scholarly journals Substance P Regulates Environmental Tobacco Smoke-Enhanced Tracheal Smooth Muscle Responsiveness in Mice

2012 ◽  
Vol 2012 ◽  
pp. 1-10
Author(s):  
Lan Xiao ◽  
Zhong-Xin Wu

Environmental tobacco smoke (ETS) is an environmental trigger that leads to airway inflammation and airway hyperresponsiveness (AHR) in susceptible individuals and animals, but the underlying mechanism is not fully understood. Substance P (SP) release from sensory nerve fibers has been linked to AHR. The present experiments characterize the role of SP in tracheal smooth muscle on ETS-increased airway responses. The mice were exposed to either sidestream tobacco smoke (SS), a surrogate to ETS, or filtered air (FA) for 1 day or 5 consecutive days. Contractions of tracheal smooth muscle to SP and electrical field stimulation (EFS) were not significantly altered in 1 of day SS-exposed mice. However, 5 of days SS exposure significantly increased airway smooth muscle contractions to SP and EFS. Administration of CP-99994, an antagonist of the neurokinin (NK)1 receptor, attenuates the SS exposure-enhanced tracheal smooth muscle responses to EFS. Furthermore, the immunohistochemistry showed that SP nerve fibers were increased in tracheal smooth muscle after 5 of days SS exposure. These results suggest that the increased SP production may contribute to SS-enhanced smooth muscle responsiveness in mice trachea.

2012 ◽  
Vol 302 (1) ◽  
pp. L152-L159 ◽  
Author(s):  
Z.-X. Wu ◽  
K. B. Benders ◽  
D. D. Hunter ◽  
R. D. Dey

Our recent study showed that prenatal and early postnatal exposure of mice to side-steam tobacco smoke (SS), a surrogate to environmental tobacco smoke (ETS), leads to increased airway responsiveness and sensory innervation later in life. However, the underlying mechanism initiated in early life that affects airway responses later in life remains undefined. The concomitant increase in nerve growth factor (NGF) after exposures suggests that NGF may be involved the regulation of airway innervation. Since NGF regulates sympathetic nerve responses, as well as sensory nerves, we extended previous studies by examining neuropeptide Y (NPY), a neuropeptide associated with sympathetic nerves. Different age groups of mice, postnatal day (PD) 2 and PD21, were exposed to either SS or filtered air (FA) for 10 consecutive days. The level of NPY protein in lung and the density of NPY nerve fibers in tracheal smooth muscle were significantly increased in the PD2–11SS exposure group compared with PD2–11FA exposure. At the same time, the level of NGF in lung tissue was significantly elevated in the PD2–11SS exposure groups. However, neither NPY (protein or nerves) nor NGF levels were significantly altered in PD21–30SS exposure group compared with the PD21–30FA exposure group. Furthermore, pretreatment with NGF antibody or K252a, which inhibits a key enzyme (tyrosine kinase) in the transduction pathway for NGF receptor binding, significantly diminished SS-enhanced NPY tracheal smooth muscle innervation and the increase in methacholine-induced airway resistance. These findings show that SS exposure in early life increases NPY tracheal innervation and alters pulmonary function and that these changes are mediated through the NGF.


2001 ◽  
Vol 91 (1) ◽  
pp. 371-378 ◽  
Author(s):  
Zhong-Xin Wu ◽  
David F. Maize ◽  
Brian E. Satterfield ◽  
David G. Frazer ◽  
Jeff S. Fedan ◽  
...  

Exposure to ozone (O3) enhances airway responsiveness, which is mediated partly by the release of substance P (SP) from airway neurons. In this study, the role of intrinsic airway neurons in O3-induced airway responses was examined. Ferrets were exposed to 2 ppm O3 or air for 1 h. Reactivity of isolated tracheal smooth muscle to cholinergic agonists was significantly increased after O3 exposure, as were contractions to electrical field stimulation at 10 Hz. Pretreatment with CP-99994, a neurokinin type 1 receptor antagonist, partially abolished the O3-induced reactivity to cholinergic agonists and electrical field stimulation. The O3-enhanced airway responses were present in tracheal segments cultured for 24 h, a procedure shown to deplete sensory nerves while maintaining viability of intrinsic airway neurons, and all the enhanced smooth muscle responses were also diminished by CP-99994. Immunocytochemistry showed that the percentage of SP-containing neurons in longitudinal trunk and the percentage of neurons innervated by SP-positive nerve fibers in superficial muscular plexus were significantly increased at 1 h after exposure to O3. These results suggest that enhanced SP levels in airway ganglia contribute to O3-induced airway hyperresponsiveness.


2003 ◽  
Vol 95 (2) ◽  
pp. 742-750 ◽  
Author(s):  
Zhong-Xin Wu ◽  
Brian E. Satterfield ◽  
Richard D. Dey

Exposure to ozone (O3) induces airway hyperresponsiveness mediated partly through the release of substance P (SP) from nerve terminals in the airway wall. Although substantial evidence suggests that SP is released by sensory nerves, SP is also present in neurons of airway ganglia. The purpose of this study was to investigate the role of intrinsic airway neurons in O3-enhanced airway responsiveness in ferret trachea. To remove the effects of sensory innervation, segments of ferret trachea were maintained in culture conditions for 24 h before in vitro exposure to 2 parts/million of O3 or air for 1 h. Sensory nerve depletion was confirmed by showing that capsaicin did not affect tracheal smooth muscle responsiveness to cholinergic agonist or contractility responses to electrical field stimulation (EFS). Contractions of isolated tracheal smooth muscle to EFS were significantly increased after in vitro O3 exposure, but the constrictor response to cholinergic agonist was not altered. Pretreatment with CP-99994, an antagonist of the neurokinin 1 receptor, attenuated the increased contraction to EFS after O3 exposure but had no effect in the air exposure group. The number of SP-positive neurons in longitudinal trunk ganglia, the extent of SP innervation to superficial muscular plexus nerve cell bodies, and SP nerve fiber density in tracheal smooth muscle all increased significantly after O3 exposure. The results show that release of SP from intrinsic airway neurons contributes to O3-enhanced tracheal smooth muscle responsiveness by facilitating acetylcholine release from cholinergic nerve terminals.


1992 ◽  
Vol 73 (4) ◽  
pp. 1481-1485 ◽  
Author(s):  
K. Ishida ◽  
P. D. Pare ◽  
J. Hards ◽  
R. R. Schellenberg

The in vitro mechanical properties of smooth muscle strips from 10 human main stem bronchi obtained immediately after pneumonectomy were evaluated. Maximal active isometric and isotonic responses were obtained at varying lengths by use of electrical field stimulation (EFS). At the length (Lmax) producing maximal force (Pmax), resting tension was very high (60.0 +/- 8.8% Pmax). Maximal fractional muscle shortening was 25.0 +/- 9.0% at a length of 75% Lmax, whereas less shortening occurred at Lmax (12.2 +/- 2.7%). The addition of increasing elastic loads produced an exponential decrease in the shortening and velocity of shortening but increased tension generation of muscle strips stimulated by EFS. Morphometric analysis revealed that muscle accounted for 8.7 +/- 1.5% of the total cross-sectional tissue area. Evaluation of two human tracheal smooth muscle preparations revealed mechanics similar to the bronchial preparations. Passive tension at Lmax was 10-fold greater and maximal active shortening was threefold less than that previously demonstrated for porcine trachealis by us of the same apparatus. We attribute the limited shortening of human bronchial and tracheal smooth muscle to the larger load presumably provided by a connective tissue parallel elastic component within the evaluated tissues, which must be overcome for shortening to occur. We suggest that a decrease in airway wall elastance could increase smooth muscle shortening, leading to excessive responses to contractile agonists, as seen in airway hyperresponsiveness.


2000 ◽  
Vol 279 (2) ◽  
pp. L350-L359 ◽  
Author(s):  
Gary L. Larsen ◽  
Carl W. White ◽  
Katsuyuki Takeda ◽  
Joan E. Loader ◽  
Dee Dee H. Nguyen ◽  
...  

Within the respiratory epithelium of asthmatic patients, copper/zinc-containing superoxide dismutase (Cu/Zn SOD) is decreased. To address the hypothesis that lung Cu/Zn SOD protects against allergen-induced injury, wild-type and transgenic mice that overexpress human Cu/Zn SOD were either passively sensitized to ovalbumin (OVA) or actively sensitized by repeated airway exposure to OVA. Controls included nonsensitized wild-type and transgenic mice given intravenous saline or airway exposure to saline. After aerosol challenge to saline or OVA, segments of tracheal smooth muscle were obtained for in vitro analysis of neural control. In response to electrical field stimulation, wild-type sensitized mice challenged with OVA had significant increases in cholinergic reactivity. Conversely, sensitized transgenic mice challenged with OVA were resistant to changes in neural control. Stimulation of tracheal smooth muscle to elicit acetylcholine release showed that passively sensitized wild-type but not transgenic mice released more acetylcholine after OVA challenge. Function of the M2 muscarinic autoreceptor was preserved in transgenic mice. These results demonstrate that murine airways with elevated Cu/Zn SOD were resistant to allergen-induced changes in neural control.


1998 ◽  
Vol 274 (2) ◽  
pp. L220-L225 ◽  
Author(s):  
I. McGrogan ◽  
L. J. Janssen ◽  
J. Wattie ◽  
P. M. O’Byrne ◽  
E. E. Daniel

To investigate the role of prostaglandin (PG) E2 in allergen-induced hyperresponsiveness, dogs inhaled either the allergen Ascaris suum or vehicle (Sham). Twenty-four hours after inhalation, some animals exposed to allergen demonstrated an increased responsiveness to acetylcholine challenge in vivo (Hyp-Resp), whereas others did not (Non-Resp). Strips of tracheal smooth muscle, either epithelium intact or epithelium denuded, were suspended on stimulating electrodes, and a concentration-response curve to carbachol (10−9 to 10−5 M) was generated. Tissues received electrical field stimulation, and organ bath fluid was collected to determine PGE2content. With the epithelium present, all three groups contracted similarly to 10−5 M carbachol, whereas epithelium-denuded tissues from animals that inhaled allergen contracted more than tissues from Sham dogs. In response to electrical field stimulation, Hyp-Resp tissues contracted less than Sham tissues in the presence of epithelium and more than Sham tissues in the absence of epithelium. PGE2release in the muscle bath was greater in Non-Resp tissues than in Sham or Hyp-Resp tissues when the epithelium was present. Removal of the epithelium greatly inhibited PGE2release. We conclude that tracheal smooth muscle is hyperresponsive in vitro after in vivo allergen exposure only when the modulatory effect of the epithelium, largely through PGE2 release, is removed.


1984 ◽  
Vol 57 (1) ◽  
pp. 129-134 ◽  
Author(s):  
E. H. Walters ◽  
P. M. O'Byrne ◽  
L. M. Fabbri ◽  
P. D. Graf ◽  
M. J. Holtzman ◽  
...  

Contractile responses of canine tracheal smooth muscle to electrical field stimulation diminished over a 2-h period of incubation. However, addition of indomethacin (10(-5) M) for a similar time not only prevented this inhibition of contractile response, but actually markedly increased the response to electrical field stimulation, suggesting that prostaglandins were responsible for the time-dependent inhibition. Measured prostaglandin E2 increased in the tissue bath over 2 h in control tissues. Addition of prostaglandin E2 to the tissue produced similar inhibition of contractile responses to electrical field stimulation in a concentration-dependent manner. In contrast, incubation alone, treatment with indomethacin, or addition of prostaglandin E2 had little, if any, effect on contractions induced by acetylcholine. We conclude that the release of prostaglandins from canine tracheal smooth muscle that occurs with time has a predominantly inhibitory effect on cholinergic neurotransmission at a prejunctional site.


1992 ◽  
Vol 262 (4) ◽  
pp. L511-L514 ◽  
Author(s):  
M. S. Kannan ◽  
D. E. Johnson

In pig tracheal smooth muscle, the isometric tension responses to electrical field stimulation (EFS) were studied after raising the tone with carbamylcholine chloride (carbachol). EFS induced frequency-dependent relaxations that were nonadrenergic, noncholinergic (NANC) in nature. Addition of NG-nitro-L-arginine (L-NOArg), an inhibitor of nitric oxide (NO) synthesis from L-arginine, resulted in concentration-dependent inhibition of the relaxation response to EFS. Pretreatment of the tissues with L-arginine (1 mM) prevented the inhibitory effect of L-NOArg on the EFS-induced relaxations at the frequencies studied. However, in the presence of D-arginine, EFS-induced relaxations were inhibited by L-NOArg. L-Arginine, D-arginine, and L-NOArg had no significant effects on basal tone of the muscle. In the presence of L-NOArg, vasoactive intestinal polypeptide (3 x 10(-7) M), the nicotinic agonist dimethylphenyl piperazinium bromide (100 microM), and isoproterenol (1 microM) relaxed carbachol-induced tone. The concentration-dependent selective inhibition of neural relaxation by L-NOArg and its reversal by L-arginine in a stereospecific manner are consistent with NO-mediated NANC relaxation of pig tracheal smooth muscle.


2002 ◽  
Vol 283 (5) ◽  
pp. L909-L917 ◽  
Author(s):  
Z.-X. Wu ◽  
B. E. Satterfield ◽  
J. S. Fedan ◽  
R. D. Dey

Interleukin (IL)-1β causes airway inflammation, enhances airway smooth muscle responsiveness, and alters neurotransmitter expression in sensory, sympathetic, and myenteric neurons. This study examines the role of intrinsic airway neurons in airway hyperresponsiveness (AHR) induced by IL-1β. Ferrets were instilled intratracheally with IL-1β (0.3 μg/0.3 ml) or saline (0.3 ml) once daily for 5 days. Tracheal smooth muscle contractility in vitro and substance P (SP) expression in tracheal neurons were assessed. Tracheal smooth muscle reactivity to acetylcholine (ACh) and methacholine (MCh) and smooth muscle contractions to electric field stimulation (EFS) both increased after IL-1β. The IL-1β-induced AHR was maintained in tracheal segments cultured for 24 h, a procedure that depletes SP from sensory nerves while maintaining viability of intrinsic airway neurons. Pretreatment with CP-99994, an antagonist of neurokinin 1 receptor, attenuated the IL-1β-induced hyperreactivity to ACh and MCh and to EFS in cultured tracheal segments. SP-containing neurons in longitudinal trunk, SP innervation of superficial muscular plexus neurons, and SP nerve fiber density in tracheal smooth muscle all increased after treatment with IL-1β. These results show that IL-1β-enhanced cholinergic airway smooth muscle contractile responses are mediated by the actions of SP released from intrinsic airway neurons.


1980 ◽  
Vol 238 (1) ◽  
pp. C27-C33 ◽  
Author(s):  
M. S. Kannan ◽  
E. E. Daniel

The structural bases for myogenic and neurogenic control of canine tracheal smooth muscle were studied. At optimum lengths, strips of muscle showed insignificant neurogenic or myogenic tone. Atropine and/or tetrodotoxin blocked the contractile responses elicited on electrical field stimulation of intrinsic nerves. After raising the tone with tetraethylammonium ion and in the presence of atropine, field stimulation of nerves caused a relaxation, a major component of which was blocked by propranolol and/or tetrodotoxin, suggesting an effect mediated through interaction of mediator released from sympathetic nerves with beta-adrenergic receptors. Electron microscopic studies revealed gap junctions between extensions of smooth-muscle cells and a sparse innervation. The axonal varicosities, corresponding to cholinergic (predominantly) and adrenergic (occasionally) nerves, were seen predominantly in the clefts between cell bundles. The physiological responses were compared with the morphological features. Although this muscle exhibits multiunit behavior in vitro, implying that nerves initiate the coordinate activity, its ultrastructural features suggest a potential for single-unit behavior.


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