Effect of Bovine Surfactant on Mucus Secretion from Tracheal Submucosal Glands

To model the airway glandular defect in cystic fibrosis (CF), the effect of anion secretion blockers on submucosal gland mucus secretion was investigated. Porcine distal bronchi were isolated, pretreated with a Cl- secretion blocker (bumetanide) and/or a combination of blockers to inhibit HCO3- secretion (dimethylamiloride, acetazolamide, and 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid), and then treated with acetylcholine (ACh), a glandular liquid and mucus secretagogue. Bronchi were then fixed, sectioned, and stained for mucins. Each gland duct was ranked for mucin content from zero (no mucin) to five (duct completely occluded with mucin). Untreated bronchi, bronchi treated only with ACh, and ACh-treated bronchi that received either bumetanide or the HCO3- secretion blockers all exhibited low gland duct mucin content (1.18 +/- 0.34, 0.59 +/- 0.07, 0.65 +/- 0.03, and 0.83 +/- 0.11, respectively). However, pretreatment with both Cl- and HCO3- secretion blockers before ACh addition resulted in substantial and significant ductal mucus accumulation (3.57 +/- 0.22). In situ videomicroscopy studies of intact airways confirmed these results. Thus inhibition of the anion (and presumably liquid) secretion response to ACh leads to mucus obstruction of submucosal gland ducts that resembles the early pathological changes observed in CF.

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Muscarinic stimulation of submucosal glands in swine trachea

Journal of Applied Physiology ◽

10.1152/jappl.1988.64.1.200 ◽

1988 ◽

Vol 64 (1) ◽

pp. 200-209 ◽

Cited By ~ 19

Author(s):

C. M. Yang ◽

J. M. Farley ◽

T. M. Dwyer

Keyword(s):

Acetylcholine Receptors ◽

Relative Proportion ◽

Muscarinic Acetylcholine Receptors ◽

Mucus Secretion ◽

Submucosal Gland ◽

Isolated Cells ◽

Gland Cells ◽

Submucosal Glands ◽

Tracheal Explants

The properties of muscarinic acetylcholine receptors (mAChR) on tracheal explants and isolated submucosal gland cells were determined using [3H]quinuclidinyl benzilate ([3H]QNB) and N-[3H]methylscopolamine ([3H]NMS) as ligands. Analysis of competitive displacement of ([3H]NMS binding by pirenzepine demonstrated the presence of M1- (27 +/- 2%) and M2G- (73 +/- 2%) receptors on isolated tracheal submucosal gland cells (TSGC's) in control. Daily administration of diisopropylfluorophosphate (DFP) inhibited cholinesterase activity by greater than 95%. After 7 days of DFP treatment, [3H]QNB binding to intact TSGC's decreased from 14.2 +/- 0.6 to 6.3 +/- 0.8 fmol/10(6) cells; similarly, [3H]NMS binding fell from 8.1 +/- 1.9 to 2.0 +/- 0.8 fmol/10(6) cells. The loss of mAChR's was predominantly of the M2G subtype with the relative proportion dropping to 33%. In addition, 90% of the receptors assumed the high-affinity state for carbachol displacement of [3H]NMS. Mucus secretion was quantitated by measuring the release of 3H-labeled mucus macromolecules from explants of tracheal submucosal glands and isolated cells. Acetylcholine (ACh), 2 X 10(-5) M, stimulated mucus secretion by 2.5 and 2.3 times the basal rate, respectively. Elimination of acetylcholinesterase (AChe) by DFP increased the ACh sensitivity by 18- and 5-fold. Tracheal explants or TSGC's obtained 2 h after an in vivo DFP treatment showed a 6- and 3-fold ACh stimulation. This ACh sensitivity decreased during the continued daily dosing with DFP such that only a 1.3- and 1.1-fold ACh stimulation was apparent after 7 days of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

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Effect of epithelium on mucus secretion from feline tracheal submucosal glands

Journal of Applied Physiology ◽

10.1152/jappl.1989.66.2.764 ◽

1989 ◽

Vol 66 (2) ◽

pp. 764-770 ◽

Cited By ~ 17

Author(s):

T. Sasaki ◽

S. Shimura ◽

H. Sasaki ◽

T. Takishima

Keyword(s):

Airway Epithelium ◽

Inhibitory Action ◽

Mucus Secretion ◽

Submucosal Gland ◽

Leukotriene D4 ◽

Lipoxygenase Inhibitors ◽

Beta Adrenergic Agonists ◽

Submucosal Glands ◽

Acid Metabolites ◽

Mucosal Explants

We studied the effect of airway epithelium on mucus secretion by use of an isolated tracheal submucosal gland preparation reported previously (J. Appl. Physiol. 60: 1237–1247, 1986). Mucus glycoconjugate release from submucosal glands of feline trachea was examined using [3H]glucosamine as a mucus precursor. Isolated glands showed significantly higher secretory responses to cholinergic, alpha-, and beta-adrenergic agonists and dibutyryladenosine 3′,5′-cyclic monophosphate (average 400% of control) than the conventional tracheal mucosal explants, which contained epithelium and submucosal tissues in addition to submucosal glands (average 160% of control). The addition of isolated epithelium depressed the secretory response of isolated glands to the same level as that of tracheal explants. However, the supernatant from isolated epithelium failed to inhibit secretory responses to methacholine in isolated glands, suggesting that the epithelium-derived inhibitory factor to secretion may be short-lived. Leukotriene D4 antagonist (FPL 55712), cyclooxygenase and/or lipoxygenase inhibitors (indomethacin or BW 755C) caused no significant change in the inhibitory action of epithelium, suggesting that the inhibition is not due to arachidonic acid metabolites. The newly found secretory inhibitory action of epithelium is of particular interest in the pathogenesis of hypersecretion associated with epithelial damage.

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Mucus secretion from individual submucosal glands of the ferret trachea

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00049.2010 ◽

2010 ◽

Vol 299 (1) ◽

pp. L124-L136 ◽

Cited By ~ 19

Author(s):

Hyung-Ju Cho ◽

Nam Soo Joo ◽

Jeffrey J. Wine

Keyword(s):

Optical Imaging ◽

Fluid Secretion ◽

Time Lapse ◽

Secretion Rate ◽

Mucus Secretion ◽

Muscle Synergy ◽

Parametric Data ◽

Submucosal Glands ◽

Trachealis Muscle ◽

Secretion Rates

Mucus secretion from individual tracheal glands in adult ferrets was studied with time-lapse optical imaging of mucus droplets under an oil layer. Density of functional glands (determined by responses to 1 μM carbachol) was 1.5 ± 0.3 per mm2 ( n = 6). Secretion rates (in pl·min−1·gland−1) were as follows: 4.1 ± 0.7 basal (unstimulated; n = 27, 669 glands), 338 ± 70 to 10 μM forskolin ( n = 8, 90 glands), 234 ± 13 to 1 μM VIP ( n = 6, 57 glands), 183 ± 92 to 10 μM isoproterenol ( n = 3, 33 glands), 978 ± 145 to 1 μM carbachol ( n = 11, 131 glands), and 1,348 ± 325 to 10 μM phenylephrine ( n = 7, 74 glands). The potency (EC50, in μM) and efficacy ( Vmax, in pl·min−1·gland−1) were 7.6 (EC50) and 338 ± 16 ( Vmax) to forskolin, 1.0 (EC50) and 479 ± 19 ( Vmax) to VIP, 0.6 (EC50) and 1,817 ± 268 ( Vmax) to carbachol, and 3.7 (EC50) and 1,801 ± 95 ( Vmax) to phenylephrine. Although carbachol and phenylephrine were equally effective secretagogues, only carbachol caused contractions of the trachealis muscle. Synergy was demonstrated between 300 nM isoproterenol and 100 nM carbachol, which, when combined, produced a secretion rate almost fourfold greater than predicted from their additive effect. The dependence of fluid secretion on Cl− and HCO3− varied depending on the mode of stimulation. Secretion stimulated by VIP or forskolin was reduced by ∼60% by blocking either anion, while carbachol-stimulated secretion was blocked 68% by bumetanide and only 32% by HEPES replacement of HCO3−. These results provide parametric data for comparison with fluid secretion from glands in ferrets lacking CFTR.

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Optical method for quantifying rates of mucus secretion from single submucosal glands

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.2001.281.2.l458 ◽

2001 ◽

Vol 281 (2) ◽

pp. L458-L468 ◽

Cited By ~ 56

Author(s):

Nam Soo Joo ◽

Jin V. Wu ◽

Mauri E. Krouse ◽

Yamil Saenz ◽

Jeffrey J. Wine

Keyword(s):

Optical Method ◽

Secretory Response ◽

Mucus Secretion ◽

Gland Secretion ◽

Transient Responses ◽

Tracheal Mucosa ◽

Submucosal Glands ◽

Spherical Bubbles ◽

Secretion Rates

We describe an optical method to quantify single- gland secretion. Isolated tracheal mucosa were mounted at the air-Krebs interface and coated with oil. Gland secretions formed spherical bubbles that were digitally imaged at intervals, allowing rates of secretion to be calculated. We monitored 340 glands in 54 experiments with 12 sheep. Glands secreted basally at low rates (0.57 ± 0.04 nl · min−1 · gland−1, 123 glands) in tissues up to 9 h postharvest and at lower rates for up to 3 days. Carbachol (10 μM) stimulated secretion with an early transient and a sustained or oscillating phase. Peak secretion was 15.7 ± 1.2 nl · min−1 · gland−1 (60 glands); sustained secretion was 4.5 ± 0.5 nl · min−1 · gland−1 (10 glands). Isoproterenol and phenylephrine (10 μM each) stimulated only small, transient responses. We confirmed that cats have a large secretory response to phenylephrine (11.6 ± 3.7 nl · min−1 · gland−1, 12 glands), but pigs, sheep, and humans all have small responses (<2 nl · min−1 · gland−1). Carbachol-stimulated peak secretion was inhibited 56% by bumetanide, 67% by HCO[Formula: see text] replacement with HEPES, and 92% by both. The distribution of secretion rates was nonnormal, suggesting the existence of subpopulations of glands.

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Acid exposure disrupts mucus secretion and impairs mucociliary transport in neonatal piglet airways

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00025.2020 ◽

2020 ◽

Vol 318 (5) ◽

pp. L873-L887 ◽

Cited By ~ 1

Author(s):

Yan Shin J. Liao ◽

Shin Ping Kuan ◽

Maria V. Guevara ◽

Emily N. Collins ◽

Kalina R. Atanasova ◽

...

Keyword(s):

Airway Obstruction ◽

Chloride Transport ◽

Ex Vivo ◽

Mucus Secretion ◽

Mucociliary Transport ◽

Cholinergic Stimulation ◽

Diminazene Aceturate ◽

Airway Pathology ◽

Submucosal Glands ◽

Airway Acidification

Tenacious mucus produced by tracheal and bronchial submucosal glands is a defining feature of several airway diseases, including cystic fibrosis (CF). Airway acidification as a driving force of CF airway pathology has been controversial. Here we tested the hypothesis that transient airway acidification produces pathologic mucus and impairs mucociliary transport. We studied pigs challenged with intra-airway acid. Acid had a minimal effect on mucus properties under basal conditions. However, cholinergic stimulation in acid-challenged pigs revealed retention of mucin 5B (MUC5B) in the submucosal glands, decreased concentrations of MUC5B in the lung lavage fluid, and airway obstruction. To more closely mimic a CF-like environment, we also examined mucus secretion and transport following cholinergic stimulation under diminished bicarbonate and chloride transport conditions ex vivo. Under these conditions, airways from acid-challenged pigs displayed extensive mucus films and decreased mucociliary transport. Pretreatment with diminazene aceturate, a small molecule with ability to inhibit acid detection through blockade of the acid-sensing ion channel (ASIC) at the doses provided, did not prevent acid-induced pathologic mucus or transport defects but did mitigate airway obstruction. These findings suggest that transient airway acidification early in life has significant impacts on mucus secretion and transport properties. Furthermore, they highlight diminazene aceturate as an agent that might be beneficial in alleviating airway obstruction.

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