Increased cardiac alpha-1-adrenoceptor density in rats following treatment with amiodarone.
This study was undertaken to investigate the interaction between amiodarone and alpha-1-adrenoceptors in rat cardiac cells. The level (Bmax) and affinity (Kd) of alpha-1-adrenoceptors in heart cells were determined by [3H]prazosin radioligand binding following amiodarone treatment. In cultured intact cardiocytes treated for 48 h with 10 microM amiodarone, [3H]prazosin binding increased by 31% compared with the control cells (p<0.05). The increase was both dose and time dependent and was found to be specific because no significant change occurred in creatine kinase activity. Additionally, under the same conditions, an increase in [3H]prazosin binding to cultured cardiocyte cell membranes was also obtained. Oral gavage of amiodarone to rats for 8 d resulted in a 25% increase in [3H]prazosin binding to isolated ventricle membranes compared with control rats (p<0.05). We conclude that amiodarone treatment can increase the response to alpha-1-adrenoceptors agonist in the heart due to an increase in the density of alpha-1-adrenoceptors.
Budu
C E
CE
Gonda (Goldschmied) Medical Diagnostic Research Center, Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel.
Balas
N
N
Nawrath
H
H
Wegener
J W
JW
Shainberg
A
A
D000316:Adrenergic alpha-Agonists; D000638:Amiodarone / Q000494:pharmacology*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology*; D002469:Cell Separation; D002478:Cells, Cultured; D003402:Creatine Kinase / Q000378:metabolism; D006321:Heart / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D006352:Heart Ventricles / Q000187:drug effects; D066298:In Vitro Techniques; D007700:Kinetics; D008566:Membranes / Q000187:drug effects / Q000378:metabolism; D009124:Muscle Proteins / Q000096:biosynthesis; D009206:Myocardium / Q000166:cytology; D011869:Radioligand Assay; D051381:Rats; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects*; D018340:Receptors, Adrenergic, alpha-1 / Q000187:drug effects
D000316:Adrenergic alpha-Agonists; D000889:Anti-Arrhythmia Agents; D009124:Muscle Proteins; D011942:Receptors, Adrenergic, alpha; D018340:Receptors, Adrenergic, alpha-1; D003402:Creatine Kinase; D000638:Amiodarone