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Critical Care

, 9:P92 | Cite as

Effect of beta-adrenergic agonist on alveolar fluid clearance in rats

  • H Qiu
  • Y Yang
  • H Sun
Poster presentation

Keywords

mRNA Expression Emergency Medicine Atenolol Specific Inhibitor Dobutamine 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Objective

To investigate the effect and the associated mechanism of beta-adrenergic agonist on alveolar fluid clearance (AFC) in rats.

Methods

Forty-eight Sprague–Dawley male rats were randomly divided into six groups (normal control group, dobutamine group, amiloride [specific inhibitor of epithelial sodium channel] group, dobutamine + amiloride group, dobutamine + atenolol [specific beta-1 antagonist] group, dobutamine + ICI118,551 [specific beta-2 antagonist] group). AFC was measured by the single-nuclide tracer technique. Alpha-rat epithelial sodium channel (alpha-rENaC), beta-rENaC and gamma-rENaC mRNA expressions were measured by RT-PCR.

Results

(1) AFC of the dobutamine group and dobutamine + atenolol group were 26.6 ± 1.6% and 25.0 ± 5.3%, respectively, which were significantly higher than the normal control group (21.0 ± 3.9%) and dobutamine + ICI 118,551 group (21.0 ± 4.8%) (P < 0.05). There was no significant difference of AFC between the dobutamine group and dobutamine + atenolol group (P > 0.05); and no significant difference of AFC between the normal control group and dobutamine + ICI 118,551 group (P > 0.05). (2) AFC of the amiloride group was 6.0 ± 2.8%, which was significantly lower than the normal control group (P < 0.05). (3) AFC of the dobutamine + amiloride group was 10.0 ± 2.3%, significantly higher than the amiloride group (P < 0.05). (4) Gamma-rENaC mRNA expression of the dobutamine group and dobutamine + atenolol group was 0.90 ± 0.19 and 0.90 ± 0.09, respectively, significantly higher than the normal control group (0.69 ± 0.09) and dobutamine + ICI 118,551 group (0.68 ± 0.06) (P < 0.05). There was no significant difference of gamma-rENaC mRNA expression between the dobutamine group and dobutamine + atenolol group; and no significant difference of gamma-rENaC mRNA expression between the normal control group and dobutamine + ICI 118,551 group (P < 0.05). There was no significant difference of alpha-rENaC and beta-rENaC mRNA expressions between each group (P > 0.05). (5) Gamma-rENaC mRNA expression of the dobutamine + amiloride group was 0.70 ± 0.14, significantly lower than the dobutamine group and dobutamine + atenolol group (P < 0.05).

Conclusion

The amiloride-sensitive NaC pathway was important for lung epithelium to actively transport alveolar fluid. The effect of beta-2 adrenergic stimulation may upregulate gamma-rENaC expression and also stimulate the amiloride-insensitive NaC pathway to improve AFC in rats.

Copyright information

© BioMed Central Ltd 2005

Authors and Affiliations

  • H Qiu
    • 1
  • Y Yang
    • 1
  • H Sun
    • 1
  1. 1.Nanjing Zhong-Da HospitalSoutheast UniversityNanjingChina

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