Related Experiment Video
Updated: Sep 8, 2026

In Vitro and In Vivo Model to Study Bacterial Adhesion to the Vessel Wall Under Flow Conditions
Published on: June 11, 2015
Thromboxane A2 and prostaglandin endoperoxide receptors in platelets and vascular smooth muscle
Abstract:
9,11-Dimethylmethano-11,12-methano-16-(3-iodo-4-hydroxyphenyl)-13, 14-dihydro-13-aza-15 alpha beta-omega-tetranor-TXA2 (I-PTA-OH), a recently synthesized thromboxane (TX) A2/prostaglandin (PG) H2 receptor antagonist, was shown to be a competitive antagonist of human platelet aggregation induced by the stable endoperoxide analog U46619. This antagonism was due to competitive blockade of the platelet TXA2/PGH2 receptor since I-PTA-OH did not antagonize the first phase of ADP-induced aggregation which is TXA2/PGH2 independent, nor did it inhibit TXA2 synthesis. In addition, analysis of dose-response curves to U46619 (0.1 to 40 microM) in the presence of increasing concentrations of I-PTA-OH (0.5 to 10 microM) showed that I-PTA-OH produced a parallel rightward shift of the dose-response curve. Further analysis of the data in the form of a Schild plot yielded a straight line with a slope (m = 1.03) not significantly different from -1. These results are consistent with the notion that I-PTA-OH acts as a competitive antagonist of the TXA2/PGH2 receptor.
Related Concept Videos
Adrenergic Receptors: ɑ Subtype
Adrenaline ≥ Noradrenaline >> Isoprenaline
α-adrenoceptors are further divided into α1 and α2-adrenoceptors.
α1-Adrenoceptors: These receptors are located postsynaptically on the effector organs and cause constriction of smooth muscle mediated by activation of phospholipase C—inositol-1,4,5-trisphosphate...
Antiplatelet Drugs: Prostaglandin Synthesis, P2Y12 and Glycoprotein IIb/IIIa Inhibitors
Prostaglandin synthesis inhibitors, exemplified by the widely known aspirin, wield their power by irreversibly acetylating...
Vascular Spasm
Formation of the Platelet Plug
As the injured blood vessel contracts, endothelial cells undergo contraction, revealing collagen fibers in the basement membrane and underlying connective tissue. Furthermore, the plasma membrane of endothelial cells becomes adhesive, preparing the site for platelet adhesion. Platelets...
Clot Retraction and Fibrinolysis
Treatment for Pulmonary Arterial Hypertension: Prostacyclin Receptor Agonists
These agonists bind to the IPR receptor situated on the plasma membrane of the pulmonary artery smooth muscle cells. This binding triggers a cascade of reactions known as the GS-AC-cAMP-PKA pathway. This pathway results in the relaxation of smooth muscle...

