β-receptor agonist activity of phenylephrine in the human forearm

Klaus D Torp, Michael E. Tschakovsky, John R. Halliwill, Christopher T. Minson, Michael Joseph Joyner

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

β-Receptor agonist activity of phenylephrine in the human forearm. J Appl Physiol 90: 1855-1859, 2001. - Phenylephrine is generally regarded as a "pure" α1-agonist. However, after treatment of the forearm with the α-adrenergic-blocking drug phentolamine, brachial artery infusion of phenylephrine can cause transient forearm vasodilation. To determine whether this response was β-receptor mediated, phenylephrine, phentolamine, and propranolol were infused into the brachial arteries of six healthy volunteers. Forearm vascular conductance (FVC) was also calculated and expressed as arbitrary units (units). Infusion of phenylephrine by itself (0.5 μg·dl forearm volume-1·min-1) caused a sustained decrease (P < 0.05) in FVC from 3.5 ± 0.7 to 0.9 ± 0.2 units (P < 0.05). Infusion of the α-blocker phentolamine increased (P < 0.05) baseline FVC to 5.7 ± 1.3 units. Subsequent infusion of phenylephrine after α-blockade caused FVC to increase (P < 0.05) for ∼ 1 min from 5.7 ± 1.3 to a peak of 13.1 ± 1.8 units. Propranolol had no effect on baseline flow, and subsequent phenylephrine infusion after α- and β-blockade caused a small, but significant, sustained decrease in FVC from 5.1 ± 1.0 to 3.6 ± 0.8 units. There were no systemic effects from the infusions, and saline infusion at the same rate (1-2 ml/min) had no forearm vasoconstrictor or dilator effects. These data indicate that in humans phenylephrine can exert transient β2-vasodilator activity when its predominant α-constrictor effects are blocked.

Original languageEnglish (US)
Pages (from-to)1855-1859
Number of pages5
JournalJournal of Applied Physiology
Volume90
Issue number5
StatePublished - 2001

Fingerprint

Phenylephrine
Forearm
Blood Vessels
Phentolamine
Brachial Artery
Propranolol
Vasoconstrictor Agents
Vasodilator Agents
Vasodilation
Adrenergic Agents
Healthy Volunteers

Keywords

  • Adrenergic receptors
  • Blood flow
  • Vasoconstriction

ASJC Scopus subject areas

  • Physiology
  • Endocrinology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Torp, K. D., Tschakovsky, M. E., Halliwill, J. R., Minson, C. T., & Joyner, M. J. (2001). β-receptor agonist activity of phenylephrine in the human forearm. Journal of Applied Physiology, 90(5), 1855-1859.

β-receptor agonist activity of phenylephrine in the human forearm. / Torp, Klaus D; Tschakovsky, Michael E.; Halliwill, John R.; Minson, Christopher T.; Joyner, Michael Joseph.

In: Journal of Applied Physiology, Vol. 90, No. 5, 2001, p. 1855-1859.

Research output: Contribution to journalArticle

Torp, KD, Tschakovsky, ME, Halliwill, JR, Minson, CT & Joyner, MJ 2001, 'β-receptor agonist activity of phenylephrine in the human forearm', Journal of Applied Physiology, vol. 90, no. 5, pp. 1855-1859.
Torp KD, Tschakovsky ME, Halliwill JR, Minson CT, Joyner MJ. β-receptor agonist activity of phenylephrine in the human forearm. Journal of Applied Physiology. 2001;90(5):1855-1859.
Torp, Klaus D ; Tschakovsky, Michael E. ; Halliwill, John R. ; Minson, Christopher T. ; Joyner, Michael Joseph. / β-receptor agonist activity of phenylephrine in the human forearm. In: Journal of Applied Physiology. 2001 ; Vol. 90, No. 5. pp. 1855-1859.
@article{24ffc9cc29d446a0b9512b72d5c923c5,
title = "β-receptor agonist activity of phenylephrine in the human forearm",
abstract = "β-Receptor agonist activity of phenylephrine in the human forearm. J Appl Physiol 90: 1855-1859, 2001. - Phenylephrine is generally regarded as a {"}pure{"} α1-agonist. However, after treatment of the forearm with the α-adrenergic-blocking drug phentolamine, brachial artery infusion of phenylephrine can cause transient forearm vasodilation. To determine whether this response was β-receptor mediated, phenylephrine, phentolamine, and propranolol were infused into the brachial arteries of six healthy volunteers. Forearm vascular conductance (FVC) was also calculated and expressed as arbitrary units (units). Infusion of phenylephrine by itself (0.5 μg·dl forearm volume-1·min-1) caused a sustained decrease (P < 0.05) in FVC from 3.5 ± 0.7 to 0.9 ± 0.2 units (P < 0.05). Infusion of the α-blocker phentolamine increased (P < 0.05) baseline FVC to 5.7 ± 1.3 units. Subsequent infusion of phenylephrine after α-blockade caused FVC to increase (P < 0.05) for ∼ 1 min from 5.7 ± 1.3 to a peak of 13.1 ± 1.8 units. Propranolol had no effect on baseline flow, and subsequent phenylephrine infusion after α- and β-blockade caused a small, but significant, sustained decrease in FVC from 5.1 ± 1.0 to 3.6 ± 0.8 units. There were no systemic effects from the infusions, and saline infusion at the same rate (1-2 ml/min) had no forearm vasoconstrictor or dilator effects. These data indicate that in humans phenylephrine can exert transient β2-vasodilator activity when its predominant α-constrictor effects are blocked.",
keywords = "Adrenergic receptors, Blood flow, Vasoconstriction",
author = "Torp, {Klaus D} and Tschakovsky, {Michael E.} and Halliwill, {John R.} and Minson, {Christopher T.} and Joyner, {Michael Joseph}",
year = "2001",
language = "English (US)",
volume = "90",
pages = "1855--1859",
journal = "Journal of Applied Physiology",
issn = "8750-7587",
publisher = "American Physiological Society",
number = "5",

}

TY - JOUR

T1 - β-receptor agonist activity of phenylephrine in the human forearm

AU - Torp, Klaus D

AU - Tschakovsky, Michael E.

AU - Halliwill, John R.

AU - Minson, Christopher T.

AU - Joyner, Michael Joseph

PY - 2001

Y1 - 2001

N2 - β-Receptor agonist activity of phenylephrine in the human forearm. J Appl Physiol 90: 1855-1859, 2001. - Phenylephrine is generally regarded as a "pure" α1-agonist. However, after treatment of the forearm with the α-adrenergic-blocking drug phentolamine, brachial artery infusion of phenylephrine can cause transient forearm vasodilation. To determine whether this response was β-receptor mediated, phenylephrine, phentolamine, and propranolol were infused into the brachial arteries of six healthy volunteers. Forearm vascular conductance (FVC) was also calculated and expressed as arbitrary units (units). Infusion of phenylephrine by itself (0.5 μg·dl forearm volume-1·min-1) caused a sustained decrease (P < 0.05) in FVC from 3.5 ± 0.7 to 0.9 ± 0.2 units (P < 0.05). Infusion of the α-blocker phentolamine increased (P < 0.05) baseline FVC to 5.7 ± 1.3 units. Subsequent infusion of phenylephrine after α-blockade caused FVC to increase (P < 0.05) for ∼ 1 min from 5.7 ± 1.3 to a peak of 13.1 ± 1.8 units. Propranolol had no effect on baseline flow, and subsequent phenylephrine infusion after α- and β-blockade caused a small, but significant, sustained decrease in FVC from 5.1 ± 1.0 to 3.6 ± 0.8 units. There were no systemic effects from the infusions, and saline infusion at the same rate (1-2 ml/min) had no forearm vasoconstrictor or dilator effects. These data indicate that in humans phenylephrine can exert transient β2-vasodilator activity when its predominant α-constrictor effects are blocked.

AB - β-Receptor agonist activity of phenylephrine in the human forearm. J Appl Physiol 90: 1855-1859, 2001. - Phenylephrine is generally regarded as a "pure" α1-agonist. However, after treatment of the forearm with the α-adrenergic-blocking drug phentolamine, brachial artery infusion of phenylephrine can cause transient forearm vasodilation. To determine whether this response was β-receptor mediated, phenylephrine, phentolamine, and propranolol were infused into the brachial arteries of six healthy volunteers. Forearm vascular conductance (FVC) was also calculated and expressed as arbitrary units (units). Infusion of phenylephrine by itself (0.5 μg·dl forearm volume-1·min-1) caused a sustained decrease (P < 0.05) in FVC from 3.5 ± 0.7 to 0.9 ± 0.2 units (P < 0.05). Infusion of the α-blocker phentolamine increased (P < 0.05) baseline FVC to 5.7 ± 1.3 units. Subsequent infusion of phenylephrine after α-blockade caused FVC to increase (P < 0.05) for ∼ 1 min from 5.7 ± 1.3 to a peak of 13.1 ± 1.8 units. Propranolol had no effect on baseline flow, and subsequent phenylephrine infusion after α- and β-blockade caused a small, but significant, sustained decrease in FVC from 5.1 ± 1.0 to 3.6 ± 0.8 units. There were no systemic effects from the infusions, and saline infusion at the same rate (1-2 ml/min) had no forearm vasoconstrictor or dilator effects. These data indicate that in humans phenylephrine can exert transient β2-vasodilator activity when its predominant α-constrictor effects are blocked.

KW - Adrenergic receptors

KW - Blood flow

KW - Vasoconstriction

UR - http://www.scopus.com/inward/record.url?scp=0035061341&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0035061341&partnerID=8YFLogxK

M3 - Article

C2 - 11299277

AN - SCOPUS:0035061341

VL - 90

SP - 1855

EP - 1859

JO - Journal of Applied Physiology

JF - Journal of Applied Physiology

SN - 8750-7587

IS - 5

ER -