Morton S. Skorodin

Role of the Parasympathetic System in Airway Obstruction Due to Emphysema

To study the relative contributions of parasympathetic and sympathetic mechanisms in airway obstruction in patients with emphysema, we gave supramaximal doses of anticholinergic and adrenergic agents in sequence and in combination. Serial doses of one agent were administered to achieve a plateau of bronchodilatation; after that the other agent was administered. The plateau achieved with the anticholinergic agent (atropine methonitrate) was significantly higher than that achieved with the adrenergic agent (salbutamol). When the adrenergic agent was given first, additional bronchodilatation was achieved with subsequent use of the anticholinergic agent. When the anticholinergic agent was given first, no additional bronchodilatation was achieved with subsequent administration of the adrenergic agent. When both agents were given simultaneously, the degree of bronchodilatation was virtually identical to that obtained with the anticholinergic agent alone. Tests sensitive to small-airway and large-airway function and lung volumes gave essentially the same results. Thus, all achievable bronchodilatation was obtained with the anticholinergic agent alone. These results suggest that the two classes of agents produce bronchodilatation through a common cholinergic pathway in emphysema, and support the concept that parasympathetic activity is the dominant reversible component of airway obstruction in this disease.

Effects of Oral Albuterol on Serum Lipids and Carbohydrate Metabolism in Healthy Men

beta(2)-Selective adrenergic agonists are used in the management of bronchial asthma and preterm labor. Due to their ability to increase muscle strength and size in animal models, new applications for these agents are also being explored for neuromuscular disorders and in rehabilitation. However, the effects of long-term beta(2)-agonist administration on lipoprotein and carbohydrate metabolism are incompletely understood. This investigation evaluated the effects of a beta(2)-agonist, albuterol, on serum lipids and carbohydrate homeostasis in eight healthy nonsmoking men aged 24 to 61 years. Collection of fasting blood samples was completed in duplicate on separate days at baseline, during 14 days of oral albuterol administration (Proventil Repetabs, 8 mg twice daily; Schering Pharmaceuticals, Kenilworth, NJ) and during a 7-day washout period. Carbohydrate homeostasis was evaluated using the minimal model technique at the end of the baseline and albuterol periods. Fasting glucose and insulin, intravenous glucose tolerance, acute insulin response to intravenous glucose (AIRg), insulin sensitivity (Si), and glucose effectiveness (Sg) were not significantly changed during albuterol administration. Significant alterations (P < or = .02) were observed in total cholesterol ([TC] -9.1% +/- 2.5%), low-density lipoprotein cholesterol ([LDL-C] -15.0% +/- 2.9%), and high-density lipoprotein cholesterol ([HDL-C] +10.4% +/- 3.2%) concentrations, as well as the TC/HDL-C (-17.4% +/- 2.6%) and LDL-C/HDL-C (-22.9% +/- 2.4%) ratios. During washout, TC and LDL-C returned to baseline levels, whereas HDL-C remained elevated by 5.8% +/- 2.4% (P < .05). Thus, albuterol administration was associated with favorable changes in the serum lipid profile without marked impairment of glucose tolerance or its physiologic determinants.