Contractile Properties of Small Arterial Resistance Vessels in Spontaneously Hypertensive and Normotensive Rats
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The direct measurement of the intrinsic mechanical and contractile properites of two categories of small arterial resistance vessels in the mesenteric bed of 5-month-old normotensive Wistar-Kyoto rats and spontaneously hypertensive rats suggests the disturbance to the cardiovascular regulatory system which results in hypertension produces similar cellular responses in both the myocardium and the peripheral vasculature.Abstract:
The small arteries play an important functional role in establishing the increased peripheral resistance found in essential hypertension. This paper concerns the direct measurement of the intrinsic mechanical and contractile properites of two categories of small arterial resistance vessels in the mesenteric bed of 5-month-old normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). The vessels had mean internal diameters of 246 fim and 153 /*m when relaxed at 100 mm Hg effective transmural pressure. Segments (1 mm) were mounted in such a way that internal circumference could be controlled and the circumferential wall tension (T) measured. After mounting, each vessel was maximally activated (by K* depolarization at 37°C in the presence of 5 mM Ca) at an internal circumference for which AT was approximately maximal, where AT = Tactlve Trelaxed. From the average values of AT measured we have estimated (on the basis of Laplace's equation) that the SHR vessel would average values of AT measured we have estimated (on the basis of Laplace's equation) that the SHR vessels would have been able to contract against 34% greater pressures than the WKY vessels (P < 0.001). Optical measurements of the dimensions of these vessels showed a 23% greater wall thickness in the SHR vessels (P < 0.02). There were no significant differences in the calculated active wall stresses of the SHR and WKY vessels; this suggests that the greater contractility found in the SHR vessels may be due to their having a greater smooth muscle cell content. These vessel measurements have been examined as well as the rats' blood pressures and heart to body weight ratios. The comparison points to the possibility that the disturbance to the cardiovascular regulatory system which results in hypertension produces similar cellular responses in both the myocardium and the peripheral vasculature.read more
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References
More filters
Journal ArticleDOI
The ultrastructure of mammalian arterioles and precapillary sphincters.
TL;DR: A system of myoendothelial junctions was discovered which establishes close membranous contacts between endothelium and the media of the terminal arterioles and the precapillary sphincters, and it is proposed that it may be part of a receptor mechanism for humoral transmitter substances.
Journal ArticleDOI
Brief Reviews: A Systems Analysis Approach to Understanding Long-Range Arterial Blood Pressure Control and Hypertension
Arthur C. Guyton,Thomas G. Coleman,Allen W. Cowley,R. Davis Manning,R. A. Norman,John D. Ferguson +5 more
Journal ArticleDOI
Mechanical properties of vascular smooth muscle cells in situ.
TL;DR: A technique to obtain mechanical data from a smooth muscle preparation which only contains about 1,000 smooth muscle cells, and which is thin enough for the cells to be visualised by Nomarski interference microscopy, provides for the first time the means to study the mechanical properties of Smooth muscle cells in situ.
Journal ArticleDOI
Background of increased flow resistance and vascular "reactivity" in spontaneously hypertensive rats.
TL;DR: The results suggest the presence of an increased contractile wall mass in the systemic resistance vessels of SHR encroaching upon their lumina even during maximal dilatation, which can largely alone account for the raised resistance and increased vascular “reactivity” in SHR.
Journal ArticleDOI
The Elastic Properties of the Arterial Wall
TL;DR: In the course of some investigations on the form of the pulse-wave, a number of facts came under my notice which seemed to deserve further investigation, and I was thus led to widen the limits of my experiments.