Adrenergic airway vascular smooth muscle responsiveness in healthy and asthmatic subjects.

The purpose of the present study was to determine the responsiveness of airway vascular smooth muscle (AVSM) as assessed by airway mucosal blood flow (Qaw) to inhaled methoxamine (alpha(1)-agonist; 0.6-2.3 mg) and albuterol (beta(2)-agonist; 0.

Transient effect of inhaled fluticasone on airway mucosal blood flow in subjects with and without asthma.

Topically applied glucocorticosteroids (GS) have been shown to cause local vasoconstriction in normal skin and this phenomenon is commonly used to assess the potency of topical GS (McKenzie skin blanching test). The purpose of the present study was to determine if an inhaled GS, fluticasone propionate (FP), similarly leads to vasoconstriction in the airway mucosa and if subjects with and without asthma have differential vascular responsiveness to GS. In 10 nonsmokers with stable asthma and 10 nonasthmatic nonsmokers, airway mucosal blood flow (Qaw) expressed per milliliter of anatomical dead space and the forced expiratory volume in 1 s (FEV (1)) were determined before and serially after inhalation of FP (88 to 1,760 microg) or placebo.

Aerosolization of P2Y(2)-receptor agonists enhances mucociliary clearance in sheep.

The purpose of this study was to determine whether aerosolized INS316 (UTP) stimulates lung mucociliary clearance (MCC) in sheep and, if so, to compare its effects with INS365, a novel P2Y(2)-receptor agonist. In the first series of studies, we used a previously described roentgenographic technique to measure tracheal mucus velocity (TMV), an index of MCC, before and for 4 h after aerosolization of INS316 (10(-1) M and 10(-2) M) and INS365 (10(-1) M and 10(-2) M), or normal saline in a randomized crossover fashion (n = 6). In a second series of studies, we compared the ability of these agents to enhance total lung clearance.

Effect of inhaled and intravenous acetylcholine on bronchial blood flow in anesthetized sheep.

The reported effects of cholinergic agonists on bronchial blood flow (Qbr) have been inconsistent. The aim of the present study was to determine whether the inconsistency could be due to the mode of agonist administration (systemic vs. aerosol) or the anatomic site of blood flow in the bronchus (mucosal vs.

Enhanced aerosol deposition in the lung with mild airways obstruction.

We investigated the sensitivity of aerosol deposition to airways obstruction by measuring total deposition fraction of inert aerosol in normal conscious sheep (n = 6) after challenging cholinergic agent, pilocarpine (PL) (0.5 mg/kg intravenously) with and without a prior challenge of beta 2-adrenergic agonist, terbutaline sulfate (TS) (0.025 mg/kg subcutaneously).