Characterization of beta-adrenoceptors on rat skeletal muscle cells grown in vitro.
The binding properties of an hydrophilic beta-adrenergic receptor radioligand, (-)[3H](4-(3-tert-butylamino-2-hydroxypropoxy)-benzimidazolo-2-one ); ([3H]CGP-12177), were investigated in rat skeletal muscle cells in culture. The binding of [3H]CGP-12177 at 25 degrees was saturable, reversible and of high affinity (Kd = 1.3 +/- 0.3 nM). The maximal number of [3H]CGP-12177 binding sites was 30.6 +/- 3.2 fmol/dish (34 +/- 3.5 fmol/mg protein). beta-Adrenergic agonists and antagonists inhibited [3H]CGP-12177 binding. The competing ligand inhibition binding is a typical one for beta 2-adrenoceptors. The increase in beta-adrenoceptors was independent of cell fusion. Amiodarone (10(-5) M) decreased the beta-adrenoceptor number in skeletal muscle cells differentiated in vitro by 48%, while the affinity for [3H]CGP-12177 was not affected.
Disatnik
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MH
Otto Meryerhoff Drug Receptor Center, Department of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel.
Sampson
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SR
Shainberg
A
A
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000319:Adrenergic beta-Antagonists / Q000378:metabolism*; D000638:Amiodarone / Q000494:pharmacology*; D000818:Animals; D001667:Binding, Competitive; D002478:Cells, Cultured; D008024:Ligands; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism*; D011412:Propanolamines / Q000378:metabolism*; D051381:Rats; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism*
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D008024:Ligands; D011412:Propanolamines; D011943:Receptors, Adrenergic, beta; D000638:Amiodarone; C033394:CGP 12177