title: Differing effects of metoprolol and propranolol on large vessel and microvessel responsiveness in a porcine model of coronary spasm.
abstract: OBJECTIVE
  The purpose of this study is to assess the effect of beta1-selective blocker on coronary vasospasm.
  
  
  METHODS
  Balloon epicardial coronary artery endothelial denudation was performed at the left anterior descending coronary artery every 2 weeks for a total of 4 times in pigs. Changes in denuded site diameter and left anterior descending coronary artery blood flow caused by acetylcholine or serotonin were assessed before each endothelial denudation and at week 8 in untreated pigs (ED group) and in those treated with metoprolol (Meto group) or propranolol (Pro group).
  
  
  RESULTS
  In the ED group, decreased blood flow response to acetylcholine enhanced from -20+/-10% before the first ED to -100% (i.e. zero flow) at week 8 without denuded site narrowing, suggesting microvascular spasm, and serotonin-induced left anterior descending coronary artery diameter reduction at week 8 was -92+/-15%. In the Pro group, blood flow reduction by acetylcholine and left anterior descending coronary artery diameter reduction by serotonin did not change compared with those of the ED group. In the Meto group however, blood flow reduction by acetylcholine (week 8, -70+/-16%) and left anterior descending coronary artery diameter reduction by serotonin (week 8, -64+/-15%) were blunted (P<0.01) compared with those of ED and Pro groups.
  
  
  CONCLUSIONS
  The beta1-selective blocker metoprolol was effective to prevent coronary vasospasm.
authors.affiliation: Department of Internal Medicine, Fukushima Medical University, Fukushima, Japan.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Muto
authors.forename: Shu-Ichi
authors.initials: S
authors.lastname: Saitoh
authors.forename: Taku
authors.initials: T
authors.lastname: Osugi
authors.forename: Ken
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Aikawa
authors.forename: Futoshi
authors.initials: F
authors.lastname: Onogi
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Ishibashi
authors.forename: Yukio
authors.initials: Y
authors.lastname: Maruyama
mesh_terms: D000109:Acetylcholine / Q000378:metabolism / Q000494:pharmacology; D058671:Adrenergic beta-1 Receptor Antagonists; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000818:Animals; D018678:Cholinergic Agents / Q000494:pharmacology; D017023:Coronary Angiography; D003329:Coronary Vasospasm / Q000378:metabolism / Q000517:prevention & control*; D003331:Coronary Vessels / Q000187:drug effects* / Q000378:metabolism; D003683:Dehydroascorbic Acid / Q000031:analogs & derivatives / Q000097:blood; D004195:Disease Models, Animal; D017078:Laser-Doppler Flowmetry; D008790:Metoprolol / Q000494:pharmacology*; D009569:Nitric Oxide / Q000097:blood; D011433:Propranolol / Q000494:pharmacology*; D012701:Serotonin / Q000378:metabolism / Q000494:pharmacology; D018490:Serotonin Agents / Q000494:pharmacology; D013552:Swine
chemical_list: D058671:Adrenergic beta-1 Receptor Antagonists; D000319:Adrenergic beta-Antagonists; D018678:Cholinergic Agents; D018490:Serotonin Agents; D009569:Nitric Oxide; D012701:Serotonin; C000820:semidehydroascorbic acid; D011433:Propranolol; D008790:Metoprolol; D000109:Acetylcholine; D003683:Dehydroascorbic Acid