Characteristics of adrenoceptors in the human radial artery: Clinical implications
Objectives: The radial artery has been suggested to be spastic. Endogenous and exogenous catecholamines and the use of β-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 α- and β-adrenocep...
Gespeichert in:
Veröffentlicht in: | The Journal of thoracic and cardiovascular surgery 1998-05, Vol.115 (5), p.1136-1141 |
---|---|
Hauptverfasser: | , |
Format: | Artikel |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | Objectives: The radial artery has been suggested to be spastic. Endogenous and exogenous catecholamines and the use of β-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 α- and β-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. α-Adrenoceptor agonists (norepinephrine, methoxamine, and UK14304) and antagonists (phentolamine hydrochloride [INN: phentolamine], prazosin, and yohimbine) were used to characterize the α-adrenoceptor. β-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 μmol/L,
p < 0.0001). The contraction force induced by methoxamine (2.9 ± 0.8 gm) was abolished by 0.5 μmol/L prazosin (
p = 0.017). The contraction force induced by UK14304 (1.7 ± 0.4 gm) was abolished by 1 μmol/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 α-adrenoceptor–dominant artery with little β-adrenoceptor function. The use of β-blockers will not likely evoke the spasm of the radial artery. Furthermore, the radial artery has a dominant α
1-adrenoceptor function, but the postjunctional α
2-adrenoceptor is also functional. Circulating catecholamines will mainly contract the human radial artery by activation of the α
1-adrenoceptors and to a lesser extent also by α
2-adrenoceptors. (J Thorac Cardiovasc Surg 1998;115:88054-41) |
---|---|
ISSN: | 0022-5223 1097-685X |
DOI: | 10.1016/S0022-5223(98)70414-3 |