Comparing approaches to assess nitric oxide-dependent cutaneous vasodilation

Inclusion Criteria:
*  men and women
*  18-30 years of age

Exclusion Criteria:
*  Current or recent (within 8 wks) use of medication that could conceivably alter microvascular function \[including (but not limited to) stimulants, antihypertensives, HMG-CoA reductase inhibitors\]
*  Changes or alterations in medication status (starting a new, additional, or different medication or changing the dose of a current medication)
*  Unstable or diagnosed chronic clinical disease, including cardiovascular, metabolic, renal, hepatic, autonomic, autoimmune, or dermatological disease (e.g., hypertension, heart disease, diabetes, hyperlipidemia, psoriasis)
*  Body mass index \<18.5 or \>35 kg/m2
*  Pregnancy (including a positive urine pregnancy test) or breast-feeding
*  Known allergies to pharmacological agents or study drugs
*  Non-English-speaking. Participants need to understand English to follow instructions and comply with procedures conducted during the screening and experimental visits.