Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0242706 (hyperoxia)
 5,219 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ability of atrial natriuretic peptide, salbutamol, sodium nitroprusside and isosorbide dinitrate to protect against challenge with methacholine in bovine isolated bronchi was compared in different O2 tensions. Perfusing the Krebs-Henseleit solution with gas mixtures containing 95% O2 (hyperoxia), 20% O2 (approximately normoxia) and 0% O2 (hypoxia) produced O2 tensions in the organ-baths of 524, 147 and 26 mm Hg, respectively. In hyperoxia, pre-incubation of atrial natriuretic peptide at concentrations of 3 x 10(-7) M and 10(-6) M significantly attenuated responses to methacholine, whereas in normoxia, these concentrations of atrial natriuretic peptide had no effect. Furthermore, in hypoxia, 3 x 10(-7) M and 10(-6) M atrial natriuretic peptide significantly enhanced responses to methacholine. Salbutamol, at concentrations of 3 x 10(-7) M and 10(-6) M significantly attenuated responses to methacholine in hyperoxia, whereas in normoxia and hypoxia, pre-incubation of salbutamol did not alter the methacholine response. Pre-incubation of 10(-5) M sodium nitroprusside significantly attenuated methacholine-induced contractions in hyperoxia and when the oxygen tension in the gas mixture was lowered to 20% or 0%, the ability of sodium nitroprusside to protect against methacholine challenge was enhanced. In hyperoxia, isosorbide dinitrate, at the 10(-4) M level, evoked a rightward shift of the methacholine response curve. Lowering the oxygen tension to either 20% or 0% enhanced the protectant effect of isosorbide dinitrate, with the effect being greater in 20% O2. Thus, the effect of these bronchodilators on methacholine-induced challenge in hyperoxia O2 differed from those in normoxia and hypoxia, although the direction of the changes varied among the agents used. This suggests that the responses evoked by bronchodilators in 95% O2 may not necessarily predict those in the physiological range of oxygen tensions and that the relative effectiveness of bronchodilators may vary between normoxic and hypoxic conditions.
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PMID:Changing the oxygen tension alters the ability of bronchodilators to protect against methacholine-induced challenge in bovine isolated bronchial rings. 934 33

The aim of the present study was to investigate the in vitro effects of the short-acting beta2-adrenoceptor agonist salbutamol and the long-acting beta2-adrenoceptor agonist salmeterol on hypoxia-induced rat diaphragm force reduction. In vitro diaphragm twitch force (Pt) and maximal tetanic force (Po) of isolated diaphragm muscle strips were measured for 90 min during hyperoxia (tissue bath PO2 83.8 +/- 0.9 kPa and PCO2 3.9 +/- 0.1 kPa) or severe hypoxia (PO2 7.1 +/- 0.3 kPa and PCO2 3.9 +/- 0.1 kPa) in the presence and absence of 1 microM salbutamol or 1 microM salmeterol. During hyperoxia, salbutamol and salmeterol did not significantly alter the time-related decreases in Pt and Po (to approximately 50% of initial values). Salbutamol had no effects on Po or the Pt-to-Po ratio. Salmeterol treatment significantly reduced Po and increased the Pt-to-Po ratio during hyperoxia (P < 0.05 compared with control value). Hypoxia resulted in a severe decrease in Pt (to approximately 30% of initial value) and Po after 90 min. Both salbutamol and salmeterol significantly reduced the decline in Pt during hypoxia (P < 0.05). The reduction in Po was not prevented. Salbutamol increased Pt rapidly but transiently. Salmeterol had a delayed onset of effect and a longer duration of action. Addition of 1 microM propranolol (a nonselective beta-adrenoceptor antagonist) did not alter Pt, Po, or the Pt-to-Po ratio during hypoxia but completely blocked the inotropic effects of salbutamol and salmeterol, indicating that these effects are dependent on beta2-adrenoceptor agonist-related processes.
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PMID:beta2-adrenoceptor agonists reduce the decline of rat diaphragm twitch force during severe hypoxia. 1007 Jan 12