Mesenteric धमनी संकुचन और विश्राम अध्ययन स्वचालित वायर Myography का उपयोग
Summary
पृथक mesenteric धमनियों में बल के मापन के लिए एक स्वचालित myography विधि वर्णित है. यह एक ऑटो Mulvany हेल्पर्न दोहरी वायर phenylephrine और कोशिकी कैल्शियम प्रतिक्रियाओं निर्धारित 510A Myograph कार्यरत हैं. 300 सुक्ष्ममापी, स्वतंत्र विधि isometric प्रतिक्रियाओं का लगातार 60 के diameters के छोटे जहाजों में agonists के लिए दृढ़ संकल्प की अनुमति देता है.
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
उच्च रक्तचाप हृदय, मस्तिष्क और गुर्दे की रुग्णता / मृत्यु का एक प्रमुख कारण है. उच्च रक्तचाप की घटना जनसंख्या में अधिक है और नमक के प्रति संवेदनशील उच्च रक्तचाप उम्र बढ़ने की आबादी में विशेष रूप से उच्च …
Disclosures
The authors have nothing to disclose.
Acknowledgements
वर्णित परियोजना पुरस्कार R01 HL064761 नंबर, HL059868 R25, 1SC1 HL099139 और P20 MD000175 स्वास्थ्य के रूप राष्ट्रीय संस्थानों द्वारा समर्थित किया गया था. सामग्री केवल लेखकों की ज़िम्मेदारी है और स्वास्थ्य के राष्ट्रीय संस्थान के आधिकारिक विचार जरूरी नहीं प्रतिनिधित्व करते हैं.
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. |
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