Contribution of cyclic GMP formation to KRN2391-induced relaxation in coronary artery of the pig. |
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Authors: | Y Jinno H Kasai H Ohta K Nishikori H Fukushima and N Ogawa |
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Institution: | Pharmaceutical Research Laboratory of Kirin Brewery Co., Ltd., Gunma, Japan. |
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Abstract: | 1. In the present study, we investigated the relationship between relaxation and guanosine 3':5'-cyclic monophosphate (cyclic GMP) formation induced by KRN2391, compared with those induced by nicorandil and nitroglycerin, in the coronary artery of the pig. 2. KRN2391 (10(-8)-3 X 10(-5) M), nicorandil (10(-8)-3 X 10(-4) M) and nitroglycerin (10(-9)-10(-5) M) antagonized the contraction caused by 25 mM KCl in a concentration-dependent manner. 3. The concentration-relaxation curves for KRN2391, nicorandil and nitroglycerin shifted rightward in the presence of methylene blue (10(-5) M). 4. KRN2391 (10(-6) M), nicorandil (10(-4) M) and nitroglycerin (10(-6) M) induced an increased in cyclic GMP. 5. The magnitude of the shift of the concentration-relaxation curve caused by methylene blue and the increase in cyclic GMP with KRN2391 were lower than those with nicorandil and nitroglycerin. 6. The adenosine 3':5'-cyclic monophosphate (cyclic AMP) level was not increased by KRN2391 even at a concentration that produced full relaxation. 7. The present results suggest that KRN2391-induced relaxation in the coronary artery of the pig is partly due to the increase in cyclic GMP formation through the stimulation of guanylate cyclase. |
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