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Acute induction of tracheo-bronchoconstriction in morphine/chloralose anesthetized dogs: physiological approach and principles of therapy

Al Wabel, Naser Ali
http://rave.ohiolink.edu/etdc/view?acc_num=osu1069557474

Abstract Details

2003, Doctor of Philosophy, Ohio State University, Veterinary Biosciences.
The respiratory system serves as a functional gas exchanger which, under neural control, contributes greatly to homeostasis. This study was designed to evoke tracheo-bronchoconstriction by different stimuli and to study the respiratory and hemodynamic effects of three bronchodilators. Tracheo-bronchoconstriction was induced in morphine/chloralose-anesthetized dogs by 5% CO2, 10% O2 or intravenous bethanechol (0.5 mg/kg). Hypercapnia caused no significant (p>0.01) respiratory or hemodynamic effects. Hypoxia significantly (p<0.01) increased heart rate (HR), pulmonary artery pressure (Pap), cardiac output (CO), and peripheral vascular resistance (PVR). No significant changes were observed in left ventricular end-diastolic pressure (LVEDP), tracheal pressure (Tp), airway pressure (Paw), bronchial pressure (Brp), and pulmonary compliance (PC) due to hypoxia. Changes due to gas mixtures were transient and returned to baseline upon normal respiration. In contrast, bethanechol caused significant increases in Pap, LVEDP, PVR, Tp and Paw with no significant changes in HR, CO or Brp. Compared to gas mixtures, bethanechol produced greater respiratory and hemodynamic effects that may resemble asthma and chronic obstructive pulmonary disease. Four groups of dogs were used to compare the respiratory and hemodynamic effects of aminophylline, atropine, terbutaline, or saline control on bethanechol-induced bronchoconstriction. Both atropine (0.04 mg/kg) and aminophylline (20 mg/kg) increased HR significantly (p<0.006) compared to control. Atropine, starting at 0.02 mg/kg, significantly decreased the bethanechol-elevated Pap, with no changes in the other groups. Atropine (0.02 mg/kg) and aminophylline (20 mg/kg) significantly decreased LVEDP after bethanechol. Atropine decreased 65% of the elevated Tp compared to 47%, and 12.6% for terbutaline, and aminophylline, respectively. Only terbutaline significantly decreased Paw and increased PC. No significant changes were observed in CO, PVR, Brp, or in blood and end-tidal gases after any bronchodilator. The high efficacy of atropine in reversing bethanechol-induced tracheo-bronchial spasm suggests a dominant control of respiration by the parasympathetic system. With limitations, this model might be of benefit in evaluating the mechanism of other bronchodilators that alter autonomic nervous control, such as M3-selective antimuscarinics.
Dr. Robert Hamlin (Advisor)
Dr. S. Strauch (Other)
Dr. Kathryn Meurs (Other)
Dr. Roger Stradley (Other)
175 p.
Tracheo-bronchoconstriction; Bethanechol; Bronchodilators; Morphine/chloralose; Dog; Asthma; COPD; Hemodynamic

Recommended Citations

Citations

  • Al Wabel, N. A. (2003). Acute induction of tracheo-bronchoconstriction in morphine/chloralose anesthetized dogs: physiological approach and principles of therapy [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1069557474

    APA Style (7th edition)

  • Al Wabel, Naser. Acute induction of tracheo-bronchoconstriction in morphine/chloralose anesthetized dogs: physiological approach and principles of therapy. 2003. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1069557474.

    MLA Style (8th edition)

  • Al Wabel, Naser. "Acute induction of tracheo-bronchoconstriction in morphine/chloralose anesthetized dogs: physiological approach and principles of therapy." Doctoral dissertation, Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1069557474

    Chicago Manual of Style (17th edition)

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This open access ETD is published by The Ohio State University and OhioLINK.