Characteristics of adrenoceptors in the human radial artery: clinical implications

J Thorac Cardiovasc Surg. 1998 May;115(5):1136-41. doi: 10.1016/S0022-5223(98)70414-3.


Objectives: The radial artery has been suggested to be spastic. Endogenous and exogenous catecholamines and the use of beta-blockers may be related to radial artery spasm, but the characteristics of adrenoceptors in this artery are unknown. This study was designed to characterize the alpha- and beta-adrenoceptor in the human radial artery.

Methods: Ring segments of the radial artery (n = 59) taken from patients undergoing coronary artery bypass grafting were studied in organ chambers. Alpha-adrenoceptor agonists (norepinephrine, methoxamine, and UK14304) and antagonists (phentolamine hydrochloride [INN: phentolamine], prazosin, and yohimbine) were used to characterize the alpha-adrenoceptor. Beta-adrenoceptor function was studied in U46619-precontracted rings in response to isoproterenol (INN: isoprenaline).

Results: Norepinephrine induced 6.9 +/- 0.6 gm (80.6% +/- 6.8% of the contraction by 100 mmol/L KCl), and this was almost fully inhibited by phentolamine hydrochloride (10 micromol/L, p < 0.0001). The contraction force induced by methoxamine (2.9 +/- 0.8 gm) was abolished by 0.5 micromol/L prazosin (p = 0.017). The contraction force induced by UK14304 (1.7 +/- 0.4 gm) was abolished by 1 micromol/L yohimbine. In contrast to the porcine coronary artery used as the control (fully relaxed to isoproterenol), radial artery rings did not have significant relaxation (1.1% +/- 0.8%).

Conclusions: The human radial artery is an alpha-adrenoceptor-dominant artery with little beta-adrenoceptor function. The use of beta-blockers will not likely evoke the spasm of the radial artery. Furthermore, the radial artery has a dominant alpha1-adrenoceptor function, but the postjunctional alpha2-adrenoceptor is also functional. Circulating catecholamines will mainly contract the human radial artery by activation of the alpha1-adrenoceptors and to a lesser extent also by alpha2-adrenoceptors.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic Agonists / pharmacology
  • Adrenergic Antagonists / pharmacology
  • Animals
  • Brimonidine Tartrate
  • Coronary Artery Bypass
  • Coronary Vessels / drug effects
  • Coronary Vessels / physiology
  • Coronary Vessels / surgery
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / physiology
  • Humans
  • Muscle Contraction / drug effects
  • Muscle, Smooth, Vascular / drug effects
  • Muscle, Smooth, Vascular / physiology
  • Norepinephrine / pharmacology
  • Quinoxalines / pharmacology
  • Radial Artery / drug effects
  • Radial Artery / physiology*
  • Radial Artery / transplantation
  • Receptors, Adrenergic, alpha / classification
  • Receptors, Adrenergic, alpha / physiology*
  • Receptors, Adrenergic, beta / physiology*
  • Swine
  • Vasoconstriction


  • Adrenergic Agonists
  • Adrenergic Antagonists
  • Quinoxalines
  • Receptors, Adrenergic, alpha
  • Receptors, Adrenergic, beta
  • Brimonidine Tartrate
  • Norepinephrine