Wire myograph is a device for the in vitro investigation of both, active and passive properties of arteries. Arteries from a variety of animal species, pathological states, and vascular beds were investigated using this method. We focus on the normalization procedure which is aimed to standardize experimental settings and, in part, to simulate physiological conditions. During normalization, it is determined the internal circumference of a vessel stretched to a tension that corresponds to the transmural pressure of 100 mm Hg (IC100). Once it is determined, the internal circumference is traditionally set to (0.9 ⋅ IC100). However, this constant 0.9, called also the normalization factor (NF), was experimentally determined for rat small mesenteric arteries only. Therefore, the aim of our work was to show the influence of different NFs on the passive tension and reactivity of both, rat femoral arteries (FA) an d the first branches of superior mesenteric arteries (MA). We found out that the maximal active wall tension of the FA was achieved at the NF value of 1.1, and that of the MA at 0.9. Considering the values of the active wall tension we suggest that higher reactivity and better signal-to- noise ratio in FA can be achieved when the NF is set at least to 1.0., P. Slezák, I. Waczulíková, P. Bališ, A. Púzserová., and Obsahuje bibliografii
In functional arterial studies using wire myography, the determination of a vessel’s standardized normalization factor (factor k) is an essential step to ensure optimal contraction and relaxation by the arteries when stimulated with their respective vasoactive agents and to obtain reproducible results. The optimal factor k for several arteries have been determined, however, the optimal initial tension and factor k for the arteries involved in erection remains unknown. Hence, in the present study we set out to determine the optimal factor k for the internal iliac artery, proximal and distal internal pudendal artery (IPA), and dorsal penile artery. After isolating, harvesting, and mounting the arteries from male Sprague-Dawley rats on a multi wire myograph, we tested arterial responsivity to high K+-stimulation when the factor k was set at 0.7, 0.8, 0.85, 0.9, 0.95, 1.0, 1.1, and 1.2 to determine the factor k setting that results in the greatest K+-induced active force production for each vessel type. The data showed the optimal factor k is 0.90-0.95 for the dorsal penile, distal internal pudendal and internal iliac arteries while it is 0.85-0.90 for proximal internal pudendal artery. These optimal values corresponded to initial passive tension settings of 1.10±0.16 - 1.46±0.23, 1.28±0.20 - 1.69±0.34, 1.03±0.27 - 1.33±0.31, and 1.33±0.31 - 1.77±0.43 mN/mm for the dorsal penile, distal IP, proximal IP, and internal iliac arteries, respectively.
The aim of the present study was to determine the optimal initial tension, i.e. initial stretch for rat coronary artery when using the multi-wire myograph system. We used the normalization procedure to mimic physiological conditions and to stretch the coronary arterial segments to normalized internal circumference (IC 1 ). It is determined the internal circumference when the vessel relaxed under a transmural pressure of 100 mm Hg (IC 100 ), and the IC 1 is calculated by multiplying the IC 100 by a factor k. The impact of different factor k on the initial stretch and agonist- induced tension of coronary arteries were investigated. The results showed that the maximal agonist-induced tension was achieved at the factor k value of 0.90 and the initial stretch tension was given 1.16±0.04 mN/mm. The most appropriate factor k value was 0.90-0.95 and the most appropriate initial tension was 1.16-1.52 mN/mm. Th e equilibration time of the coronary artery segments should be at least 1.0 h. In the same optimal initial tension, the agonist-induced tension increased as equilibration time lengthened., N.-N. Ping ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy