caa a22 4500 469079290 CHVBK 20180323132945.0 cr unu---uuuuu 170328e19920301xx s 000 0 eng 10.1007/BF00168697 doi (NATIONALLICENCE)springer-10.1007/BF00168697 Vasorelaxing effect in rat thoracic aorta caused by fraxinellone and dictamine isolated from the Chinese herb Dictamnus dasycarpus Turcz: comparison with cromakalim and Ca2+ channel blockers [Elektronische Daten] [Sheu-Meei Yu, Feng-Nien Ko, Ming-Jai Su, Tian-Shung Wu, Meei-Ling Wang, Tur-Fu Huang, Che-Ming Teng] Summary: The components of Dictamnus dasycarpus Turcz were tested for their vasorelaxing effect on the rat aorta, and fraxinellone and dictamine were shown to be effective vasorelaxants. In high K+ (60 mmol/l) medium, Ca2+ (0.03 to 3 mmol/l)-induced vasoconstriction was inhibited concentration-dependently by both agents. The IC50 for fraxinellone and dictamine were calculated to be about 25 μmol/l and 15 μmol/l (for Ca2+) concentration of (1 mmol/l), respectively. Cromakalim (0.2-10) μmol/l relaxed aortic rings precontracted with 15 but not 60 mmol/l of K+. Fraxinellone and verapamil were more potent and effective in producing relaxation in 60 mmol/l than in 15 mmol/l K+-induced contraction. However, dictamine was more potent in producing relaxation in 5 mmol/l K+-induced contraction. Nifedipine (1 μmol/l), dictamine (100 μmol/l) and fraxinellone (100 μmol/l) relaxed the aortic contraction caused by KCl or Bay K 8644. The tonic contraction elicited by nor adrenaline (NA, 3 μmol/l) was also relaxed by dictamine (500 μmol/l), but not by fraxinellone (500 μmol/l) in the nifedipine (1 μmol/l)-treated aorta. This relaxing effect of dictamine persisted in endothelium-denuded aorta. Glibenclamide (10 μmol/l) shifted the concentration-relaxation curve of cromakalim, but not that of dictamine, to the right in rat aortic rings precontracted with NA. Dictamine (500 μmol/l) did not affect tonic contraction of NA which are reduced by H-7 (1 μmol/l) in Ca2+ depleted medium. In conclusion, fraxinellone is a selective blocker of voltage-dependent Ca2+ channel, while dictamine relaxed the rat aorta by suppressing the Ca2+ influx through both voltage-dependent and receptor-operated Ca2+ channels. Springer-Verlag, 1992 Fraxinellone nationallicence Dictamine nationallicence Cromakalim1 nationallicence Nifedipine nationallicence Ca 2+ channel blockers nationallicence Rat aorta nationallicence Yu Sheu-Meei Pharmacological Institute, College of Medicine, National Taiwan University, Taipei aut Ko Feng-Nien Pharmacological Institute, College of Medicine, National Taiwan University, Taipei aut Su Ming-Jai Pharmacological Institute, College of Medicine, National Taiwan University, Taipei aut Wu Tian-Shung Department of Chemistry, National Cheng-Kung University, Tainan, Taiwan aut Wang Meei-Ling Department of Chemistry, National Cheng-Kung University, Tainan, Taiwan aut Huang Tur-Fu Pharmacological Institute, College of Medicine, National Taiwan University, Taipei aut Teng Che-Ming Pharmacological Institute, College of Medicine, National Taiwan University, Taipei aut Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 345/3(1992-03-01), 349-355 0028-1298 345:3<349 1992 345 210 https://doi.org/10.1007/BF00168697 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00168697 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Yu Sheu-Meei Pharmacological Institute, College of Medicine, National Taiwan University, Taipei aut NATIONALLICENCE 700 1- Ko Feng-Nien Pharmacological Institute, College of Medicine, National Taiwan University, Taipei aut NATIONALLICENCE 700 1- Su Ming-Jai Pharmacological Institute, College of Medicine, National Taiwan University, Taipei aut NATIONALLICENCE 700 1- Wu Tian-Shung Department of Chemistry, National Cheng-Kung University, Tainan, Taiwan aut NATIONALLICENCE 700 1- Wang Meei-Ling Department of Chemistry, National Cheng-Kung University, Tainan, Taiwan aut NATIONALLICENCE 700 1- Huang Tur-Fu Pharmacological Institute, College of Medicine, National Taiwan University, Taipei aut NATIONALLICENCE 700 1- Teng Che-Ming Pharmacological Institute, College of Medicine, National Taiwan University, Taipei aut NATIONALLICENCE 773 0- Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 345/3(1992-03-01), 349-355 0028-1298 345:3<349 1992 345 210 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer