Conditions: Aging
Keywords: metabolism exercise sodium nitroprusside
Allocation: RANDOMIZED | Intervention model: FACTORIAL
Enrollment: 62
Healthy volunteers: yes

Brief summary:
The purpose of this study was to examine the role skeletal muscle perfusion plays in mediating muscle protein synthesis in healthy older and younger individuals. The investigators hypothesized that normalization of muscle perfusion in older men and women via exercise or infusion of a vasodilator would enhance nutritive flow and skeletal muscle protein synthesis in the elderly similar to that of their younger counterparts.

Detailed description:
The purpose of this study was to examine muscle protein metabolism in healthy young and elderly subjects during pharmacologic vasodilation of the lower limb vasculature in combination with increased amino acids delivery. We obtained femoral arteriovenous blood samples and v. lateralis muscle biopsies during a primed continuous infusion of L-\[ring-13C6\] Phenylalanine. Muscle protein kinetics were measured in the basal state and during a 180 min infusion of sodium nitroprusside (SNP) and amino acids (Premsol 10%) (SNP+AA). Skeletal muscle microvascular recruitment and flow were measured during the basal state and SNP+AA using contrast-enhanced ultrasound (CEU).

Arms:
arm 1: 45 minutes of treadmill walking at 40% VO2 peak arm 2: 45 minutes of treadmill walking at 40% VO2 peak arm 3: Sodium Nitroprusside given in a constant infusion for 180 minutes at a rate of 0.114 ug/kg/min arm 4: Sodium Nitroprusside given in a constant infusion for 180 minutes at a rate of 0.114 ug/kg/min arm 5: Sodium Nitroprusside given in a constant infusion for 180 minutes at a rate of 0.114 ug/kg/min and 7.5g amino acid drink taken orally

Interventions: intervention 1: Aerobic Exercise intervention 2: Sodium Nitroprusside intervention 3: Amino Acid Drink
Intervention descriptions: intervention 1: 45 minuties of treadmill walking was completed at 40% VO2 peak intervention 2: Sodium Nitroprusside was given in a constant infusion for 180 minutes at a rate of 0.114 ug/kg/min intervention 3: 7.5 gram Amino Acid drink

Protocol document: