Hypoglycemia and Autonomic Nervous System Function-B

This study involves three interventions, which are performed in random order. Each intervention involves a 3-day inpatient visit. There is a space of 1-3 months between interventions. The three interventions are: 1) placebo with a hyperinsulinemic euglycemic clamp, 2) spironolactone with a hyperinsulinemic hypoglycemic clamp, or 3) placebo with a hyperinsulinemic hypoglycemic clamp. Each 3-day inpatient visit includes the following. On Day 1, autonomic testing is performed. Autonomic testing includes assessment of Baroreflex Sensitivity (BRS). BRS is assessed using the Modified Oxford procedure, which involves sequential administration of nitroprusside and phenylephrine while measuring heart rate and beat to beat blood pressure with a finapress and assessing Muscle Sympathetic Nerve Activity (MSNA). MSNA is measured using microelectrodes placed near the peroneal nerve. On Day 2, hyperinsulinemic clamps are performed with pre-treatment with either placebo or spironolactone. Modified Oxford Procedures are performed prior to and during each clamp on Day 2. On Day 3, the autonomic testing performed on Day 1 is repeated..