The control of airway mucus secretion.

Airway mucus is essential for the effectiveness of cough and mucociliary transport. Even the resting airway produces some mucus but, under a great variety of threats to airway function, this production increases. A number of mechanisms may be responsible for augmenting secretion; these include reflexes, initiated by nervous receptors in the airways, and with their efferent limbs in the autonomic nerves to the airways.

The effect of airflow on mucus secretion into the trachea of the cat.

We have investigated the effects of the passage of air and of instillation of hyperosmolal solutions in a segment of trachea of the pentobarbitone-anaesthetized cat on the release of radiolabelled mucus glycoproteins (mucins) into that segment. Ambient air passed through the segment at 11 min-1 increased the output of both 35S- and 3H-labelled mucins. It also stimulated the output of mucins measured chemically.

The effect of tobacco smoke upon airway secretion in the cat.

We have collected secretions from a segment of trachea in the neck of cats anaesthetized with chloralose. At the start of experiments sodium [35S]sulphate and [3H]glucose were given into the segment to radiolabel secretions by biosynthesis. Subsequently, changes in output of radiolabelled macromolecules were used to indicate changes in mucin secretion rate.

Nervous control of mucin secretion into human bronchi.

Pieces of ferret trachea and human bronchi were mounted in Ussing chambers and given [35S]sulphate as a radiolabelled precursor of mucous glycoproteins (mucins). The output of 35S bound to macromolecules was studied as an index of mucin secretion. In the ferret trachea, electrical field stimulation increased the rate of mucin secretion.

Effects of prostaglandins E1, E2, and F2 alpha on mucin secretion from human bronchi in vitro.

The effects of three prostaglandins on the output of 35S labelled mucus glycoproteins (mucins), from explants of human bronchial tissue suspended in Ussing chambers, have been investigated. Prostaglandin F2 alpha, added to the Krebs-Henseleit solution bathing both luminal and submucosal sides of the tissue, significantly increased mucin output at concentrations of 0.1 and 1.