an antagonistic hormone
No. Aspirin prevents the synthesis of Thromboxane A2 which induces platelet aggregation (formation of a clot) and platelet release reaction. Aspirin inhibits this platelet aggregation for the life of the platelets, which is between 7-10 days. The cool thing with aspirin is that it thins your blood, the bad thing is that it thins your blood and if you want to stop taking aspirin (for any reason, even before surgery) you have a 3x increase of stroke or heart attack for 8-10 days because of its rebound effect. Aspirin is a light-weight compared to Heparin or Coumadin, but Heparin is easily reversed with Protamine-sulfate solution 1% and Coumadin with Vitamin K - something to think about. Maybe one day a drug will be created to reactivate Thromboxane A2 synthesis, but not yet. Trust your PA-C's.
The only difference between vitamin A1 and A2 is of a bond in the ring.
Viscosity opposes the motion of an object through liquid.
The "strong nuclear force" does.
3
antidepressants and smoking
Adenosine diphosphate (ADP), Serotonin, and thromboxane A2
It decreases synthesis of thromboxane A2 and prostaglandins to increase bleeding time. It does not affect PT or PTT. Prothrombin time unaffected!
an antagonistic hormone
They are synthesized in the cell from the essential fatty acids (EFAs). An intermediate arachidonic acid is created from diacylglycerol via phospholipase-A2, then brought to either the cyclooxygenase pathway or the lipoxygenase pathway to form either prostaglandin and thromboxane or leukotriene respectively. The cyclooxygenase pathway produces thromboxane, prostacyclin and prostaglandin D, E and F. Alternatively, the lipoxygenase enzyme pathway is active in leukocytes and in macrophages and synthesizes leukotrienes. Dr.Fabianski Benjamin
Thromboxane is a potent platelet agregator
A antagonist muscle is a muscle that opposes the action of another muscle. The Triceps Brachii is the antagonist of the Biceps Brachii.
Ad hominem
More correctly it is called antiplatelet aggregation drugs (also called antithrombotic drugs) that include aspirin, clopidogrel, abciximab (monoclonal antibodies) and GPII/ IIIA receptors antagonists etc. Each drug has its own way and mechanism of action. It depends upon chemical structure of drug and site of action. Aspirin blocks aggregation by inhibiting cycloxygenase that produce thromboxane A2 that causes platelet aggregation. Clopidogrel acts as antagonist to P2Y2 receptors present on platelets required for their aggregation. You can check for further details. Umar Mujahid Pharm.D u.mujahid@yahoo.com
A antagonist muscle is a muscle that opposes the action of another muscle. The Triceps Brachii is the antagonist of the Biceps Brachii.
Calcitonin opposes the action of parathyroid hormone.