title: Diltiazem, an antagonist of calcium channels, reduces norepinephrine in the rat myocardium.
abstract: The present study examined the effect of diltiazem, a calcium channel antagonist, on potassium (K(+)) depolarization-induced norepinephrine (NE) release in rat myocardium using a flexibly mounted microdialysis technique. When high concentration of KCl (70 mM) was directly infused in rat heart through a microdialysis probe, the level of NE gradually increased in a time dependent manner. However, when a high concentration of KCl (70 mM) was administered to diltiazem-pretreated animals, it failed to increase the KCl-induced dialysate NE. These results suggest that calcium (Ca(2+)) may play a key role in K(+) depolarization-induced NE release in the myocardium.
authors.affiliation: Department of Analytical Chemistry, Ohu University School of Pharmaceutical Sciences, Koriyama, Fukushima 963-8611, Japan. t-obata@pha.ohu-u.ac.jp
authors.forename: Toshio
authors.initials: T
authors.lastname: Obata
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000008:administration & dosage*; D004110:Diltiazem / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D006321:Heart / Q000187:drug effects*; D008297:Male; D017551:Microdialysis; D009206:Myocardium / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism*; D011189:Potassium Chloride / Q000008:administration & dosage*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D002121:Calcium Channel Blockers; D004338:Drug Combinations; D011189:Potassium Chloride; D004110:Diltiazem; D002118:Calcium; D009638:Norepinephrine