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Calcium sensitivity of isometric force in intact and chemically skinned aortas during the development of aldosterone-salt hypertension in the rat. 1985

E G McMahon, and R J Paul

We investigated the role of altered vascular calcium handling in the development of aldosterone-salt hypertension in the rat. The calcium sensitivity of isometric force in response to 50 mM KCl was compared in aortic rings from control and aldosterone-hypertensive rats. Over the entire range of calcium concentrations studied, responses in aortas from the hypertensives were significantly depressed compared to controls [ED50: aldosterone-hypertensive rats (n = 6), 0.739 +/- 0.137; controls (n = 7), 0.141 +/- 0.021 mM; P less than 0.001]. However, calcium sensitivity in response to 1 microM norepinephrine was similar in aortas from both hypertensives and controls [ED50: aldosterone-hypertensive rats (n = 7), 0.196 +/- 0.022; controls (n = 7), 0.180 +/- 0.024 mM]. The calcium sensitivity of Triton X-100 skinned aortic rings from aldosterone-hypertensive rats was likewise not significantly different from sensitivity in controls [ED50: aldosterone-hypertensive rats (n = 9), 3.61 X 10(-7) +/- 0.57; controls (n = 8), 3.89 X 10(-7) +/- 0.64 M]. Therefore, the observed decrease in calcium sensitivity in response to membrane depolarization in aortas from aldosterone-hypertensive rats probably is not due to a change in calcium sensitivity of the contractile system itself. The time course for development of changes in calcium handling in vessels from the aldosterone-hypertensive rats was found to be quite different from the time course for changes in monovalent ion metabolism. Whereas increases in monovalent ion permeability reportedly appear as early as one week after the start of aldosterone-salt treatment, significant alterations in calcium handling were not apparent until after four weeks of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

UI MeSH Term Description Entries
D006973 Hypertension Persistently high systemic arterial BLOOD PRESSURE. Based on multiple readings (BLOOD PRESSURE DETERMINATION), hypertension is currently defined as when SYSTOLIC PRESSURE is consistently greater than 140 mm Hg or when DIASTOLIC PRESSURE is consistently 90 mm Hg or more. Blood Pressure, High,Blood Pressures, High,High Blood Pressure,High Blood Pressures
D001794 Blood Pressure PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS. Systolic Pressure,Diastolic Pressure,Pulse Pressure,Pressure, Blood,Pressure, Diastolic,Pressure, Pulse,Pressure, Systolic,Pressures, Systolic
D002118 Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D000450 Aldosterone A hormone secreted by the ADRENAL CORTEX that regulates electrolyte and water balance by increasing the renal retention of sodium and the excretion of potassium. Aldosterone, (+-)-Isomer,Aldosterone, (11 beta,17 alpha)-Isomer
D000818 Animals Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA. Animal,Metazoa,Animalia
D001692 Biological Transport The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments. Transport, Biological,Biologic Transport,Transport, Biologic
D051381 Rats The common name for the genus Rattus. Rattus,Rats, Laboratory,Rats, Norway,Rattus norvegicus,Laboratory Rat,Laboratory Rats,Norway Rat,Norway Rats,Rat,Rat, Laboratory,Rat, Norway,norvegicus, Rattus

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