Abstract
The antiarrhythmic effect of alpha 1-adrenoceptor antagonists during myocardial ischemia and reperfusion remains controversial. The potential antiarrhythmic properties of indoramin, an alpha 1-antagonist, were assessed in the isolated perfused rat heart during regional ischemia and during sustained reperfusion. Coronary artery ligation (CAL) decreased the ventricular fibrillation threshold (VFT) of control hearts from 9.1 +/- 1.3 (pre-CAL, mean +/- SEM) to 2.1 +/- 0.5 mA 15 min post-CAL (p less than 0.0001). Perfusion with indoramin 10(-8) M (alpha 1-receptor antagonistic concentration) started 5 min prior to CAL did not prevent the fall in VFT after CAL. Indoramin 10(-6) M prevented the fall in VFT after CAL relative to the control group. Indoramin 10(-5) M markedly increased the VFT before CAL from 9.9 +/- 1.0 to 28.6 +/- 2.9 mA (p less than 0.0001) and prevented the fall in VFT after CAL. During reperfusion, indoramin 10(-5) M decreased the incidence of spontaneous ventricular fibrillation (VF) to 1 of 6 vs. 6 of 6 in the control group (p less than 0.02). Indoramin 10(-5) M preserved adenosine triphosphate in the reperfused myocardium: 2.82 +/- 0.06 vs. 2.16 +/- 0.21 mumol/g in the control group (p less than 0.05). Specific alpha 1-antagonist properties of indoramin did not appear to be involved in the antiarrhythmic effects.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
