Effects of mebudipine and dibudipine, two new calcium channel blockers, on guinea-pig isolated common bile duct.
The inhibitory effects of calcium channel blockers; nifedipine and two new compounds, mebudipine and dibudipine, on contractions of isolated guinea-pig common bile duct were investigated. All the compounds tested induced a concentration-dependent reduction of the amplitude of contractile response to electrical stimulation and all the compounds displaced concentration-response curve of calcium chloride to the right in a concentration-dependent manner. The pIC50 values for these compounds acting on electrically stimulated common bile duct were calculated as: dibudipine: 8.50 +/- 0.17; mebudipine: 8.27 +/- 0.20; nifedipine: 7.96 +/- 0.07. The compounds also antagonized the contractile response of K+-depolarized guinea-pig common bile duct to cumulative concentration of calcium. However the inhibitory effect of these compounds were not significantly different.
Razi Institute for Drug Researches, Iran University of Medical Sciences, Shaheed Hemmat express way, Tehran, Iran.
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S
Beigly
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Ghiaee
S A
SA
Ebrahimi
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M
Mahmoudian
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D003135:Common Bile Duct / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D004558:Electric Stimulation; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects; D009543:Nifedipine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D010276:Parasympatholytics / Q000494:pharmacology
D002121:Calcium Channel Blockers; D010276:Parasympatholytics; C110813:dibudipine; C110812:mebudipine; D009543:Nifedipine