To examine the effect of nonadrenergic noncholinergic (NANC) inhibitory nerve stimulation on the antigen inhalation with allergic animals, changes in pulmonary resistance (RL) and arterial plasma histamine concentration ([H]) caused by inhalation of Ascaris suum antigen were studied in five control (Group A) and five nerve-stimulated (Group B) cats, which were anesthetized and mechanically ventilated. All animals were actively sensitized with Ascaris antigen before the experiment. After cholinergic and β-adrenergic blockade with intravenously administered atropine (3 mg/kg) and propranolol (2 mg/kg), inhalation of the antigen (1:100 dilution) was performed for 3 min. for Group B, bilateral cervical vagi were stimulated electrically for 1 min before the antigen inhalation and successively every 30 s until 5 min had passed from the onset of inhalation. RL and [H] were determined before, during, and after antigen inhalation in both groups. Baseline RL and [H] did not differ significantly between groups (16.3 ± 2.2 (mean ± SE) cm H2O/L/s and 14.0 ± 0.7 ng/ml, respectively, for Group A; 14.4 ± 1.3 and 15.6 ± 2.7, respectively, for Group B). Increases in RL and [H] of Group B after the antigen inhalation were significantly depressed, compared with Group A (p < 0.01 and p < 0.05, respectively, two-way ANOVA). The increase in RL 5 min after antigen inhalation was 113 ± 19% for Group A and 28 ± 8% for Group B, and the increase in [H] at the same point was 36.3 ± 9.1 ng/ml for Group A and 4.4 ± 1.4 ng/ml for Group B. Further, increases in RL and [H] 5 min after antigen inhalation were significantly correlated (r = 0.80, p < 0.01). These results suggest that stimulation of NANC inhibitory nerves have the potentiality to depress the allergic reaction in the airways.
ASJC Scopus subject areas
- Pulmonary and Respiratory Medicine