Prolonged adenosine triphosphate infusion and exercise hyperemia in humans

John R A Shepherd, Michael Joseph Joyner, Frank A. Dinenno, Timothy B Curry, Sushant M. Ranadive

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

In humans, intra-arterial ATP infusion in limbs mimics many features of exercise hyperemia. However, it remains unknown whether ATP can evoke the prolonged vasodilation seen during exercise. Therefore, we addressed two questions during a continuous 3-h brachial artery infusion of ATP [20 g100 ml forearm volume (FAV)1min1]: 1) would skeletal muscle blood flow remain robust or wane over time (tachyphylaxis); and 2) would the hyperemic response to moderate-intensity exercise performed during the ATP administration be blunted compared with that during control (saline) infusion. Nine participants (25 1 yr) performed one trial consisting of seven bouts of rhythmic handgrip exercise (20 contractions/min at 20% of maximum), two bouts during saline (control), and five bouts during 180 min of continuous ATP infusion. Five minutes of ATP infusion resulted in a 710% increase in forearm vascular conductance (FVC) from control (4.8 0.77 vs. 35.0 5.7 mlmin1100 mmHg1dl FAV1, P<0.05). Contrary to our expectations, FVC did not wane over time with values of 35.0 5.7 and 36.0 7.7 mlmin1100 mmHg1dl FAV1 (P<0.05), seen prior to the exercise bouts at 5 vs. 150 min, respectively. During superimposed exercise, FVC increased from 35.0 5.7 to 49.6 5.4 mlmin1100 mmHg1dl FAV1 at 5 min and 36.0 7.7 to 54.5 5.0 at 150 min (P<0.05). Our findings demonstrate ATP vasodilation is prolonged over time without tachyphylaxis; however, exercise hyperemia responses remain intact. Our results challenge the metabolic theory of exercise hyperemia, suggesting a disconnect between matching of blood flow and metabolic demand.

Original languageEnglish (US)
Pages (from-to)629-635
Number of pages7
JournalJournal of Applied Physiology
Volume121
Issue number3
DOIs
StatePublished - Sep 1 2016

Fingerprint

Hyperemia
Adenosine Triphosphate
Forearm
Tachyphylaxis
Blood Vessels
Vasodilation
Intra Arterial Infusions
Brachial Artery
Skeletal Muscle
Extremities

Keywords

  • Adenosine triphosphate
  • Blood flow
  • Exercise hyperemia
  • Tachyphylaxis
  • Vasodilation

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Cite this

Prolonged adenosine triphosphate infusion and exercise hyperemia in humans. / Shepherd, John R A; Joyner, Michael Joseph; Dinenno, Frank A.; Curry, Timothy B; Ranadive, Sushant M.

In: Journal of Applied Physiology, Vol. 121, No. 3, 01.09.2016, p. 629-635.

Research output: Contribution to journalArticle

Shepherd, John R A ; Joyner, Michael Joseph ; Dinenno, Frank A. ; Curry, Timothy B ; Ranadive, Sushant M. / Prolonged adenosine triphosphate infusion and exercise hyperemia in humans. In: Journal of Applied Physiology. 2016 ; Vol. 121, No. 3. pp. 629-635.
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