Exposure of immature rats to hyperoxia increases tracheal smooth muscle stress generation in vitro

1994 ◽  
Vol 76 (2) ◽  
pp. 743-749 ◽  
Author(s):  
M. B. Hershenson ◽  
M. E. Wylam ◽  
N. Punjabi ◽  
J. G. Umans ◽  
P. T. Schumacker ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Contractile Function ◽  
Stress Generation ◽  
Tracheal Smooth Muscle ◽  
Smooth Muscle Contractility ◽  
Cross Sectional ◽  
Induced Stress ◽  
Hyperoxic Exposure

Recently, we demonstrated that chronic exposure to hyperoxia causes in vivo airway muscarinic receptor hyperresponsiveness in the developing rat [Am. J. Physiol. 262 (Lung Cell. Mol. Physiol. 6): L263-L269, 1992]. To test whether airway cholinergic hyperresponsiveness might result from intrinsic alterations in smooth muscle contractility, we measured the effect of in vivo hyperoxia on the contractile force elicited by acetylcholine (ACh) of isometrically mounted tracheal rings in vitro. Tracheal rings were obtained from 3-wk-old rats exposed to air or to > 95% O2 for 8 days. Muscarinic responses were determined by measuring the force elicited by exposure to increasing concentrations of ACh. Responses were normalized to the morphometrically determined tracheal smooth muscle cross-sectional area in a plane perpendicular to the axis of force generation. In vivo O2 exposure significantly increased maximal ACh-induced stress generation (response to 10(-3) M ACh: air, 15.92 +/- 1.37 g/mm2; O2, 21.78 +/- 1.52 g/mm2; P = 0.010). The ACh-induced stress generation of cylinders from hyperoxic rats was substantially reduced by both epithelial removal and treatment with the cyclooxygenase inhibitor indomethacin. We conclude that in vivo hyperoxic exposure increases tracheal smooth muscle contractile function in vitro and that epithelium-derived prostaglandin(s) contributes to the observed increase in maximal contractile responsiveness.

scholarly journals Aging-associated changes in microRNA expression profile of internal anal sphincter smooth muscle: Role of microRNA-133a

2016 ◽  
Vol 311 (5) ◽  
pp. G964-G973 ◽  
Author(s):  
Jagmohan Singh ◽  
Ettickan Boopathi ◽  
Sankar Addya ◽  
Benjamin Phillips ◽  
Isidore Rigoutsos ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Anal Sphincter ◽  
Internal Anal Sphincter ◽  
Smooth Muscles ◽  
Smooth Muscle Contractility ◽  
Network Analyses ◽  
Rhoa Signaling

A comprehensive genomic and proteomic, computational, and physiological approach was employed to examine the (previously unexplored) role of microRNAs (miRNAs) as regulators of internal anal sphincter (IAS) smooth muscle contractile phenotype and basal tone. miRNA profiling, genome-wide expression, validation, and network analyses were employed to assess changes in mRNA and miRNA expression in IAS smooth muscles from young vs. aging rats. Multiple miRNAs, including rno-miR-1, rno-miR-340-5p, rno-miR-185, rno-miR-199a-3p, rno-miR-200c, rno-miR-200b, rno-miR-31, rno-miR-133a, and rno-miR-206, were found to be upregulated in aging IAS. qPCR confirmed the upregulated expression of these miRNAs and downregulation of multiple, predicted targets ( Eln, Col3a1, Col1a1, Zeb2, Myocd, Srf, Smad1, Smad2, Rhoa/Rock2, Fn1, Tagln v2, Klf4, and Acta2) involved in regulation of smooth muscle contractility. Subsequent studies demonstrated an aging-associated increase in the expression of miR-133a, corresponding decreases in RhoA, ROCK2, MYOCD, SRF, and SM22α protein expression, RhoA-signaling, and a decrease in basal and agonist [U-46619 (thromboxane A2analog)]-induced increase in the IAS tone. Moreover, in vitro transfection of miR-133a caused a dose-dependent increase of IAS tone in strips, which was reversed by anti-miR-133a. Last, in vivo perianal injection of anti-miR-133a reversed the loss of IAS tone associated with age. This work establishes the important regulatory effect of miRNA-133a on basal and agonist-stimulated IAS tone. Moreover, reversal of age-associated loss of tone via anti-miR delivery strongly implicates miR dysregulation as a causal factor in the aging-associated decrease in IAS tone and suggests that miR-133a is a feasible therapeutic target in aging-associated rectoanal incontinence.

Mechanical properties of human bronchial smooth muscle in vitro

1992 ◽  
Vol 73 (4) ◽  
pp. 1481-1485 ◽  
Author(s):  
K. Ishida ◽  
P. D. Pare ◽  
J. Hards ◽  
R. R. Schellenberg
Keyword(s):  
Mechanical Properties ◽  
Smooth Muscle ◽  
Electrical Field Stimulation ◽  
Tracheal Smooth Muscle ◽  
Cross Sectional ◽  
Velocity Of Shortening ◽  
Muscle Shortening ◽  
Tension Generation ◽  
Very High

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.

Phosphorylation of caldesmon by ERK MAP kinases in smooth muscle

2000 ◽  
Vol 278 (4) ◽  
pp. C718-C726 ◽  
Author(s):  
Jason C. Hedges ◽  
Brian C. Oxhorn ◽  
Michael Carty ◽  
Leonard P. Adam ◽  
Ilia A. Yamboliev ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Map Kinase ◽  
Map Kinases ◽  
Isometric Force ◽  
Phosphorylation Site ◽  
Smooth Muscle Contraction ◽  
Tracheal Smooth Muscle ◽  
Muscarinic Agonists

Phosphorylation of h-caldesmon has been proposed to regulate airway smooth muscle contraction. Both extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein (MAP) kinases phosphorylate h-caldesmon in vitro. To determine whether both enzymes phosphorylate caldesmon in vivo, phosphorylation-site-selective antibodies were used to assay phosphorylation of MAP kinase consensus sites. Stimulation of cultured tracheal smooth muscle cells with ACh or platelet-derived growth factor increased caldesmon phosphorylation at Ser789 by about twofold. Inhibiting ERK MAP kinase activation with 50 μM PD-98059 blocked agonist-induced caldesmon phosphorylation completely. Inhibiting p38 MAP kinases with 25 μM SB-203580 had no effect on ACh-induced caldesmon phosphorylation. Carbachol stimulation increased caldesmon phosphorylation at Ser789 in intact tracheal smooth muscle, which was blocked by the M2 antagonist AF-DX 116 (1 μM). AF-DX 116 inhibited carbachol-induced isometric contraction by 15 ± 1.4%, thus dissociating caldesmon phosphorylation from contraction. Activation of M2 receptors leads to activation of ERK MAP kinases and phosphorylation of caldesmon with little or no functional effect on isometric force. P38 MAP kinases are also activated by muscarinic agonists, but they do not phosphorylate caldesmon in vivo.

scholarly journals Decreased airway narrowing and smooth muscle contraction in hyperresponsive pigs

2002 ◽  
Vol 93 (4) ◽  
pp. 1296-1300 ◽  
Author(s):  
Debra J. Turner ◽  
Peter B. Noble ◽  
Matthew P. Lucas ◽  
Howard W. Mitchell
Keyword(s):  
Smooth Muscle ◽  
Airway Hyperresponsiveness ◽  
Porcine Model ◽  
Smooth Muscle Contraction ◽  
Airway Wall ◽  
Muscle Contractility ◽  
Smooth Muscle Contractility ◽  
Airway Narrowing

Increased smooth muscle contractility or reduced smooth muscle mechanical loads could account for the excessive airway narrowing and hyperresponsiveness seen in asthma. These mechanisms were investigated by using an allergen-induced porcine model of airway hyperresponsiveness. Airway narrowing to electric field stimulation was measured in isolated bronchial segments, over a range of transmural pressures (0–20 cmH2O). Contractile responses to ACh were measured in bronchial segments and in isolated tracheal smooth muscle strips isolated from control and test (ovalbumin sensitized and challenged) pigs. Test airways narrowed less than controls ( P < 0.0001). Test pigs showed reduced contractility to ACh, both in isolated bronchi ( P < 0.01) and smooth muscle strips ( P < 0.01). Thus isolated airways from pigs exhibiting airway hyperresponsiveness in vivo are hyporesponsive in vitro. The decreased narrowing in bronchi from hyperresponsive pigs may be related to decreased smooth muscle contractility. These data suggest that mechanisms external to the airway wall may be important to the hyperresponsive nature of sensitized lungs.

Release of epithelium-derived PGE2 from canine trachea after antigen inhalation

1998 ◽  
Vol 274 (2) ◽  
pp. L220-L225 ◽  
Author(s):  
I. McGrogan ◽  
L. J. Janssen ◽  
J. Wattie ◽  
P. M. O’Byrne ◽  
E. E. Daniel
Keyword(s):  
Smooth Muscle ◽  
Electrical Field Stimulation ◽  
Tracheal Smooth Muscle ◽  
Organ Bath ◽  
Field Stimulation ◽  
Electrical Field ◽  
Concentration Response Curve

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.

Interleukin-1β-induced airway hyperresponsiveness enhances substance P in intrinsic neurons of ferret airway

2002 ◽  
Vol 283 (5) ◽  
pp. L909-L917 ◽  
Author(s):  
Z.-X. Wu ◽  
B. E. Satterfield ◽  
J. S. Fedan ◽  
R. D. Dey
Keyword(s):  
Smooth Muscle ◽  
Substance P ◽  
Airway Smooth Muscle ◽  
Airway Hyperresponsiveness ◽  
Sensory Nerves ◽  
Tracheal Smooth Muscle ◽  
Fiber Density ◽  
Smooth Muscle Contractility ◽  
Neurokinin 1

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.

Relationship between in vivo Airway Reactivity and in vitro Responsiveness of Tracheal Smooth Muscle in Inbred Rats

Respiration ◽  
1988 ◽  
Vol 54 (1) ◽  
pp. 108-113 ◽  
Author(s):  
G.U. Di Maria ◽  
J.G. Martin ◽  
S. Bellofiore ◽  
A. Mistretta
Keyword(s):  
Smooth Muscle ◽  
Tracheal Smooth Muscle ◽  
Airway Reactivity ◽  
Inbred Rats

scholarly journals VIP/PACAP Signaling as an Alternative Target During Hyperoxic Exposure in Preterm Newborns

2021 ◽  
pp. 489-499
Author(s):  
Qëndrim Thaçi ◽  
Shkëlzen Reçica ◽  
Islam Kryeziu ◽  
Vadim Mitrokhin ◽  
Andre Kamkin ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Adenylate Cyclase ◽  
Airway Smooth Muscle ◽  
Smooth Muscle Relaxation ◽  
Smooth Muscle Contractility ◽  
Hyperoxic Exposure ◽  
Airway Caliber ◽  
Pituitary Adenylate Cyclase ◽  
Preterm Newborns

The use of oxygen therapy (high doses of oxygen - hyperoxia) in the treatment of premature infants results in their survival. However, it also results in a high incidence of chronic lung disease known as bronchopulmonary dysplasia, a disease in which airway hyper-responsiveness and pulmonary hypertension are well known as consequences. In our previous studies, we have shown that hyperoxia causes airway hyper-reactivity, characterized by an increased constrictive and impaired airway smooth muscle relaxation due to a reduced release of relaxant molecules such as nitric oxide, measured under in vivo and in vitro conditions (extra- and intrapulmonary) airways. In addition, the relaxation pathway of the vasoactive intestinal peptide (VIP) and/or pituitary adenylate cyclase activating peptide (PACAP) is another part of this system that plays an important role in the airway caliber. Peptide, which activates VIP cyclase and pituitary adenylate cyclase, has prolonged airway smooth muscle activity. It has long been known that VIP inhibits airway smooth muscle cell proliferation in a mouse model of asthma, but there is no data about its role in the regulation of airway and tracheal smooth muscle contractility during hyperoxic exposure of preterm newborns.

Expression of airway contractile properties and acetylcholinesterase activity in swine

1989 ◽  
Vol 67 (1) ◽  
pp. 174-180 ◽  
Author(s):  
T. M. Murphy ◽  
R. W. Mitchell ◽  
J. S. Blake ◽  
M. M. Mack ◽  
E. A. Kelly ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Acetylcholinesterase Activity ◽  
Contractile Properties ◽  
Tracheal Smooth Muscle ◽  
Cholinesterase Inhibition ◽  
Maximal Response ◽  
Response Curves ◽  
Cross Sectional

We studied the effect of maturation on contractile properties of tracheal smooth muscle from seventeen 2-wk-old swine (2ws) and fifteen 10-wk-old swine (10ws) in situ and in vitro. The response to parasympathetic stimulation was studied in situ in isometrically fixed segments. Contraction was elicited at lower frequencies [half-maximal response to electrical stimulation (ES50) = 6.7 +/- 0.05 Hz] in 2ws than in 10ws (ES50 = 9.1 +/- 0.4 Hz; P less than 0.01). Despite substantial differences in morphometrically normalized cross-sectional area in 2ws (0.012 +/- 0.003 cm2) and 10ws (0.028 +/- 0.001 cm2; P less than 0.01), maximal active tension elicited by parasympathetic stimulation was similar (12.4 +/- 3.2 g/cm in 2ws vs. 13.3 +/- 2.3 g/cm in 10ws; P = NS). In separate in vitro studies in 25 tracheal smooth muscle strips from 10 swine, concentration-response curves generated with potassium-substituted Krebs solution (KCl) were similar in 2ws and 10ws. In 58 other strips (10 swine), maximal active force elicited with acetylcholine (ACh) in 2ws was significantly greater than for 10ws (P less than 0.001). Removal of the epithelium had no effect. However, cholinesterase inhibition with 10(-7) M physostigmine augmented the response to ACh in 10ws (P less than 0.02) but not 2ws. We demonstrate increased force generation and sensitivity to vagal stimulation in 2ws vs. 10ws, which corresponds to increased reactivity to ACh in vitro. The relative hyperresponsiveness in 2ws is specific for cholinergic response and is attenuated at least in part by maturation of the activity of acetylcholinesterase enzyme.

Activation of alpha-adrenergic response in tracheal smooth muscle: a postreceptor mechanism

1983 ◽  
Vol 54 (6) ◽  
pp. 1469-1476 ◽  
Author(s):  
P. J. Barnes ◽  
B. E. Skoogh ◽  
J. K. Brown ◽  
J. A. Nadel
Keyword(s):  
Smooth Muscle ◽  
Contractile Response ◽  
Electrical Field Stimulation ◽  
Tracheal Smooth Muscle ◽  
Adrenergic Blockade ◽  
Adrenergic Response ◽  
Receptor Number ◽  
Related Process

We have investigated the activation of alpha-adrenergic contractile responses in dog tracheal smooth muscle. After cholinergic and beta-adrenergic blockade, neither electrical field stimulation nor alpha-adrenergic agonists caused contraction of trachealis strips in vitro, but after exposure to histamine or serotonin a striking contractile response was obtained. Similar activation of the contractile response to norepinephrine was seen in isolated tracheal segments in vivo after exposure to histamine and serotonin. This response was mediated predominantly by alpha 2-adrenoceptors, because the alpha 2-antagonist yohimbine was a potent inhibitor whereas the alpha 1-antagonist prazosin was a weak inhibitor of the response to both electrical stimulation and exogenous agonists. Using [3H]yohimbine to label alpha 2-receptors and [3H]prazosin to label alpha 1-receptors, we confirmed the preponderance of alpha 2-receptors in trachealis membranes but found no increase in either receptor number or affinity after incubating muscle strips with histamine. The magnitude of alpha-adrenergic contraction was significantly related to the magnitude of precontraction by histamine and serotonin both in vitro and in vivo but persisted after washout. Acetylcholine was much less potent in activating the alpha-adrenergic response. We conclude that activation of airway alpha-adrenergic responses involves a postreceptor mechanism not directly related to membrane depolarization, but involving some related process such as activation of calcium channels.

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