Dietary cholesterol enhances impaired endothelium-dependent relaxations in aortas of salt-induced hypertensive Dahl rats.
We investigated the effect of hypercholesterolemia on the vascular reactivity of thoracic aortas isolated from hypertensive Dahl salt-sensitive (DS) rats. DS rats were fed on a low-sodium diet (control group), a low-sodium plus high-cholesterol diet (CHOL group), a high-sodium diet (NaCl group) or a high-sodium plus high-cholesterol diet (NaCl + CHOL group) for 8 weeks. Hypercholesterolemia developed in the CHOL and NaCl + CHOL groups, while hypertension developed in the NaCl and NaCl + CHOL groups, with these changes being greatest in the NaCl + CHOL group. Aortic cholesteryl ester accumulation was attenuated in the aortic rings from the NaCl and NaCl + CHOL groups, compared to the control group. The degree of attenuation in the NaCl + CHOL group was significantly greater than that in the NaCl group. Endothelium-dependent relaxations induced by the calcium ionophore A23187 were attenuated only in the NaCl + CHOL group. Endothelium-independent relaxations in response to sodium nitroprusside were slightly but significantly attenuated in the NaCl + CHOL group. The relaxations in the CHOL group were comparable to those in the control group. These findings indicate that cholesterol feeding strikingly enhances the impaired endothelium-dependent relaxations and the slightly impaired endothelium-independent relaxations in the aorta of DS rats with salt-induced hypertension, parallel to the development of hypertension, hypercholesterolemia and cholesterol deposition.
Kitagawa
S
S
Department of Pharmacology, Mokogawa Women's University, Nishinomiya, Japan.
Yamaguchi
Y
Y
Shinozuka
K
K
Kwon
Y M
YM
Kunitomo
M
M
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001013:Aorta, Thoracic / Q000187:drug effects; D000001:Calcimycin / Q000494:pharmacology; D002788:Cholesterol Esters / Q000378:metabolism; D002791:Cholesterol, Dietary / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000502:physiology*; D006937:Hypercholesterolemia / Q000503:physiopathology; D006973:Hypertension / Q000139:chemically induced / Q000503:physiopathology*; D007476:Ionophores / Q000494:pharmacology; D050356:Lipid Metabolism; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology*; D009599:Nitroprusside / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012982:Sodium, Dietary / Q000494:pharmacology
D000959:Antihypertensive Agents; D002788:Cholesterol Esters; D002791:Cholesterol, Dietary; D007476:Ionophores; D012982:Sodium, Dietary; D009599:Nitroprusside; D000001:Calcimycin; D000109:Acetylcholine