Bronchial response to methacholine and histamine in monkeys with beta adrenergic blockade

The possibility has been investigated that propranolol administration could alter bronchial reactivity to methacholine and histamine in monkeys (Macaca fuscata and Macaca fascicularis). The impedance of the total respiratory system was measured by the forced 3-HZ oscillation method through an endotracheal tube. Methacholine and histamine dose-dependently increased the impedance in monkeys irrespective of the route of administration (inhalation of aerosol or intravenous injection). Propranolol treatment increased the bronchial response to intravenously injected methacholine and caused no significant change in the bronchial response to aerosolized methacholine. No marked difference was observed in the bronchial response to histamine due to treatment with propranolol regardless of whether administered by intravenous injection or aerosol challenge.