Influence of resting tension on protease-activated receptor-mediated relaxation in guinea-pig tracheas
| Autor: | Lucilla Zilletti, S. Franchi-Micheli, Mirian Cantore, Paola Failli, Luca Mazzetti, M. Ciuffi |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Male
Pulmonary and Respiratory Medicine medicine.medical_specialty Vasodilator Agents Guinea Pigs Nitric Oxide Dinoprostone Hemostatics Nitric oxide chemistry.chemical_compound Adenosine Triphosphate Thrombin Isometric Contraction Internal medicine medicine Animals Receptor PAR-2 Cyclooxygenase Inhibitors Trypsin Pharmacology (medical) Protease-activated receptor Enzyme Inhibitors Receptor Dose-Response Relationship Drug biology Biochemistry (medical) Muscle Smooth Type 2 protease activating receptor agonist peptide Prostaglandin E2 Adenosine Acetylcholine Trachea Nitric oxide synthase NG-Nitroarginine Methyl Ester Endocrinology chemistry biology.protein Cyclooxygenase medicine.drug |
| Zdroj: | Pulmonary Pharmacology & Therapeutics. 18:141-150 |
| ISSN: | 1094-5539 |
| DOI: | 10.1016/j.pupt.2004.11.006 |
| Popis: | We investigate the role of resting tension on thrombin (THR) induced relaxation of guinea-pig tracheas precontracted with acetylcholine (ACh). Isometric contractions of isolated guinea-pig tracheas were recorded at 4 and 6 g resting tension; and ACh dose–response curves were performed. THR relaxed ACh-precontracted tracheas and this effect was mimicked by the type 2 protease activating receptor agonist peptide (PAR-2 AP) and trypsin. The relaxant effect of 3 U ml −1 THR and 100 nmol ml −1 PAR-2 AP was prevented at 4 g by preincubation with the nitric oxide synthase (NOS) inhibitor l -NAME and at 6 g resting tension by ibuprofen and diclofenac. However, adenosine trisphospahate (ATP) relaxation was totally prevented by cyclooxygenase (COX) inhibitors but not by NOS inhibitors at both resting tensions. Resting tension influenced the effect of PGE 2 on contractile tone of isolated guinea-pig tracheas, the maximal relaxation being −11.1±2.97 and −2.0±0.46 mg mg −1 tissue wet weight at 6 and 4 g, respectively. Moreover, 30 nmol ml −1 PGE 2 can relax ACh-precontracted tracheas, being the effect up to 91 and 30% at 6 and 4 g, respectively. These data demonstrate that trachea responsiveness is highly dependent on the smooth muscle length, revealing new aspects of stretch-activated receptors that can influence trachea responsiveness in vivo. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect