Response Of Tracheal Muscle Research Articles

The effect of Nigella sativa alone, and in combination with dexamethasone, on tracheal muscle responsiveness and lung inflammation in sulfur mustard exposed guinea pigs

Ethnomedical relevance The anti-inflammatory activity of both systemic and local administrations of essential oil from Nigella sativa L. has been shown. Aim of the study Therefore, the effect of Nigella sativa on tracheal responsiveness (TR) and lung inflammation of sulfur mustard (SM) exposed guinea pigs was examined. Materials and methods Guinea pigs were exposed to diluent solution (control group), inhaled SM (SME group), SME treated with Nigella sativa (SME + N), SME treated with dexamethasone (SME + D) and SME treated with both drugs (SME + N + D), ( n = 7 for each group). TR to methacholine, total white blood cell (WBC) and differential WBC count of lung lavage, and serum cytokines were measured 14 days post-exposure. Results The values of TR, eosinophil, monocyte, lymphocyte, interleukine-4 (IL-4) and interferon gamma (IFN-γ) of SME group were significantly higher than those of controls ( p < 0.05 to p < 0.001). The TR in SME + N, SME + D and SME + N + D was significantly lower compared to that of SME group ( p < 0.01 for all cases). The percentage of eosinophil in SME + D, and the percentage of monocyte in SME + N + D ( p < 0.05 to p < 0.01) were significantly lower than those in SME group. The neutrophil number was decreased in SME + N and SME + N + D groups compared to SME animals ( p < 0.05 to p < 0.01). IL-4 levels in serum of SME + N ( p < 0.01), SME + D ( p < 0.05), SME + N + D ( p < 0.01) and IFN-γ in SME + N ( p < 0.05) were greater than those in SME animals. Conclusions These results showed a preventive effect of Nigella sativa on TR and lung inflammation of SM exposed guinea pigs.

Effect of acute cold exposure on lung perfusion and tracheal smooth muscle contraction in rabbit

Acute exposure to cold temperature can affect the respiratory system of those exposed to extreme weather and induces asthma in asthmatic patients. However, the effect on lung perfusion and the pulmonary circulation was not addressed in any previous study. The present study investigates the effects of acute cold exposure on tracheal smooth muscle and lung perfusion. New Zealand White rabbits were used in these experiments. For in vitro experiments, isolated tracheal segments were suspended in organ baths containing Krebs' solution for isometric tension recording. Tissue response to cooling from 37 to 4°C was examined. For in vivo experiments, the rabbits were kept in a cold room (4°C) for 1h. Lung perfusion scintigraphy was performed at the end of this period. Each rabbit was injected with 74MBq (2mCi) technetium-99m macroaggregated ((99m)Tc MAA). Perfusion studies were done by using Gamma camera equipped with a low-energy, high-resolution, parallel-hole collimator interfaced with a computer. Static images were acquired 5min after administration of the radiotracer. Cooling induced a rapid and reproducible contraction in the tracheal smooth muscle. Rabbits exposed to cold temperature had lesser lung perfusion than controls using radionuclide perfusion study. Our results highlight the response of tracheal muscle and pulmonary circulation to cold exposure. These results indicate that cooling induced contraction of the trachea and decreased pulmonary circulation and lung perfusion. This summation of acute cooling for tracheal smooth muscle and pulmonary circulation seems to be the reason for the severe cooling-induced contraction.

Role of Cyclooxygenase Isoforms and Nitric-Oxide Synthase in the Modulation of Tracheal Motor Responsiveness in Normal and Antigen-Sensitized Guinea Pigs

The effects of selective cyclooxygenase (COX) isoform (COX-1, COX-2) inhibition, alone or in combination with nitric-oxide synthase (NOS) blockade, on in vitro tracheal muscle responsiveness to histamine were investigated in healthy and ovalbumin (OVA)-sensitized guinea pigs. Immunohistochemistry showed that COX-1 and COX-2 are constitutively present in normal guinea pig trachea, particularly in the epithelial layer, and that COX-2 expression is enhanced in OVA-sensitized animals both in epithelial and subepithelial tissues. In normal guinea pigs, SC-560 [5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-trifluoromethylpyrazole] (COX-1 inhibitor) or DFU [5,5-dimethyl-3-(3-fluorophenyl)-4-(4-methylsulphonyl)phenyl-2(5H)-furanone] (COX-2 inhibitor) significantly increased the contractile response to histamine, these effects being not additive. NOS inhibition by l-N(G)-nitro-arginine methyl ester (l-NAME) did not affect histamine-induced contraction but reversed the increase caused by COX-1 blockade while not modifying the enhancement associated with COX-2 inhibition. In guinea pigs subjected to OVA sensitization and challenge, COX-2, but not COX-1, inhibition enhanced the motor responses to histamine without any influence by l-NAME. In normal, but not in sensitized animals, the removal of epithelial layer from tracheal preparations abolished the enhancing action of DFU on histamine-mediated contraction. A COX-2-dependent release of prostacyclin (PGI(2)), but not prostaglandin E(2), was observed in tracheal tissues from normal and OVA-sensitized guinea pigs. In conclusion, both COX-1 and COX-2 are constitutive in guinea pig trachea, and COX-2 expression is enhanced by OVA sensitization; in normal animals, epithelial COX-2 exerts a PGI(2)-dependent inhibitory control on tracheal contractility, and this isoform is subjected to upstream regulation by epithelial COX-1 and NOS through a complex interplay; and following antigen sensitization, the inhibitory control on tracheal contractility is maintained by COX-2 induced at subepithelial cell sites.

A comparative study on cockroach and ovalbumin sensitizations and challenge responses in Hartley guinea-pigs

The role of allergens in asthmatic inflammation is not clearly understood. To elucidate the mechanism of cockroach allergen (CRa)-induced airway disease, we studied three groups of Hartley guinea-pigs sensitized to control, ovalbumin (OA) or CRa. Parameters measured were anaphylactic antibodies by allergy skin test (AST), PCA assay and Western blot, changes in specific airway resistance (SRaw), analysis of bronchoalveolar lavage (BAL) and contracture responses of tracheal muscle (TSM) to non-specific and specific stimuli, in vitro. Both OA and CRa animals showed a similar allergic sensitization (AST and PCA), while Western blot identified several reaginic bands in CRa group compared to a single band in OA group. SRaw illustrated that CRa induce dual-asthmatic responses (4/6) in the CRa group, whereas OA induce only an early asthmatic response (3/6) in the OA group ( P<0.01). The average total leukocytes in BALF of the CRa were 27.0×10 6, mostly neutrophils and eosinophils, while those of the OA showed 3.5×10 6, mostly eosinophils, respectively ( P<0.0001). TSM responses to non-specific stimuli were similar in both groups ( P>0.1), while the antigen-specific TSM contractions were more brisk in the OA group than those of CRa group ( P<0.001). Thus, the study indicates that both CRa and OA sensitize guinea-pigs, yet CRa induces more severe and persistent late-phase inflammation than OA. This appears to be related to an influx of neutrophils rather than anaphylactic bronchospasm.

Subchronic Exposure to Diisocyanates Increases Guinea Pig Tracheal Smooth Muscle Responses to Acetylcholine

Objective: In order to study the threshold concentrations of isocyanates (IC) for induction of lung disorders, constrictive responses of tracheal smooth muscles to acetylcholine (ACH) in guinea pigs with and without diisocyanate [toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI) and diphenylmethane diisocyanate (MDI)] exposure were investigated. Methods: An IC-induced increase in smooth muscle responsiveness was studied by measuring cumulative ACH dose responses (10^–10 to 10^–4 M ACH). Basal ACH dose-response curves, measured twice in intervals of 1 h using tracheal preparations of 11 guinea pigs previously not exposed to IC, were reproducible. Results: Subchronic in vivo exposures to TDI, HDI, and MDI atmospheres of 10 and 20 parts per billion (ppb) on 5 consecutive days led to significantly (p < 0.05) increased ACH responsiveness of tracheal smooth muscle, whereas concentrations of 2.5 and 5 ppb were not effective. Exposure to HDI atmospheres of 10 ppb for 1, 2, 4, or 8 weeks resulted in a time-dependent increase in ACH responses (p < 0.05) of guinea pig tracheal smooth muscle. Increased tracheal muscle responses to ACH were transient since tracheal preparations from animals exposed to 10 and 20 ppb MDI for 4 weeks and with an exposure-free interval of 8 weeks before preparation did not show enlarged ACH responses, which were present in preparations at the end of the exposure period (p < 0.05). Exposure to low IC concentrations as present in workplaces cause increased ACH responsiveness of guinea pig tracheal smooth muscle. The increased responsiveness of the airways seems to be largely reversible, since normal responses were found after 8 weeks of IC avoidance. Conclusion: Reversibility of IC-induced airway hyperresponsiveness is of great occupational and preventive medical importance. Workers with acquired airway hyperresponsiveness might escape lung damage if the changes are detected in an early stage before alterations in lung function are in a chronic stage.

Contribution of brainstem hypoperfusion to the tracheal and phrenic nerve responses to high-pressure lung inflation in the dog

Lung inflation to high airway pressure is known to produce tracheal constriction following an initial dilation. This is attributed to stimulation of various pulmonary receptors. In an attempt to find cause of this response, we investigated in 20 decerebrated, tracheostomized and paralyzed dogs changes in the tracheal smooth muscle tension, arterial pressure and the phrenic nerve activity to high-pressure lung inflation. A high-pressure lung inflation evoked a contraction of tracheal smooth muscle following its short-lasting relaxation, and a persistent hypotension. After hilar denervation which eliminated all pulmonary afferents, a high-pressure lung inflation still evoked contraction of tracheal smooth muscle (an increase of 3.7 times) and augmented amplitude and frequency of phrenic bursts. Bilateral transections of sympathetic fibers to the lung, or blockade of arterial perfusion to the carotid sinus and denervation of the carotid sinus bilaterally did not alter the tracheal muscle and phrenic responses to a high-pressure lung inflation. We further found that severe hypotension alone caused similar responses of the tracheal smooth muscle contraction and augmented phrenic activity. Finally, when blood supply to the brainstem was transiently obstructed by clamping both the vertebral and internal carotid arteries bilaterally, the same responses were observed. In contrast, when blood hypoperfusion to the brainstem was prevented by means of extracorporeal circulation, a high-pressure lung inflation failed to evoke such contraction of tracheal smooth muscle and or increased phrenic activity. After transection of the vagus nerves bilaterally at the cervical level the tracheal muscle response to lung inflation was abolished but that of phrenic nerve was preserved. We concluded that the tracheal smooth muscle contraction and phrenic responses induced by high-pressure lung inflation may be in part attributed to brainstem hypoperfusion.

Effects of neutrophil depletion and repletion on PAF-induced hyperresponsiveness of canine trachea.

Platelet-activating factor (PAF) has been implicated as a mediator of airway hyperresponsiveness. PAF, infused intra-arterially into the canine cervical trachea, causes adherence of neutrophils to vascular endothelium, increases vascular permeability, and increases the responsiveness of tracheal muscle to parasympathetic stimulation. We hypothesized that the increase in airway responsiveness induced by PAF in this model depends on the presence of neutrophils. To test this hypothesis, we perfused a cervical tracheal segment with autologous blood depleted of leukocytes or with similar leukocyte-depleted blood that had been repleted with its neutrophils. Fifteen minutes after the onset of perfusion with either leukocyte-depleted or neutrophil-repleted blood, PAF infusion was begun into the tracheal arterial vasculature. The contractile response of the tracheal muscle to parasympathetic stimulation was measured before and 15 and 30 min after the onset of PAF infusion. PAF did not significantly change the response of tracheal muscle during perfusion with neutrophil-depleted blood but increased the response of tracheal muscle during perfusion with neutrophil-repleted blood. We conclude that the increase in canine tracheal muscle response induced by intra-arterial PAF depends on neutrophils.

Effect of NZ-107, a newly synthesized pyridazinone derivative, on antigen-induced contraction of human bronchial strips and histamine release from human lung fragments or leukocytes.

The effects of a newly synthesized pyridazinone derivative, NZ-107, 4-bromo-5-(3-ethoxy-4-methoxybenzylamino)-3(2H)-pyridazinone, and two well-known antiasthmatic drugs, amlexanox (orally active disodium cromoglycate-like drug) and disodium cromoglycate (DSCG) on antigen-, histamine- and leukotriene C4 (LTC4)-induced constriction of isolated human tracheal muscle, and histamine release from human lung tissues and leukocytes were investigated in vitro. In some experiments, salbutamol was used as a reference drug. NZ-107 inhibited antigen-, histamine- and LTC4-induced contraction of tracheal muscle. Amlexanox and DSCG did not affect the contractile response of tracheal muscle caused by each stimulant. Salbutamol inhibited antigen-induced contraction of tracheal muscle. NZ-107, amlexanox, DSCG and salbutamol clearly inhibited the antigen-induced release of histamine and LTC4 from human lung tissue. The antigen-induced histamine release from atopic human leukocytes was inhibited by NZ-107 and amlexanox, but not by DSCG. Pretreatment with IL-3 did not alter antigen-induced contraction of tracheal muscle and histamine release from lung tissue, but antigen- or calcium ionophore A 23187-induced histamine release from leukocytes was clearly enhanced. Amlexanox inhibited the IL-3-induced enhancement of histamine release from leukocytes in the case of both stimuli, but NZ-107 and DSCG had no effect. These data suggest that NZ-107 has potent anti-allergic actions based on the inhibition of antigen-induced contraction of human tracheal muscle and mediator release from human lung tissue and leukocytes.

Effect of Cooling on the Responsiveness of Canine Tracheal Muscle

Airway cooling causes bronchoconstriction in many persons who have asthma. To determine the direct effect of cooling on the response of tracheal muscle to parasympathetic and muscarinic stimuli in situ, the temperature of a segment of canine cervical trachea was adjusted to 37 degrees, 30 degrees, or 25 degrees C by superfusing temperature-controlled saline over its epithelial surface. The contractile response of the tracheal muscle to electrical stimulation of the vagus nerves and to intra-arterial acetylcholine was then determined. Cooling the segment to 25 degrees C decreased the contraction induced by parasympathetic stimulation. However, cooling did not alter the contraction induced by intra-arterial acetylcholine. Parallel studies were conducted in vitro using nine excised tracheal muscle strips taken from the same section of trachea in three additional dogs. Cooling the tracheal muscle to 25 degrees C in vitro increased the maximal contraction induced by both electrical field stimulation and by acetylcholine. Thus, cooling in situ does not alter the response of tracheal muscle to muscarinic stimuli and inhibits the response to parasympathetic stimuli. These data indicate that augmentation of the tracheal muscle response elicited by cooling in vitro does not reflect the response in situ. They suggest that a direct effect of cooling on airway smooth muscle response to parasympathetic and muscarinic stimuli does not account for cooling-induced bronchoconstriction in vivo.

Cyclooxygenase inhibitors increase canine tracheal muscle response to parasympathetic stimuli in situ

To determine whether cyclooxygenase inhibitors alter parasympathetic control of airway smooth muscle in situ, we pretreated anesthetized dogs with intravenous indomethacin, meclofenamate, or normal saline and measured the isometric contraction of tracheal muscle in response to electrical stimulation of the vagus nerves. Indomethacin and meclofenamate increase the response of airway smooth muscle to parasympathetic stimulation. In subsequent experiments to determine the site of action of cyclooxygenase inhibitors, we found that indomethacin does not alter the response of tracheal muscle to intra-arterial acetylcholine (a muscarinic agonist) but does augment the response to intra-arterial dimethylpiperaziniumiodide (a nicotinic agonist). Moreover, the response to parasympathetic stimulation after pretreatment with a combination of indomethacin and BW755C (a combined cyclooxygenase-lipoxygenase inhibitor) does not differ significantly from the response after indomethacin or meclofenamate alone. We conclude that cyclooxygenase inhibitors increase the sensitivity of the contractile response of tracheal smooth muscle to parasympathetic stimulation, that they exert their effect on the postganglionic parasympathetic neuron, and that their effect is prejunctional. The effect appears secondary to a decrease in cyclooxygenase products rather than to an increase in lipoxygenase products. These findings suggest that endogenous cyclooxygenase products may modulate parasympathetic control of airway smooth muscle in vivo. They may relate to the mechanisms that underlie airway hyperresponsiveness, by which mediators of inflammation modulate airway responsiveness and by which nonsteroidal anti-inflammatory drugs induce severe bronchoconstrictor responses in some persons who have asthma.

Differential calcium movements induced by agonists in guinea pig tracheal muscle

The effects of high potassium, carbachol and histamine on tension responses and 45Ca fluxes in tracheal smooth muscle were examined. Calcium depletion or nitrendipine (10(-8) M) inhibited potassium-induced contractile responses more than those obtained with either histamine or carbachol, whereas Sr2+ inhibited mainly responses to histamine or carbachol. The Ca2+ entry facilitator, CGP 28392 (3 X 10(-6) M), potentiated contractions induced only by potassium. Uptake of 45Ca in guinea pig tracheal muscle can be separated into high and low affinity components. The 45Ca efflux rate from tracheal muscle into a La3+-substituted solution was over four-fold higher than in other smooth muscles. Potassium, carbachol and histamine induced sustained increases in 45Ca efflux into solutions containing 1.5 mM Ca2+; only transient increases in 45Ca efflux with carbachol and histamine were obtained after Ca2+ depletion. These agonists elicit contractile responses in tracheal muscle by selectively mobilizing different cellular and extracellular Ca2+ components.

Mechanisms of response to antigen in isolated guinea pig trachea after active sensitization.

A study was made of the responses of guinea pig tracheal muscle in vitro after sensitization by either subcutaneous or intraperitoneal administration of antigens. No difference was observed in the responses of strips from either group to cumulative or single doses of antigen. The responses of the tracheal muscle to antigen were analyzed as to magnitude (relative to maximal carbachol responses), time to peak contraction, and time to half decay. Pyrilamine, an H1-receptor antagonist, slowed the onset of contraction and decay. The latter result suggested a role for histamine in controlling the release of or the response to other mediators and the former was consistent with previous evidence that histamine release augments the initial response. An inhibitor of 5'-lipoxygenase and cyclooxygenase (5,8,11,14-eicosatetraynoic acid), indomethacin, and the slow-reacting substance of anaphylaxis (SRS-A) antagonist FPL-55712 all shortened the time to half decay of the contraction, presumably by different mechanisms. The release and actions of leukotrienes may have been limited by eicosatetraynoic acid and FPL55712, respectively, but the action of indomethacin suggests a modulating role for prostanoids in leukotriene action or release. Nordihydroguaiaretic acid both reduced the maximum response and accelerated decay of this response, suggesting that the maximum response depends upon leukotriene release. Cromoglycate, methysergide, and an inhibitor of thromboxane synthetase were without effect. Both tetrodotoxin and atropine delayed the time to peak contraction and tetrodotoxin also delayed the decay of the contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of leukotriene D4 and antagonists of arachidonic acid metabolism and calcium entry on guinea pig tracheal muscle responsiveness

We studied the effects of antagonists of arachidonic acid metabolism and calcium entry on the responsiveness of airway smooth muscle to acetylcholine (ACh), potassium and norepinephrine.Responsiveness in vitro was assessed by measuring isometric contraction of guinea pig trachealis muscle upon chemical stimulation. We found that indomethacin potentiated the response of airway muscle to ACh and KCl, but not to norepinephrine. The indomethacin-induced potentiation observed was inhibited by both BW 755C and nifedipine. As occurred with indomethacin pretreatment, we also found that a noncontractile concentration of leukotriene D4 (LTD4) potentiated the responsiveness of tracheal muscle to both ACh and KCl. Our data suggest that indomethacin- and LTD4-potentiation of guinea pig airway muscle responsiveness to certain bronchoconstrictors may be mediated, at least in part, by enhanced extracellular Ca++ entry.

Effect of temperature (Temp.) and nifedipine on tracheal muscle responses to methacholine (Meth.)

Effect of temperature (Temp.) and nifedipine on tracheal muscle responses to methacholine (Meth.)

The effects of arachidonic acid, indomethacin and SC-19220 on guinea-pig tracheal muscle tone

The effects on guinea-pig tracheal muscle of a prostaglandin synthesis inhibitor, indomethacin, antagonist, SC-19220, and precursor, arachidonic acid have been studied in order to investigate the possible role of prostaglandins in the maintenance of respiratory smooth muscle tone. Indomethacin reduced the resting tone of the muscle, and increasing concentrations reduced the response to arachidonic acid without affecting the response to acetylcholine. Prostaglandins E 2 and F 2α caused contractions of indomethacin-relaxed muscle, and tachyphylaxis was induced by repeated exposure of the muscle to these agonists, but not to arachidonic acid. The prostaglandin antagonist, SC-19920 relaxed the muscle, and abolished its response to a standard dose of prostaglandin E 2. Increasing concentrations of SC-19220 reduced the responses to both arachidonic acid and large doses of prostaglandins E 2. The responses of tracheal muscle to arachidonic acid are concluded to be partly due to prostaglandin synthesis, supporting the hypothesis that this process maintains tracheal muscle tone.

The tracheal strip: Observations on the response of tracheal muscle

1. 1. A modification of the tracheal chain preparation is described. This modification is easier to prepare, it is more sensitive, and it can be used in comparative studies using the trachea of one animal. 2. 2. The response of tracheal muscle to various drugs is described. Further contraction occurs with histamine after maximal contraction with antigen. Hydrocortisone hemisuccinate did not relax or prevent tracheal muscle contraction from histamine or egg albumin in a sensitized guinea pig. 3. 3. Guinea pig trachea may be passively sensitized in vivo with rabbit anti-egg-albumin serum.