Regulation of beta-adrenoceptors by thyroid hormone and amiodarone in rat myocardiac cells in culture.

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Disatnik MH, Shainberg A

Regulation of beta-adrenoceptors by thyroid hormone and amiodarone in rat myocardiac cells in culture.

Biochem Pharmacol. 1991 Mar 15-Apr 1;41(6-7):1039-44. doi: 10.1016/0006-2952(91)90212-n.

PubMed ID

1672592 [ View in PubMed

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Abstract

Hyperthyroidism is associated with elevation of heart cells sensitivity to catecholamines. We demonstrated that T3(10(-8) M) increased (30%) the number of beta-adrenoceptors in intact heart cells grown in vitro within 48 hr, without changing the affinity of the ligand [3H]CGP-12177. The increase in beta-adrenoceptors in T3-treated myocytes was not associated with an increase in receptor-mediated cAMP production. Amiodarone, an antiarrhythmic drug, reduces the sensitivity of the heart to catecholamines. To investigate this effect, we analysed the influence of amiodarone on the level of beta-adrenergic receptors. Ninety minute preincubation with amiodarone (5 x 10(-5) M) decreased the number of beta-adrenoceptors (35-50%) in intact heart cells and in heart membranes, without affecting the dissociation constants (Kd). Amiodarone inhibited isoproterenol induced cAMP production. These results indicate that the mechanism of action of amiodarone on the heart seems to be a non-competitive inhibition of catecholamine receptors.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Amiodarone	Beta adrenergic receptor (Protein Group)	Protein group	Humans	Yes	Inhibitor Downregulator	Details