In Vitro Exposure to Nitrogen Dioxide (NO2) Does Not Alter Bronchial Smooth Muscle Responsiveness in Ovalbumin-sensitized Guinea-pigs
✍ Scribed by P. Chitano; E. Coser; R.E. Lucchini; A. Papi; M. Saetta; P. Maestrelli; D. Faggian; M. Plebani; A. Ciaccia; L.M. Fabbri; C.E. Mapp
- Publisher
- Elsevier
- Year
- 1994
- Tongue
- English
- Weight
- 421 KB
- Volume
- 7
- Category
- Article
- ISSN
- 0952-0600
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✦ Synopsis
SUMMARY: The aim of this study was to investigate whether in vitro exposure to (\mathrm{NO}{2}) affects responsiveness in ovalbumin-sensitized guinea-pig bronchi. Twenty-three animals were sensitized by three weekly intraperitoneal injections of (1 \mathrm{mg}) ovalbumin in saline with Freund's adjuvant; twenty-one control guinea-pigs received the diluent alone. From each animal, the two main bronchi were obtained and cannulated, then exposed in vitro to a constant intraluminal flow of: (i) either air or (2.5 \mathrm{ppm} \mathrm{NO}{2}) with four spikes of (10 \mathrm{ppm} \mathrm{NO}{2}) for (2 \mathrm{~h}); (ii) either air or (10 \mathrm{ppm}) (\mathrm{NO}{2}) for (4 \mathrm{~h}). A bronchial ring obtained from each animal before exposure was kept in aerated Krebs-Henseleit solution. Rings from bronchi exposed to air, (\mathrm{NO}{2}), or kept in Krebs solution were studied isometrically. We performed overall and non-adrenergic non-cholinergic voltage-response curves to electrical field stimulation, concentration-response curves to acetylcholine and to neurokinin (A), followed by administration of (10 \mathrm{mg} / \mathrm{ml}) ovalbumin. We did not find any significant difference in bronchial smooth muscle responsiveness between nonexposed, air-exposed and (\mathrm{NO}{2})-exposed bronchi, as well as between bronchi from control and sensitized animals. We conclude that in vitro exposure to (\mathrm{NO}_{2}) does not alter bronchial smooth muscle responsiveness to either specific or non-specific stimuli.