Research Abstract |
1. Alcohol-induced bronchoconstriction in guinea pigs (1) Acetaldehyde, a metabolite of ethanol, causes bronchoconstriction but ethanol does not. (2) The acetaldehyde-induced bronchoconstriction is mediated via histamine release. (3) A low dose of acetaldehyde, which does not cause bronchoconstriction, enhances non-specific bronchial responsiveness. (4) Thromboxane A2 is involved in the acetaldehyde-induced non-specific bronchial hyperresponsiveness. 2. A guinea big model of propranolol-induced bronchoconstriction and the role of autonomic nerve system, chemical mediators and neuropeptides (1) An inhalation of propranolo causes bronchoconstriction when it is inhaled 20 minutes after an aerosolized antigen provocation in passively sensitized guinea pigs. This is the first animal model or propranolol-induced bronchoconstriction. (2) Parasympathctic or alpha-adrenergic nerve activity is not involved in this response. (3) Ncuropeptides such as substance P and neurokinin A do not take a part in this
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response. (4) Lipid mediators, especially thromboxane A2, have an important role in this response. 3. A guinea-pig model of untrasonically nebulized distillled water (UNDW) -induced bronchoconstriction and the role of autonomic nerve system, chemical mediators and neuropeptides (1) An inhalation of UNDW produces acute bronchoconstriction when it is inhaled 20 mimutes after an aerosolized antigen provocation in passively sensitized guinea pigs. This is the first animal model of UNDW-induced bronchoconstriction. (2) Parasympathetic nerve activity is not involved in this response. (3) Histamine and substance P,but not neurokinin A,take a large part in this response. (4) Thromboxane A2 does not have a role in this response. 4. Conclusion Form these results, it is suggested that allergic airway response, or allergic airway inflammatory process, is important in development of specific bronchial responsiveness. Furthermore, the mechanism of specific bronchial hyperresponsiveness may be different each other, suggesting heterogeneity of contributing factors between several specific bronchial hyperresponsiveness in asthma. Less
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