Characteristics of two lines of guinea pigs (BHS and BHR) differing in bronchial sensitivity to acetylcholine and histamine exposure.

In a previous study, we reported that as model animals to be used in the study of bronchial asthma in humans, two lines of guinea pigs were developed by ourselves: bronchial hypersensitive line (BHS) and bronchial hyposensitive line (BHR) as a control. Studies on biological characteristics in guinea pigs of two lines were undertaken, and the following results were obtained. 1) Airway resistance of guinea pigs of the two lines to intravenously administered acetylcholine, histamine and leukotriene D4 was found to be different between BHS and BHR. Airway resistance of BHS to the chemicals was increased compared with those of BHR. 2) The number of muscarinic acetylcholine receptors in lung membrane preparation and its affinity increased significantly in BHS compared with those of BHR. In beta-adrenergic and histamine H1 receptors, there was observed no difference between BHS and BHR. 3) No difference in IgE antibody production to ovalbumin was observed between BHS and BHR. 4) When total leukocytes and differential leukocyte count (percentage, %) in peripheral blood of BHS and BHR were examined, relative percentage of lymphocytes and eosinophils was significantly higher in BHS than in BHR, while percentage of neutrophils was significantly lower in the former than in the latter.