Blood pressure and age-dependent changes of endothelium-dependent tension oscillations in different strains of spontaneously hypertensive rats.
The influence of blood pressure and age of spontaneously hypertensive rats on endothelium-dependent tension oscillation of aortic preparation were studied. Rats with different blood pressures, normotensive Wistar Kyoto rats (WKY), spontaneously hypertensive rats (SHR), stroke-prone SHR (SHRSP) and malignant type of SHRSP (M-SHRSP), were used. The effects of antihypertensive treatment of SHRSP on the tension oscillation were also studied. High doses of noradrenaline induced tension oscillations in endothelium-intact preparations of all strains of young rats. The rate of the occurrence of the tension oscillation decreased age-dependently. The decrease was faster when the blood pressure of the rats was higher. Application of acetylcholine in the presence of noradrenaline induced a relaxation and tension oscillations, both of which were negatively dependent on age and blood pressure. Antihypertensive treatment of hypertensive rats with hydralazine or captopril prevented a decrease in incidence of the tension oscillation. These influences of age and blood pressure as well as antihypertensive treatments on the tension oscillation resembled those on the endothelium-dependent relaxation and are thought to be brought about by functional changes of the endothelium.
Research Institute of Hypertension, Kinki University, Osaka-Sayama, Japan.
K
K
Shimamura
K
K
Matsuda
F
F
Sekiguchi
S
S
Sunano
D000109:Acetylcholine / Q000494:pharmacology; D000375:Aging / Q000502:physiology*; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001011:Aorta / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D002216:Captopril / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000502:physiology*; D006830:Hydralazine / Q000494:pharmacology*; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D009638:Norepinephrine / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D017208:Rats, Wistar
D000959:Antihypertensive Agents; D006830:Hydralazine; D002216:Captopril; D000109:Acetylcholine; D009638:Norepinephrine