G. Marano et al., Endothelin and mechanical properties of the carotid artery in Wistar-Kyotoand spontaneously hypertensive rats, CARDIO RES, 41(3), 1999, pp. 701-707
Citations number
27
Categorie Soggetti
Cardiovascular & Respiratory Systems","Cardiovascular & Hematology Research
The aim of this study is to evaluate the role of endothelin in the control
of the static mechanical properties of in vitro carotid arteries from 14-we
ek-old Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR). An in
vitro preparation in which the artery was allowed to longitudinally elongat
e similarly to the in situ carotid artery was employed. The diameter of in
vitro carotid arteries subjected to static pressures (from 25 to 200 mmHg i
n 25 mmHg steps) was determined by videomicroscopy and computer-assisted im
age analysis, the cross-sectional compliance- and distensibility-pressure c
urves being then derived. The role of endothelin was assessed by incubating
carotid arteries with the selective ETA and ETB endothelin receptor antago
nists BQ123 and BQ788, respectively. These effects were compared with those
observed under control conditions, as well as with those following complet
e abolition of vascular smooth muscle tone by potassium cyanide (KCN). Caro
tid diameter was significantly larger, and compliance and distensibility si
gnificantly smaller, in SHR compared to WKY rats. Local incubation with BQ1
23 was associated with significant dilations as well as significant increas
es in cross-sectional compliance and distensibility in both strains. This w
as even more pronounced with KCN, while BQ788 had no effect. The results of
the present study suggest that: (i) endothelin exerts a tonic stiffening e
ffect on the in vitro common carotid artery; (ii) this effect is mediated v
ia the ETA endothelin receptor, and (iii) the stiffening effect of endothel
in is exerted to a similar extent in the carotid arteries of normotensive W
KY and SHR rats. (C) 1999 Elsevier Science B.V. All rights reserved.