Cholesterol depletion disrupts caveolae and differentially impairs agonist-induced arterial contraction.

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Cholesterol depletion disrupts caveolae and differentially impairs agonist-induced arterial contraction. / Dreja, Karl; Voldstedlund, Marianne; Vinten, Jørgen; Tranum-Jensen, Jørgen; Hellstrand, Per; Swärd, Karl.

I: Arteriosclerosis, Thrombosis and Vascular Biology, Vol. 22, Nr. 8, 2002, s. 1267-1272.

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T1 - Cholesterol depletion disrupts caveolae and differentially impairs agonist-induced arterial contraction.

AU - Dreja, Karl

AU - Voldstedlund, Marianne

AU - Vinten, Jørgen

AU - Tranum-Jensen, Jørgen

AU - Hellstrand, Per

AU - Swärd, Karl

N1 - The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Department of Experimental Medical Science (013210000), Unit on Vascular Diabetic Complications (013241510), Vascular Physiology (013212034)

PY - 2002

Y1 - 2002

N2 - OBJECTIVE: This study assessed the role of cholesterol-rich membrane regions, including caveolae, in the regulation of arterial contractility. Methods and Results- Rat tail artery devoid of endothelium was treated with the cholesterol acceptor methyl-beta-cyclodextrin, and the effects on force and Ca2+ handling were evaluated. In cholesterol-depleted preparations, the force responses to alpha1-adrenergic receptors, membrane depolarization, inhibition of myosin light chain phosphatase, and activation of G proteins with a mixture of 20 mmol/L NaF and 60 micro mol/L AlCl3 were unaffected. In contrast, responses to 5-hydroxytryptamine (5-HT), vasopressin, and endothelin were reduced by >50%. The rise in global intracellular free Ca2+ concentration in response to 5-HT was attenuated, as was the generation of Ca2+ waves at the cellular level. By electron microscopy, cholesterol depletion was found to disrupt caveolae. The 5-HT response could be restored by exogenous cholesterol, which also restored caveolae. Western blots showed that the levels of 5-HT2A receptor and of caveolin-1 were unaffected by cholesterol extraction. Sucrose gradient centrifugation showed enrichment of 5-HT2A receptors, but not alpha1-adrenergic receptors, in the caveolin-1-containing fractions, suggesting localization of the former to caveolae. CONCLUSIONS: These results show that a subset of signaling pathways that regulate smooth muscle contraction depends specifically on cholesterol. Furthermore, the cholesterol-dependent step in serotonergic signaling occurs early in the pathway and depends on the integrity of caveolae.

AB - OBJECTIVE: This study assessed the role of cholesterol-rich membrane regions, including caveolae, in the regulation of arterial contractility. Methods and Results- Rat tail artery devoid of endothelium was treated with the cholesterol acceptor methyl-beta-cyclodextrin, and the effects on force and Ca2+ handling were evaluated. In cholesterol-depleted preparations, the force responses to alpha1-adrenergic receptors, membrane depolarization, inhibition of myosin light chain phosphatase, and activation of G proteins with a mixture of 20 mmol/L NaF and 60 micro mol/L AlCl3 were unaffected. In contrast, responses to 5-hydroxytryptamine (5-HT), vasopressin, and endothelin were reduced by >50%. The rise in global intracellular free Ca2+ concentration in response to 5-HT was attenuated, as was the generation of Ca2+ waves at the cellular level. By electron microscopy, cholesterol depletion was found to disrupt caveolae. The 5-HT response could be restored by exogenous cholesterol, which also restored caveolae. Western blots showed that the levels of 5-HT2A receptor and of caveolin-1 were unaffected by cholesterol extraction. Sucrose gradient centrifugation showed enrichment of 5-HT2A receptors, but not alpha1-adrenergic receptors, in the caveolin-1-containing fractions, suggesting localization of the former to caveolae. CONCLUSIONS: These results show that a subset of signaling pathways that regulate smooth muscle contraction depends specifically on cholesterol. Furthermore, the cholesterol-dependent step in serotonergic signaling occurs early in the pathway and depends on the integrity of caveolae.

KW - 5-hydroxytryptamine

KW - intracellular calcium

KW - endothelin

KW - smooth muscle

KW - caveolae

U2 - 10.1161/01.ATV.0000023438.32585.A1

DO - 10.1161/01.ATV.0000023438.32585.A1

M3 - Article

VL - 22

SP - 1267

EP - 1272

JO - Arteriosclerosis, Thrombosis and Vascular Biology

JF - Arteriosclerosis, Thrombosis and Vascular Biology

SN - 1524-4636

IS - 8

ER -