Human Isolated Cerebral Resistance Arteries

Stroke ◽  
1996 ◽  
Vol 27 (12) ◽  
pp. 2287-2291 ◽  
Author(s):  
Sarah J. Wallis ◽  
John Firth ◽  
William R. Dunn
Keyword(s):  
Resistance Arteries ◽  
Myogenic Responses ◽  
Cerebral Resistance

Remote effects of pressure changes in arterioles

1995 ◽  
Vol 268 (3) ◽  
pp. H1379-H1382 ◽  
Author(s):  
R. J. Rivers
Keyword(s):  
Cheek Pouch ◽  
Pressure Flow ◽  
Isolated Segment ◽  
Myogenic Responses ◽  
Pressure Changes ◽  
Remote Response

Blood is distributed to match the demands of the tissue in accordance with the local effectors of pressure, flow, nerves, and metabolites. Influences of these effectors are integrated and communicated to larger vessels to create a coordinated upstream response that allows for the blood required to meet the metabolic demands of the tissue. Each effector's contribution to the communicated response is unknown. In the present study in situ segments of arteriole, within the cheek pouch of the anesthetized hamster, were isolated from the pressure and flow of the surrounding vasculature while maintaining electrotonic continuity. Pressure was transiently increased or decreased (-70 to +120 cmH2O) for 60 s. These pressure changes within the isolated segment caused myogenic responses within the isolated segment as well as changes in diameter at remote arteriolar locations (ranging from -8 to 5 microns) that were outside the isolated segment and insulated from the changes in pressure. The size of the remote response correlated significantly with the change in pressure inside the isolated segment. This demonstrates that the effects of pressure changes in arterioles are communicated to neighboring portions of the vasculature.

Specific Mechanotransduction Signaling Involved in Myogenic Responses of the Cerebral Arteries

2009 ◽  
pp. 453-481 ◽  
Author(s):  
Koichi Nakayama ◽  
Kazuo Obara ◽  
Tomohisa Ishikawa ◽  
Shigeru Nishizawa
Keyword(s):  
Cerebral Arteries ◽  
Myogenic Responses
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