Related Experiment Videos
Glibenclamide inhibits thromboxane-mediated vasoconstriction by thromboxane receptor blockade
Sandra L Pfister1, Philip E Pratt, Joseph Kurian
1Department of Pharmacology and Toxicology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA. spfister@mcw.edu
Vascular Pharmacology
|April 6, 2004
Summary
Glibenclamide, used for Type 2 diabetes, directly blocks the thromboxane (TX) receptor in blood vessels. This action inhibits TX-mediated contractions, offering new insights into cardiovascular complications.
Area of Science:
- Cardiovascular Pharmacology
- Endocrinology
- Molecular Biology
Background:
- Type 2 diabetes is linked to cardiovascular issues, potentially involving thromboxane (TX).
- Glibenclamide is a common sulfonylurea medication for Type 2 diabetes.
- Understanding glibenclamide's vascular effects is crucial for managing diabetic complications.
Purpose of the Study:
- To investigate the effect of glibenclamide on TX-mediated vascular contractions.
- To determine if glibenclamide's action involves the TX receptor or vascular K(ATP) channels.
Main Methods:
- Isolated bovine coronary arteries and rabbit aortas were used to study vascular contractions.
- Vessels were contracted using TXA(2) analogs, endothelin, and phenylephrine.
- Receptor binding assays were performed on rabbit vascular smooth muscle cells to assess glibenclamide's interaction with the TX receptor.
Main Results:
- Glibenclamide (10 microM) significantly inhibited contractions induced by TXA(2) analogs.
- Glibenclamide did not affect contractions induced by endothelin or phenylephrine.
- Glibenclamide inhibited (125)I-BOP binding to the TX receptor by over 80% in rabbit vascular smooth muscle cells, with an inhibition constant (Ki) of 0.53 microM.
Conclusions:
- Glibenclamide directly blocks the vascular TX receptor.
- This blockade of the TX receptor is independent of vascular K(ATP) channel activity.
- Glibenclamide's inhibition of TX-mediated contractions is a key mechanism relevant to diabetic cardiovascular complications.