AIM
To study the functional alpha1-adrenergic receptor (alpha1-AR) subtypes in human right gastroepiploic artery (RGA).
METHODS
The effects of alpha2-AR, alpha1-AR, and alpha1-AR subtype selective antagonists on norepinephrine (NE)-induced vasoconstriction in isolated human RGA were observed by contractile function experiment.
RESULTS
Cumulative concentration-response curves for NE were competitively antagonized in RGA by alpha2-AR selective antagonist yohimbine (pA2 6.82+/-0.28, slope 1.12+/-0.40),alpha1-AR selective antagonist prazosin (pA2 9.77+/-0.22, slope 0.90+/-0.22),alpha1A-AR selective antagonists RS17053 (pA2 8.42+/-0.20, slope 0.93+/-0.20) and 5-MU (pA2 8.42+/-0.22, slope 0.88+/-0.18),alpha1D-AR selective antagonist BMY7378 (pA2 6.84+/-0.32, slope 1.05+/-0.17), and alpha1A-,alpha1B-AR selective antagonist WB4101 (pA2 8.88+/-0.20, slope 1.15+/-0.16). The correlation coefficients between these pA2 values of alpha1-AR selective antagonists with pKi values of which obtained from alpha1A-, alpha1B- and alpha1D-AR cloned cells are 0.95, 0.82, and 0.42. After the vessels were pretreated by chlorethylclonidine (CEC), an alpha1B- and alpha1D-AR irreversible alkylating agent, the pD2 values were changed from 5.9+/-0.5 to 5.6+/-0.6 and the maximal contraction was changed from (8.9+/-3.2) g to (8.0+/-3.2) g, respectively. The difference was not significant.
CONCLUSION
In human RGA, the contraction response is mainly mediated by alpha1-AR, of which alpha1A-AR plays an important role, whereas alpha1B- and alpha1D-AR are not involved in the contraction response.
[1]
C. Han,et al.
Alpha(1)-adrenoceptor subtypes mediating inotropic responses in rat heart.
,
1999,
The Journal of pharmacology and experimental therapeutics.
[2]
M. Underwood,et al.
Use of the right gastroepiploic artery as a coronary artery bypass graft in 307 patients.
,
1998,
Cardiovascular surgery.
[3]
A. Voors,et al.
Low recurrence of angina pectoris after coronary artery bypass graft surgery with bilateral internal thoracic and right gastroepiploic arteries.
,
1998,
Circulation.
[4]
Han Chide,et al.
Quantification of mRNAS for three α1-adrenoceptor subtypes in rat aorta by solution hybridization
,
1996
.
[5]
T. Lüscher,et al.
[Mechanism of coronary bypass graft disease].
,
1993,
Schweizerische medizinische Wochenschrift.
[6]
T. Lüscher,et al.
Similar endothelium-dependent relaxation, but enhanced contractility, of the right gastroepiploic artery as compared with the internal mammary artery.
,
1992,
The Journal of thoracic and cardiovascular surgery.