ISSN:
1615-2573
Keywords:
Prostacyclin
;
Beraprost sodium
;
Canine femoral vein
;
Thromboxane A2/endoperoxide receptor
;
Partial agonist
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary The vascular contractile mechanism of prostacyclin (PGI2) was investigated using beraprost sodium (BPS), a stable PGI2 analog. Ring strips without endothelium isolated from canine femoral veins and arteries were used. BPS induced a dose-dependent contraction without precontraction and after precontraction with norepinephrine (NE) or 60 mM K+ in the veins. In contrast, BPS induced a dose-dependent relaxation after precontraction with U46619, a thromboxane A2 (TXA2) analog, or prostaglandin F2α (PGF2α) in the veins. In the arteries, BPS induced contraction at higher concentrations after precontraction with NE. However, BPS relaxed arteries dose-dependently after precontraction with PGF2α. By pretreatment with 13-azaprostanoic acid (13-APA), a TXA2/endoperoxide receptor antagonist, the dose-response curve of BPS in the veins was shifted to the right. Schild plot analysis resulted in a linear regression with a slope of 0.86 ± 0.13, which was not significantly different from unity, and the pA2 value for 13-APA against BPS was 7.10 ± 0.06. By pretreatment with BPS, the dose-response curve of U46619 in the veins was shifted to the right. Kaumann plot analysis resulted in a linear regression with a slope of 0.89 ± 0.09, which was not significantly different from unity, and the pA2 value for BPS against U46619 was 5.68 ± 0.04. These findings indicate that BPS is a partial agonist for the TXA2/endoperoxide receptors.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01744491
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