Estimation of thickness of airway surface liquid in ferret trachea in vitro.

The tracheae of ferrets and rabbits were mounted in vitro in organ baths. While the tracheae were liquid filled, the permeability coefficient ( P) was determined, and then while the tracheae were air filled, the percent clearance for 99mTc-labeled diethylenetriaminepentaacetic acid (DTPA) was determined. The thickness of airway surface liquid (ASL) was estimated by three methods.

H2O2 increases sheep tracheal blood flow, permeability, and vascular response to luminal capsaicin.

Exogenous hydrogen peroxide (H2O2) causes airway epithelial damage in vitro. We have studied the effects of luminal H2O2 in the sheep trachea in vivo on tracheal permeability to low-molecular-weight hydrophilic (technetium-99m-labeled diethylenetriamine pentaacetic acid; 99mTc-DTPA) and lipophilic ([14C]antipyrine; [14C]AP) tracers and on the tracheal vascular response to luminal capsaicin, which stimulates afferent nerve endings. A tracheal artery was perfused, and tracheal venous blood was collected.

Sodium metabisulphite causes epithelial damage and increases sheep tracheal blood flow and permeability.

Inhaled sodium metabisulphite (MBS) causes bronchoconstriction, cough and microvascular leakage. We have studied its effects on tracheal blood flow, potential difference (PD) and the permeability from tracheal lumen to venous blood of a low molecular weight hydrophilic tracer, 99mtechnetium-labelled diethylenetriamine penta-acetic acid (99mTc-DTPA) in anaesthetized sheep. Flow was measured in tracheal artery and blood from a cannulated tracheal vein collected for 5 min periods.

Tracheal epithelial damage alters the effects of luminal histamine on blood flow and tracer flux in anaesthetized sheep.

Epithelial damage greatly increases the flux of a low molecular weight tracer 99mtechnetium-diethylenetriamine penta-acetic acid (99mTc-DTPA) from tracheal lumen to venous-blood in anaesthetized sheep. We have now investigated whether epithelial damage induced by the detergent, Triton X-100, alters the effects of luminal histamine on blood flow and 99mTc-DTPA flux. The cervical trachea was filled with Krebs-Henseleit solution containing 99mTc-DTPA.

Tracheal epithelial damage alters tracer fluxes and effects of tracheal osmolaity in sheep in vivo.

Tracheal osmolaity affects blood flow and the flux of a tracer, technetium-99m-labeled diethylenetriamine pentaacetic acid (99mTc-DTPA), from tracheal lumen to venous blood in anesthetized sheep. Hyperosmolar liquids increase blood flow and slightly decrease 99mTc-DTPA flux, whereas hyposmolar liquids have no effect on blood flow and greatly increase 99mTc-DTPA flux. We have now investigated whether epithelial damage induced by exposure of the tracheal lumen to a detergent (0.

Osmolality alters tracheal blood flow and tracer uptake in anesthetized sheep.

Changes in the osmolality of airway surface liquid cause bronchoconstriction, mucus secretion, and ion transport, but little is known about the effects on the permeability of the trachea to drugs applied to the tracheal lumen. Using the anesthetized sheep, we have investigated the effects of hyperosmolar (725 +/- 11 mosmol/kg) and hyposmolar (128 +/- 5 mosmol/kg) Krebs-Henseleit (KH) solution in the tracheal lumen (mean volume 13.6 ml) on the uptake of technetium-99m-labeled diethylenetriamine pentaacetic acid (99mTc-DTPA), a low-molecular-mass hydrophilic tracer that is thought to cross the epithelium via paracellular pathways, and on blood flow.

The effects of indomethacin and thiorphan on bradykinin-induced albumin output and submucosal gland secretion in the ferret trachea in vivo.

In the ferret liquid-filled trachea in vivo, intraluminal bradykinin (BK, 3-300 microM) produced concentration-dependent increases in the output of lysozyme from submucosal gland serous cells and albumin movement into the lumen. Baseline outputs of albumin and lysozyme were not altered significantly by intraluminal indomethacin (10 microM) or thiorphan (10 microM). However, intraluminal indomethacin completely blocked the BK-induced increase in albumin output.

An in vivo preparation for measurement of plasma protein and lysozyme output in the ferret tracheal lumen.

An in-vivo ferret tracheal preparation has been developed to study the appearance in the liquid-filled trachea of fluorescein-labelled plasma proteins (FLP) and of lysozyme from submucosal gland serous cells. In order to investigate the influence of nervous activity on the appearance of FLP and lysozyme in the tracheal lumen, the effects of intraluminal bradykinin (an inflammatory mediator and sensory nerve stimulant), intraluminal capsaicin (a stimulant of C-fibres) and electrical stimulation of the cut peripheral end of the right cervical vagus nerve have been measured. Vagal stimulation (10 V, 10 Hz, 1 ms, 90-120 s) increased the secretory rate of lysozyme.

The effects of intraluminal and extraluminal drug application on secretion and smooth muscle tone in the ferret liquid-filled trachea in vitro.

With the ferret liquid-filled trachea in vitro, intraluminal methacholine (MCh), phenylephrine (PE) and histamine (Hist) increased smooth muscle tone and salbutamol (Salb) decreased tone. Lysozyme output was increased by intraluminal MCh and PE. Albumin transport into the lumen was not altered by intraluminal Hist, Salb or PE.

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.

Lateral nasal gland secretion in the anaesthetized dog.

The effects of pharmacological and nervous stimuli on the flow of secretion from the dog lateral nasal gland following catheterization are described. Drugs were injected close-arterially into the arterial supply to the nose, or intravenously. Cholinergic agonists (pilocarpine, methacholine), given intravenously (I.

Control of mucoglycoprotein output from the rabbit nose.

A method for the collection of rabbit nasal washings to analyse outputs of mucous glycoproteins is described. The radiolabels sodium [35S]sulphate and [3H]glucose are bound to the glycoproteins. The release of bound 35S and 3H was enhanced by cervical sympathetic nerve stimulation.