Effects of Chloroquine on Smooth Muscle Contracted with Noradrenaline or High-Potassium Solutions in the Rat Thoracic Aorta
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概要
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The effects of chloroquine on the smooth muscle of isolated rat aortic segments were investigated in preparations contracted with either noradrenaline or high-potassium. At rest, chloroquine (up to 10^<-4> M) produced no mechanical response, while noradrenaline (10^<-6> M) produced a sustained contraction. In the presence of 10^<-4> M chloroquine, however, the amplitude of contractions produced by noradrenaline was attenuated by about 70%, with no alteration of the resting tension. In preparations contracted either with noradrenaline or with high-K solutions, chloroquine prodeced a concentration-depaendent relaxation. The tension decreased below resting level as a result of the co-application of these simulants. The relaxing actions of chloroquine were not altered by methylene blue (an inhibitor of guanylate cyclase), suggesting that the cyclic GMP-related mechanism was not involoved. The ratio of the amplitude fo chloroquine-induced relaxation was similar in contractions prodeced by differet concectrations of potassium ions, suggesting that chloroquine did not cause relaxation as a result of membrane hyperpolarization. These results suggest that the inhibition of aortic smooth muscle contraction caused by chloroquine is different to that prodeced by endothelium-derived vasodilating factors. It is possible that the inhibition of aortic smooth muscle contraction by chloroquine involves modulation of the contractile systems and their regulatory proteins.
- 日本平滑筋学会の論文
著者
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Aziba Peter
ナイジェリア
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AZIBA Peter
Department of Pharmacology & Therapeutics, University of Ibadan
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OKPAKO D.
Olabisi Onabanjo University Ago Iwoye
関連論文
- Effects of Chloroquine on Smooth Muscle Contracted with Noradrenaline or High-Potassium Solutions in the Rat Thoracic Aorta
- Actions of Chloroquine on Isolated Smooth Muscle Contractions : In Vitro