Брыжеечной артерии Сокращение и отдых Исследования с помощью автоматизированной миография провода
Summary
Автоматизированный метод миография для измерения силы в изолированных артерий брыжеечной описано. В нем занято Mulvany-Гальперн Авто Двойной Myograph провода 510A для определения ответов на фенилэфрин и внеклеточного кальция. Метод позволяет последовательно определения изометрической ответы на агонисты в мелких сосудах диаметром 60 – 300 мкм, независимо друг от друга.
Abstract
Proximal resistance vessels, such as the mesenteric arteries, contribute substantially to the peripheral resistance. These small vessels of between 100-400 μm in diameter function primarily in directing blood flow to various organs according to the overall requirements of the body. The rat mesenteric artery has a diameter greater than 100 μm. The myography technique, first described by Mulvay and Halpern1, was based on the method proposed by Bevan and Osher2. The technique provides information about small vessels under isometric conditions, where substantial shortening of the muscle preparation is prevented. Since force production and sensitivity of vessels to different agonists is dependent on the extent of stretch, according to active tension-length relation, it is essential to conduct contraction studies under isometric conditions to prevent compliance of the mounting wires. Stainless steel wires are preferred to tungsten wires because of oxidation of the latter, which affects recorded responses3.The technique allows for the comparison of agonist-induced contractions of mounted vessels to obtain evidence for normal function of vascular smooth muscle cell receptors.
We have shown in several studies that isolated mesenteric arteries that are contracted with phenylyephrine relax upon addition of cumulative concentrations of extracellular calcium (Ca2+e). The findings led us to conclude that perivascular sensory nerves, which express the G protein-coupled Ca2+-sensing receptor (CaR), mediate this vasorelaxation response. Using an automated wire myography method, we show here that mesenteric arteries from Wistar, Dahl salt-sensitive(DS) and Dahl salt-resistant (DR) rats respond differently to Ca2+e. Tissues from Wistar rats showed higher Ca2+-sensitivity compared to those from DR and DS. Reduced CaR expression in mesenteric arteries from DS rats correlates with reduced Ca2+e-induced relaxation of isolated, pre-contracted arteries. The data suggest that the CaR is required for relaxation of mesenteric arteries under increased adrenergic tone, as occurs in hypertension, and indicate an inherent defect in the CaR signaling pathway in Dahl animals, which is much more severe in DS.
The method is useful in determining vascular reactivity ex vivo in mesenteric resistance arteries and similar small blood vessels and comparisons between different agonists and/or antagonists can be easily and consistently assessed side-by-side6,7,8.
Protocol
Discussion
Гипертония является одной из основных причин сердечно-сосудистых, церебральных и почечных заболеваемости / смертности. Возникновения гипертонии высок среди населения и соль-чувствительной гипертонии особенно высока в старение населения, и более распространенным в черных, чем белых. …
Offenlegungen
The authors have nothing to disclose.
Acknowledgements
Проекта, описанного была поддержана премии номера R01 HL064761, R25 HL059868, 1SC1 HL099139 и P20 MD000175 формы Национальных Институтов Здоровья. Содержание несут их авторы и не обязательно отражает официальную точку зрения Национального института здоровья.
Materials
| Name of equipment/ reagent | Company | Catalogue number | Comments(optional) |
|---|---|---|---|
| Auto Dual Wire Myograph System-510A DMT-USA, Inc. | Atlanta, GA. | 100151 | |
| PowerLab/4SP Data Acquisition System | ADInstruments, Colorado Springs, CO. | ML750 | New models with 4-16 input channels are available. |
| Dell Dimension XPS Gen 4 Computer | Dell | ||
| Stemi SV II (Apo) Dissection Microscope with Ocular | Carl Zeiss International. | ||
| Wistar, Dahl salt-sensitive, Dahl salt-resistant rats | Harlan Sprague Dawley, Indianapolis, IN. | ||
| Rodent chow | Harland Tekland, Madison, WI. | ||
| Phenylephrine | Sigma-Aldrich, St. Louis, MO. | ||
| Other chemicals | All chemicals used were of the purest grades available commercially. |
Referenzen
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