Effects of hypertension on hypercholesterolemia-induced changes in contraction of rabbit aorta and carotid artery.
Reactivity of aortic and carotid strip from control; hypertensive; hypercholesterolemic; and hypertensive/hypercholesterolemic rabbits were studied. Maximal stress was less in strips from hypertensive/hypercholesterolemic animals. Norepinephrine sensitivity was increased in the carotid artery from hypertensive/hypercholesterolemic animals (EC50: 0.11 microM; 0.35 microM control). CaCl2 sensitivity during norepinephrine-induced contractions was enhanced by hypertension and hypercholesterolemia (carotid EC50: 0.10 mM; 0.38 mM control; aorta EC50: 0.12 mM; 0.82 mM control). Similar results were obtained during membrane depolarization. 5-hydroxytryptamine sensitivity (EC50: 0.15 microM carotid; 0.18 microM aorta) was decreased during hypertension (EC50: 0.51 microM carotid; 1.13 microM aorta) and by hypercholesterolemia (EC50: 1.76 microM carotid; 1.53 microM aorta). Our results support the hypothesis that hypertension and hypercholesterolemia increase vascular sensitivity by increasing Ca2+ permeability. Our results also suggest that hypertension and hypercholesterolemia selectively decrease 5-hydroxytryptamine-induced contractions.
Moreland
R S
RS
Cardiovascular Institute, Boston University School of Medicine, MA 02118, USA.
Lichtenstein
A H
AH
Chobanian
A V
AV
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000502:physiology*; D002122:Calcium Chloride / Q000494:pharmacology; D002339:Carotid Arteries / Q000187:drug effects / Q000502:physiology*; D002784:Cholesterol / Q000008:administration & dosage / Q000633:toxicity; D006937:Hypercholesterolemia / Q000139:chemically induced / Q000503:physiopathology*; D006977:Hypertension, Renal / Q000209:etiology / Q000503:physiopathology*; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009638:Norepinephrine / Q000494:pharmacology; D011817:Rabbits; D012701:Serotonin / Q000494:pharmacology; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D014662:Vasoconstrictor Agents; D012701:Serotonin; D002784:Cholesterol; D002122:Calcium Chloride; D009638:Norepinephrine