Contribution of vasomotion to vascular resistance: a comparison of arteries from virgin and pregnant rats

• Published in: Journal of applied physiology (1985) 1998-12, Vol.85 (6), p.2255-2260
• Main Authors: Gratton, Robert J, Gandley, Robin E, McCarthy, John F, Michaluk, Walter K, Slinker, Bryan K, McLaughlin, Margaret K
• Format: Article
• Language: English
• Subjects: Adrenergic alpha-Agonists - pharmacology; Anatomy & physiology; Animals; Biological and medical sciences; Blood vessels; Blood vessels and receptors; Female; Fundamental and applied biological sciences. Psychology; In Vitro Techniques; Mathematical models; Mathematics; Mesenteric Arteries - drug effects; Mesenteric Arteries - physiology; Models, Cardiovascular; Oscillometry; Phenylephrine - pharmacology; Pregnancy; Pregnancy, Animal - physiology; Rats; Rats, Sprague-Dawley; Rodents; Vascular Resistance - drug effects; Vascular Resistance - physiology; Vasoconstriction - drug effects; Vasoconstriction - physiology; Vertebrates: cardiovascular system
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.1998.85.6.2255

Departments of 1  Obstetrics, Gynecology and Reproductive Sciences and of 4  Cell Biology and Physiology, University of Pittsburgh, Pittsburgh 15213; 2  Carnegie Mellon Research Institute, Carnegie Mellon University, Pittsburgh, Pennsylvania 15230; and 3  Department of Veterinarian and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, Washington 99164 Intrinsic oscillatory activity, or vasomotion, within the microcirculation has many potential functions, including modulation of vascular resistance. Alterations in oscillatory activity during pregnancy may contribute to the marked reduction in vascular resistance. The purpose of this study was 1 ) to mathematically model the oscillatory changes in vessel diameter and determine the effect on vascular resistance and 2 ) to characterize the vasomotion in resistance arteries of pregnant and nonpregnant (virgin) rats. Mesenteric arteries were isolated from Sprague-Dawley rats and studied in a pressurized arteriograph. Mathematical modeling demonstrated that the resistance in a vessel with vasomotion was greater than that in a static vessel with the same mean radius. During constriction with the 1 -adrenergic agonist phenylephrine, the amplitude of oscillation was less in the arteries from pregnant rats. We conclude that vasomotor activity may provide a mechanism to regulate vascular resistance and blood flow independent of static changes in arterial diameter. During pregnancy the decrease in vasomotor activity in resistance arteries may contribute to the reduction in peripheral vascular resistance. resistance arteries; mesentery; mathematical modeling