No abstract

The effect on airway conductance (Gaw) and functional residual capacity (FRC) of stimulation of cold receptors in facial skin was studied in 12 healthy young subjects, with a body plethysmograph. Mean Gaw decreased significantly, from 0.44 to 0.38 liter s−1 cm−1 H2O, in 10 subjects. FRC was only slightly affected, probably because the experiment was too brief to allow air-trapping. It is concluded that the Gaw decrease during exposure to cold results from bronchoconstriction due to (a) stimulation of trigeminal nerve cold receptors and to (b) pharyngeal and glottal airway resistance increase resulting from frequent involuntary 'dry' swallowing.

Rats and hamsters were exposed to thesmoke of unfiltered cigarettes for prolonged periods. The results indicated that the smoke-exposed animals were smaller than their corresponding control mates. In addition, the exposed animals demonstrated a larger variety of mucociliary abnormalities including zones of ciliary inactivity, disturbance of the coordination of ciliary movement, impaired mucus production and altered rheological characteristics of mucus. The possible relationship to chronic bronchitis is discussed

The effects of a number of drugs, potassium and calcium ions, and air humidity on mucociliary function were studied in isolated preparations of rats bronchial tree. Adrenergic drugs increased the rate of ciliary beat significantly. Cilioexitation also occurred, though to a smaller degree, after application of acetylcholine, pilocarpine, aminophylline, prednisolone, KI and NH₄CI. Serotonin, histamine, and acetylcystein did not change ciliary frequency to any significant degree; however, histamine in high concentrations caused ciliary incoordination. Codein and normetadon, nicotine and pentobarbital had a dose-dependent ciliodepressive effect. However, small concentrations of nicotine and pentobarbital were slightly stimulative. Methysergid and phentolamine were slightly ciliodepressive. Alterations of the concentrations of calcium and potassium ions in the nutritive solution influenced ciliary frequency but had no effect on other characteristic features of the ciliary movement. The ciliated epithelium of the bronchial tree could be irreversibly damaged by air having low relative humidity.

The influence of drugs on ciliary beat frequency in the intrapulmonary airways of rats was studied in vitro. Sympathomimetic drugs significantly increased the ciliary beat frequency. Acetylcholine, pilocarpine, aminophylline, prednisolone, potassium iodide, and ammonium chloride also caused cilioexcitation, though to a lesser degree. Phentolamine, 5-hydroxytryptamine, histamine, and acetylcysteine caused an apparent cilioinhibition. However, histamine in high doses also caused an incoordination of ciliary beat. Codeine and phenobarbital were slightly cilioexcitatory in low concentrations and ciliodepressive at higher concentrations.