Optimal Wire Myography Normalization for the Rat Dorsal Penile, Internal Pudendal and Internal Iliac Arteries

In functional arterial studies using wire myography, thedetermination of a vessel’s standardized normalization factor(factor k) is an essential step to ensure optimal contraction andrelaxation by the arteries when stimulated with their respectivevasoactive agents and to obtain reproducible results. The optimalfactor k for several arteries have been determined, however, theoptimal initial tension and factor k for the arteries involved inerection remains unknown. Hence, in the present study we setout to determine the optimal factor k for the internal iliac artery,proximal and distal internal pudendal artery (IPA), and dorsalpenile artery. After isolating, harvesting, and mounting thearteries from male Sprague-Dawley rats on a multi wiremyograph, we tested arterial responsivity to high K+-stimulationwhen 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 thegreatest K+-induced active force production for each vessel type.The data showed the optimal factor k is 0.90-0.95 for the dorsalpenile, distal internal pudendal and internal iliac arteries while itis 0.85-0.90 for proximal internal pudendal artery. These optimalvalues corresponded to initial passive tension settings of1.10±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 dorsalpenile, distal IP, proximal IP, and internal iliac arteries,respectively.