ABSORPTION SPECTROSCOPY FOR THE ASSESSMENT OF SMALL-ARTERY STRUCTURE

2001 ◽  
Vol 13 (04) ◽  
pp. 175-180
Author(s):  
A. KAUR ◽  
H. FISH ◽  
H. THURSTON ◽  
P. R. SMITH
Keyword(s):  
Blood Vessels ◽  
Transmission Spectra ◽  
Resistance Arteries ◽  
Hypertensive Rats ◽  
Arterial Blood ◽  
Spectroscopic Examination ◽  
Normal Rat ◽  
Small Resistance ◽  
Quasi Newton ◽  
First Time

The assessment of vascular structure gives important information on pathological processes, particularly for the investigation of diseased vessels. In this study the Mulvany wire myogarph is adapted for spectroscopic examination of small arterial blood vessels obtained from hypertensive and normal rat specimens. An experimental study of 20 vessels obtained from adult Wistar rats and Goldblatt (one kidney one clip) hypertensive rats was carried out. Segments of small resistance arteries mounted under isometric conditions on a wire myograph and set to normalised conditions of passive force directly obtained from its circumferential length-tension relationship were morphologically examined and transmission spectra obtained. Features of the observed transmission spectra were extracted by means of an empirical non-linear model using the quasi-Newton method. These features were correlated for the first time with standard descriptors of vessel morplzology, media:lumen ratio and with arterial blood pressure. The extent and significance of such correlations are sufficient to distinguish the presence of hypertension in isolated arterial segments from hypertensive animals. This technique may provide an alternative to light microscopy as well as a potential new tool for the analysis of small blood vessels in the study of vascular disease.

Morphological and functional alterations of mesenteric small resistance arteries in early renal hypertension in rats

1991 ◽  
Vol 261 (4) ◽  
pp. H1171-H1177 ◽  
Author(s):  
L. Y. Deng ◽  
E. L. Schiffrin
Keyword(s):  
Blood Vessels ◽  
Vascular Reactivity ◽  
Rapid Development ◽  
Renal Hypertension ◽  
Lumen Diameter ◽  
External Diameter ◽  
Effective Pressure ◽  
Resistance Arteries ◽  
Hypertensive Rats ◽  
Small Resistance

We investigated the structure and reactivity of small resistance arteries of two-kidney, one-clip (2K,1C) and one-kidney, one-clip (1K,1C) Goldblatt hypertensive rats within 4-6 wk of development of hypertension. Blood vessels from the mesenteric vascular bed with lumen diameter less than 300 microns were mounted on a wire myograph. The media of the vessel wall was significantly increased and lumen diameter was decreased in 2K,1C and 1K,1C rats. External diameter of blood vessels was reduced in both 2K,1C and 1K,1C rats, whereas cross-sectional area of the wall was increased significantly in 1K,1C rats. Wall tension in response to KCl was significantly lower in 2K,1C and 1K,1C hypertensive rats, whereas tension in response to norepinephrine (NE) was reduced in 1K,1C hypertensive rats but was similar in 2K,1C rats and controls. Active tension in response to arginine vasopressin (AVP) was similar in all groups. As a consequence of the reduced lumen circumference of small arteries, effective pressure in response to NE was similar in hypertensive and control rats, whereas effective pressure in response to AVP was exaggerated in the hypertensive rats. The sensitivity to NE and AVP was similar in all groups. These results show the rapid development of functional and structural changes in small resistance arteries in renal hypertensive rats within 4-6 wk of hypertension, with significant reduction in external and lumen diameters, increased media width, and increased media-to-lumen ratio, which enhance vascular reactivity to vasoconstrictors, in particular NE and AVP.

scholarly journals Aqueous Fraction from Hibiscus sabdariffa Relaxes Mesenteric Arteries of Normotensive and Hypertensive Rats through Calcium Current Reduction and Possibly Potassium Channels Modulation

Nutrients ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1782
Author(s):  
Anas M.A. Alsayed ◽  
Bei Li Zhang ◽  
Pierre Bredeloux ◽  
Leslie Boudesocque-Delaye ◽  
Angèle Yu ◽  
...  
Keyword(s):  
Calcium Current ◽  
Mesenteric Arteries ◽  
Hibiscus Sabdariffa ◽  
Resistance Arteries ◽  
Hypertensive Rats ◽  
Aqueous Fraction ◽  
Relaxant Effect ◽  
Vasorelaxant Effect ◽  
Small Resistance ◽  
Current Reduction

Background/Objectives: Hibiscus sabdariffa L. (H. sabdariffa (HS)) extract has a vascular relaxant effect on isolated rat thoracic aorta, but data on small resistance arteries, which play an important role on the development of hypertension, are still missing. The purposes of this study were (1) to assess the effect on isolated mesenteric arteries (MA) from normotensive (Wistar and Wistar-Kyoto (WKY)) and spontaneous hypertensive rats (SHR); (2) to elucidate the mechanism(s) of action underling the relaxant effect in light of bioactive components. Methods: Vascular effects of HS aqueous fraction (AF) on isolated MA rings, as well as its mechanisms of action, were assessed using the contractility and intracellular microelectrode technique. The patch clamp technique was used to evaluate the effect of HS AF on the L-type calcium current. Extraction and enrichment of AF were carried out using liquid–liquid extraction, and the yield was analyzed using HPLC. Results: The HS AF induced a concentration-dependent relaxant effect on MA rings of SHR (EC50 = 0.83 ± 0.08 mg/mL), WKY (EC50 = 0.46 ± 0.04 mg/mL), and Wistar rats (EC50 = 0.44 ± 0.08 mg/mL) pre-contracted with phenylephrine (10 µM). In Wistar rats, the HS AF maximum relaxant effect was not modified after endothelium removal or when a guanylate cyclase inhibitor (ODQ, 10 µM) and a selective β2-adrenergic receptor antagonist (ICI-118551, 1 µM) were incubated with the preparation. Otherwise, it was reduced by 34.57 ± 10.66% when vascular rings were pre-contracted with an 80 mM [K+] solution (p < 0.001), which suggests an effect on ionic channels. HS AF 2 mg/mL significantly decreased the peak of the L-type calcium current observed in cardiac myocytes by 24.4%. Moreover, though the vasorelaxant effect of HS, AF was reduced by 27% when the nonselective potassium channels blocker (tetraethylammonium (TEA) 20 mM) was added to the bath (p < 0.01). The extract did not induce a membrane hyperpolarization of smooth muscle cells, which might suggest an absence of a direct effect on background potassium current. Conclusion: These results highlight that the antihypertensive effect of HS probably involves a vasorelaxant effect on small resistance arteries, which is endothelium independent. L-type calcium current reduction contributes to this effect. The results could also provide a link between the vasorelaxant effect and the bioactive compounds, especially anthocyanins.

Effects of endothelin on resistance arteries of DOCA-salt hypertensive rats

1992 ◽  
Vol 262 (6) ◽  
pp. H1782-H1787 ◽  
Author(s):  
L. Y. Deng ◽  
E. L. Schiffrin
Keyword(s):  
Lumen Diameter ◽  
Acute Effects ◽  
Resistance Arteries ◽  
Hypertensive Rats ◽  
Cross Sectional ◽  
Functional Changes ◽  
Tension Response ◽  
Maximal Tension ◽  
Nonionic Detergent ◽  
Small Resistance

The effect of endothelin (ET)-1 was investigated on resistance arteries of less than 300-microns lumen diameter from the mesenteric circulation, mounted on a wire myograph, in deoxycorticosterone acetate (DOCA)-salt hypertensive rats within 2 wk of developing hypertension and in uninephrectomized controls. Arteries from DOCA-salt hypertensive rats presented a significantly reduced external and lumen diameter and increased media width and wall cross-sectional area. Vessels from DOCA-salt hypertensive rats responded to ET-1 with lower active wall tension and media stress. Because the lumen diameter was significantly decreased in DOCA-salt hypertensive rats, the active pressure developed in response to ET-1 was similar in both groups. In contrast, the maximal tension response to arginine vasopressin was enhanced in DOCA-salt hypertensive rats. The sensitivity to both peptides and norepinephrine (NE) was similar in both groups. After removal of endothelium by exposure to the nonionic detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate, ET-1 elicited tension responses that were also lower in DOCA-salt hypertensive rats, whereas NE responses were similar in both groups. These results demonstrate significant morphological and functional changes in small arteries of DOCA-salt hypertensive rats within 2 wk of developing hypertension and blunted reactivity to ET-1. Because similar results were found after removal of endothelium, it is likely that neither prior receptor occupation by endogenous ET nor acute effects of other endothelial cell products play a role in the reduced responsiveness to ET of vascular smooth muscle of small resistance arteries of DOCA-salt hypertensive rats.

Structural changes of small resistance arteries in spontaneously hypertensive rats after treatment with various doses of lacidipine

1997 ◽  
Vol 15 (6) ◽  
pp. 619-625 ◽  
Author(s):  
Enzo Porteri ◽  
Damiano Rizzoni ◽  
Maurizio Castellano ◽  
Giorgio Bettoni ◽  
Maria Lorenza Muiesan ◽  
...  
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Structural Changes ◽  
Resistance Arteries ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Small Resistance
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