Dependence of media cross-sectional area on circumference of aortic rings from normal and hypertensive rats.
The purpose of this study is to determine if cross-sectional area and media thickness depend on circumference in excised vessels. Measurements were obtained from rat aortic rings chemically fixed after excision. Rings were fixed without distention or after mounting on circular rods of different diameters. Media cross-sectional area increased with circumference but thickness decreased. Thickness and area were significantly greater in the SHR than the WKY rat at all circumferences. Results of a theoretical analysis predict that cross-sectional area and thickness will depend on circumference in excised rings. Best-fit curves of the experimental data to the theoretical relationships show that neither thickness nor cross-sectional area of the aorta is consistently better correlated with circumference in SHRs and WKY rats. The following conclusions are made: (i) Media cross-sectional area and thickness depend on circumference in excised-aortic rings, and (ii) for a specific method of preparation, thickness and cross-sectional area are equally accurate when comparing aortic rings from normal and hypertensive rats. If an experimental determination of the relationship between circumference and cross-sectional area (or thickness) cannot be done, we suggest that a reasonable alternative is to compare these measurements at the same circumference.
Price
J M
JM
Department of Physiology, College of Medicine, University of South Florida, Tampa 33612.
Moher
T J
TJ
Wilmoth
F R
FR
D000818:Animals; D001013:Aorta, Thoracic / Q000033:anatomy & histology* / Q000502:physiology; D006973:Hypertension / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D008433:Mathematics; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY