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Contractile endothelin-B (ETB) receptors in human small bronchi
M Adner1, L O Cardell, T Sjöberg
1Dept. of Internal Medicine, Lund University Hospital, Sweden.
The European Respiratory Journal
|February 1, 1996
Summary
Endothelins (ETs) induce contractions in small human bronchi via the ETB receptor. This study utilized improved in vitro methods to confirm ETB receptor
Area of Science:
- Pulmonary Medicine
- Pharmacology
- Respiratory Physiology
Background:
- Endothelins (ETs) are regulatory peptides crucial for pulmonary function.
- Two endothelin receptors, ETA and ETB, exist in the human lung.
- Small bronchi play a significant role in airway disease pathogenesis.
Purpose of the Study:
- To characterize the endothelin receptor mediating contraction in small human bronchi (0.5-1.0 mm diameter).
- To investigate the specific receptor subtype involved using selective agonists and antagonists.
Main Methods:
- Developed and applied improved in vitro methodology for studying small human bronchi.
- Isolated small bronchi from lung cancer patient tissue.
- Recorded isometric tension to measure contractile responses to endothelins and receptor-specific agents.
Main Results:
- ET-1, ET-2, and ET-3 induced potent, concentration-dependent contractions in small human bronchi.
- A selective ETB receptor agonist (IRL 1620) mimicked the effects of ETs.
- A selective ETA receptor antagonist (FR139317) did not inhibit ET-induced contractions, while a combined antagonist (PD 145065) did.
Conclusions:
- The study successfully employed advanced in vitro techniques for analyzing small human bronchi.
- All data strongly indicate that the ETB receptor mediates endothelin-induced contractions in human bronchi smaller than 1.0 mm.