2,3-Butanedione monoxime suppresses primarily total calcium handling in canine heart.
Whether 2,3-butanedione monoxime (BDM, < or = 5mmol/l) suppresses primarily crossbridge cycling or total Ca(2+) handling in the blood-perfused whole heart remains controversial. Although BDM seems to suppress primarily total Ca(2+) handling in canine hearts, more evidence is lacking. We therefore analyzed the cardiac mechanoenergetics, namely, E(max) (contractility), PVA (total mechanical energy), and O(2) consumption of canine BDM-treated hearts by our recently developed integrative method to assess myocardial total Ca(2+) handling. This method additionally required the internal Ca(2+) recirculation fraction. We obtained this from the beat constant of the exponential decay component of the postextrasystolic potentiation. Our analysis indicated significant decreases in both internal Ca(2+) recirculation fraction and total Ca(2+) handling in the BDM-treated heart, but virtually no change in the reactivity of E(max) to total Ca(2+) handling. This result corroborates the view that BDM suppresses primarily total Ca(2+) handling rather than crossbridge cycling in the canine blood-perfused heart.
Maesako
M
M
Department of Physiology II, Okayama University Medical School, Okayama, 700-8558 Japan.
Araki
J
J
Lee
S
S
Doi
Y
Y
Imaoka
T
T
Iribe
G
G
Mohri
S
S
Hirakawa
M
M
Harada
M
M
Suga
H
H
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D003931:Diacetyl / Q000031:analogs & derivatives* / Q000494:pharmacology*; D004285:Dogs; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D066298:In Vitro Techniques; D009200:Myocardial Contraction / Q000187:drug effects* / Q000502:physiology; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D016277:Ventricular Function, Left
D004791:Enzyme Inhibitors; C004717:diacetylmonoxime; D003931:Diacetyl; D002118:Calcium