Notes: (±)-Atenolol-d7 is intended for use as an internal standard for the quantification of (±)-atenolol (Item No. 17250) by GC- or LC-MS. (±)-Atenolol is an antagonist of the β1-adrenergic receptor (β1-AR; Ki = 1.14 µM).{28226} It is selective for β1-ARs over β2-ARs (Ki = 48.7 µM). (±)-Atenolol (200 mg/kg per day) delays the onset of hypertension in spontaneously hypertensive rats.{49503} Formulations containing atenolol have been used in the treatment of high blood pressure.