Review Question - QID 210503

A 68-year-old woman presents to the emergency room with chest pain. She reports sudden severe and crushing substernal chest pain that started 1 hour ago. Her past medical history is notable for hypertension, hyperlipidemia, diabetes mellitus, obesity, and a prior myocardial infarction requiring a coronary artery bypass graft 2 years ago. She takes aspirin, metoprolol, lisinopril, spironolactone, atorvastatin, and insulin. She is retired and lives a sedentary lifestyle at home. Her temperature is 98.8°F (37.1°C), blood pressure is 109/68 mmHg, pulse is 118/min, and respirations are 24/min. Before being able to start the physical examination, the patient loses consciousness. Her pulse is palpable but weak. Her blood pressure is now 88/50 mmHg and pulse is 130/min. Her skin is pale, cold, and clammy. An electrocardiogram demonstrates ST elevations in leads I, aVL, V3, V4, V5, and V6. A medication that primarily stimulates which of the following receptors would be most appropriate to improve the hemodynamic status of this patient?