Yonsei Med J.  1969 Dec;10(2):192-195. 10.3349/ymj.1969.10.2.192.

The Effect of Beta-Adrenergic Receptor Blockade on the Atrial Refractory Period of Hyperthyroid Rabbits

• Yoo CS
• Lim KB
• Lee WC

• KMID: 1107461
• DOI: http://doi.org/10.3349/ymj.1969.10.2.192

Abstract

Treatment of rabbits with thyroxine 1 mg/kg daily for three to six days produced a hyperthyroid state as evidenced by increase in the heart rate and PBI. The hyperthyroid animals exhibited a significant shortening of the atrial refractory period. Beta adrenergic receptor blocking agents, propranolol (l0(-6)M pronethalol (5 X 10(-5)M) or MJ-1999 (5 X 10(-4)M), completely blocked the shortening of the atrial refractory period produced by the treatment with thyroxin, and with norepinephrine. Consequently, the shortening of the atrial refractory period of rabbits treated with thyroxin appears to bs mediated through stimulation of the beta adrenergic receptor in the heart. From these results, it may be concluded that the stimulation of the beta adrenergic receptor plays an important role in the alteration of cardiac function found in hyperthyroidism, and that the beta adrenergic blocking agents may be useful in treatment of the cardiac complications of hyperthyroidism.

MeSH Terms

Adrenergic beta-Antagonists/pharmacology
Animals
Female
Heart Atria/*drug effects/physiopathology
Hyperthyroidism/chemically induced/*physiopathology
Male
Rabbits
Sympatholytics/*pharmacology
Thyroxine