Ansa Cervicalis Stimulation: A New Direction in Neurostimulation for OSA.

BACKGROUND: Hypoglossal nerve stimulation (HNS) is an alternative treatment option for patients with OSA unable to tolerate positive airway pressure but implant criteria limit treatment candidacy. Previous research indicates that caudal tracheal traction plays an important role in stabilizing upper airway patency. RESEARCH QUESTION: Does contraction of the sternothyroid muscle with ansa cervicalis stimulation (ACS), which pulls the pharynx caudally via thyroid cartilage insertions, increase maximum inspiratory airflow (VImax)? STUDY DESIGN AND METHODS: Hook-wire percutaneous electrodes were used to stimulate the medial branch of the right hypoglossal nerve and right branch of the ansa cervicalis innervating the sternothyroid muscle during propofol sedation. VImax was assessed during flow-limited inspiration with a pneumotachometer. RESULTS: Eight participants with OSA were studied using ACS with and without HNS. Compared with baseline, the mean VImax increase with isolated ACS was 298%, or 473 mL/s (95% CI, 407-539). Isolated HNS increased mean VImax from baseline by 285%, or 260 mL/s (95% CI, 216-303). Adding ACS to HNS during flow-limited inspiration increased mean VImax by 151%, or 205 mL/s (95% CI, 174-236) over isolated HNS. Stimulation was significantly associated with increase in VImax in both experiments (P < .001). INTERPRETATION: ACS independently increased VImax during propofol sedation and drove further increases in VImax when combined with HNS. The branch of the ansa cervicalis innervating the sternothyroid muscle is easily accessed. Confirmation of the ansa cervicalis as a viable neurostimulation target may enable caudal pharyngeal traction as a novel respiratory neurostimulation strategy for treating OSA.

Curcumin analogs (B2BrBC and C66) supplementation attenuates airway hyperreactivity and promote airway relaxation in neonatal rats exposed to hyperoxia.

BACKGROUND: This study was undertaken to test the hypothesis that the newly synthesized curcuminoids B2BrBC and C66 supplementation will overcome hyperoxia-induced tracheal hyperreactivity and impairment of relaxation of tracheal smooth muscle (TSM). MATERIALS AND METHODS: Rat pups (P5) were exposed to hyperoxia (>95% O2 ) or normoxia for 7 days. At P12, tracheal cylinders were used to study in vitro contractile responses induced by methacholine (10-8 -10-4 M) or relaxation induced by electrical field stimulation (5-60 V) in the presence/absence of B2BrBC or C66, or to study the direct relaxant effects elicited by both analogs. RESULTS: Hyperoxia significantly increased contraction and decreased relaxation of TSM compared to normoxia controls. Presence of B2BrBC or C66 normalized both contractile and relaxant responses altered by hyperoxia. Both, curcuminoids directly induced dose-dependent relaxation of preconstricted TSM. Supplementation of hyperoxic animals with B2BrBC or C66, significantly increased catalase activity. Lung TNF-α was significantly increased in hyperoxia-exposed animals. Both curcumin analogs attenuated increases in TNF-α in hyperoxic animals. CONCLUSION: We show that B2BrBC and C66 provide protection against adverse contractility and relaxant effect of hyperoxia on TSM, and whole lung inflammation. Both analogs induced direct relaxation of TSM. Through restoration of catalase activity in hyperoxia, we speculate that analogs are protective against hyperoxia-induced tracheal hyperreactivity by augmenting H2 O2 catabolism. Neonatal hyperoxia induces increased tracheal contractility, attenuates tracheal relaxation, diminishes lung antioxidant capacity, and increases lung inflammation, while monocarbonyl CUR analogs were protective of these adverse effects of hyperoxia. Analogs may be promising new therapies for neonatal hyperoxic airway and lung disease.

Metabolomic fingerprinting of Cissampelos sympodialis Eichler leaf extract and correlation with its spasmolytic activity.

ETHNOPHARMACOLOGICAL RELEVANCE: Cissampelos sympodialis Eichler (Menispermaceae) is popularly used in northeastern Brazil for the treatment of respiratory diseases such as bronchitis and asthma. Despite many pre-clinical pharmacological studies, the compounds mediating the anti-asthma activity of polar extracts of Cissampelos sympodialis leaves have not been definitively identified. AIM OF THE STUDY: Aim of the study: The aim of the study was to investigate the correlation between the bioactivity of polar extracts prepared from the leaves of C. sympodialis and the chemical composition using a 1H-NMR-based metabolomics approach. MATERIAL AND METHODS: The metabolic profile of the leaf polar extract during different phenological stages of the plant was investigated using 1H NMR spectroscopy while simultaneously screening for spasmolytic activity using guinea-pig tracheal preparations. The content of the alkaloids previously implicated in the bioactivity of Cissampelos sympodialis was determined by HPLC. RESULTS: PCA analysis of the 1H NMR data discriminated the extracts from different plant phenological stages. The contents of the major alkaloids decrease (from 2 ± 0.32 µg/mL for warifteine and 1 ± 0.14 µg/mL for methylwarifteine) to undetectable levels from 90 (CsL90 extract) and 120 (CsL120) days onwards for warifteine and methylwarifteine, respectively. All six extracts relaxed the trachea pre-contracted with carbachol, but the CsF210 extract was more potent (EC50 = 74.6 ± 7.9 µg/mL) compared to both CsL90 extracts and CsL180 in the presence of functional epithelium. PLS regression analysis of 1H-NMR spectral data demonstrated that the spasmolytic activity was better correlated with signals for flavonol derivatives. CONCLUSIONS: Our data challenge the idea that warifteine and methylwarifteine mediate the spasmolytic activity of the polar extract of C. sympodialis leaves.

Lippia alnifolia essential oil induces relaxation on Guinea-pig trachea by multiple pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: Lippia alnifolia Mart. & Schauer, known as "alecrim-do-mato", "alecrim-de-vaqueiro" and "pedrécio", is used in folk medicine as antiseptic and to treat diseases that affect respiratory system, like bronchitis and asthma. AIM OF THE STUDY: The aim of this work was to investigate the spasmolytic activity and relaxant mechanism of the Lippia alnifolia essential oil (EOLA) on isolated guinea-pig trachea and to correlate with its use in folk medicine. MATERIALS AND METHODS: Leaves from L. alnifolia were collected in Pico das Almas, Chapada Diamantina, situated in the city of Rio de Contas, Bahia, Brazil. EOLA was extracted by hydrodistillation, analyzed by GC/FID and GC/MS and the volatile constituents were identified. Spasmolytic activity was assayed in isolated guinea-pig trachea pre-contracted with carbachol 1 µM or histamine 10 µM. Relaxant mechanism of EOLA was determined comparing concentration-response curves in the presence or absence of different blockers. RESULTS: Chemical analysis revealed the presence of carvone (60 ±â€¯0.8%) as major constituent. EOLA (1-243 µg/mL) relaxed isolated guinea-pig trachea pre-contracted with carbachol 1 µM [EC50 = 53.36 (44.75-63.51) µg/mL] or histamine 10 µM [EC50 = 5.42 (4.42-6.65) µg/mL]. The pre-incubation of 4-aminopyridine in histamine-induced contractions did not alter significantly the relaxant effect of EOLA. However, the presence of cesium chloride, glibenclamide, tetraethylammonium, propranolol, indomethacin, dexamethasone, hexamethonium, atropine, L-NAME, methylene blue or ODQ reduced EOLA relaxant effect. EOLA 18 µg/mL pre-incubation in calcium-free medium reduced histamine-evoked contractions, but did not alter histamine contractions in the presence of nifedipine. CONCLUSIONS: Lippia alnifolia essential oil has spasmolytic activity on isolated guinea-pig trachea and its mechanism of action possibly involves the activation of multiple signal transduction pathways, which culminate in potassium channels activation and cytosolic calcium reduction.

Glottis motion effects on the particle transport and deposition in a subject-specific mouth-to-trachea model: A CFPD study.

BACKGROUND: Computational Fluid-Particle Dynamics (CFPD) models have been employed to predict lung aerosol dynamics for decades, estimating the delivery efficiency of inhaled drugs into the tracheobronchial tree. However, existing CFPD models assume the glottis is static during the breathing cycle. Failing to capture the dynamic motion of the glottis may introduce significant errors in drug deposition estimations. METHODS: A novel CFPD model was developed with the capability of modeling the glottis motion using the dynamic mesh method. To explore the causal relationships between the glottis motion and the inhaled drug particle dynamics, simulations were performed to compare static and different dynamic glottis models in a subject-specific mouth-to-trachea geometry under idealized sinusoidal and realistic breathing waveforms. By defining the movement of each node in the glottis region using a generalized glottis motion function (GGMF) validated with clinical data, the abduction and adduction of the glottis were accurately described. Transient transport characteristics of inhaled particle-laden airflows were investigated and analyzed, including the glottis motion effect on the inhaled particles with the aerodynamic diameters from 0.1 to 10 µm. RESULTS: Numerical results indicate that the static glottis assumption deviates the total deposition fraction predictions by more than 8% in relative differences. Compared with the CFPD models with the static glottis assumption, the dynamic glottis model can more realistically predict the complexity of the secondary flows near the vocal fold and the resultant particle depositions. Inter-subject variabilities of the glottis motion patterns were observed, and their influences on particle transport dynamics are not uniform. Parametric analyses also demonstrate that the maximum deformation ratio of the glottis is a key feature to describe whether the glottis motion can enhance or reduce particle depositions in the mouth-to-trachea region, over the static glottis model. CONCLUSIONS: The glottis motion shows a significant influence on the accuracy of predicting inhaled particle dynamics, and it should be integrated into CFPD simulations validated by subject-specific glottis motion data from clinical studies in the future. Furthermore, the proposed dynamic glottis model has been demonstrated to be a computationally effective method to recover the physiologically realistic motions of the glottis, and ready to be added into the next-generation holistic virtual lung modeling approach.

Irreversible metabolic abnormalities following chronic upper airway loading.

STUDY OBJECTIVES: Treatment of obstructive sleep apnea increases obesity risk by an unclear mechanism. Here, we explored the effects of upper airway obstruction and its removal on respiratory homeostasis, energy expenditure, and feeding hormones during the sleep/wake cycle from weaning to adulthood. METHODS: The tracheas of 22-day-old rats were narrowed, and obstruction removal was performed on post-surgery day 14. Energy expenditure, ventilation, and hormone-regulated feeding were analyzed during 49 days before and after obstruction. RESULTS: Energy expenditure increased and body temperature decreased in upper airway obstruction and was only partially recovered in obstruction removal despite normalization of airway resistance. Increased energy expenditure was associated with upregulation of ventilation. Decreased body temperature was associated with decreased brown adipose tissue uncoupling protein 1 level, suppressed energy expenditure response to norepinephrine, and decreased leptin level. Upper airway obstructed animals added less body weight, in spite of an increase in food intake, due to elevated hypothalamic orexin and neuropeptide Y and plasma ghrelin. Animals who underwent obstruction removal fed more due to an increase in hypothalamic neuropeptide Y and plasma ghrelin. CONCLUSIONS: The need to maintain respiratory homeostasis is associated with persistent abnormal energy metabolism and hormonal regulation of feeding. Surgical treatment per se may not be sufficient to correct energy homeostasis, and endocrine regulation of feeding may have a larger effect on weight change.

The contribution of beta-2 adrenergic, muscarinic and histamine (H1) receptors, calcium and potassium channels and cyclooxygenase pathway in the relaxant effect of Allium cepa L. on the tracheal smooth muscle.

ETHNOPHARMACOLOGICAL RELEVANCE: There are report regarding therapeutic effects for Allium cepa L. (A. cepa) in Iranian traditional medicine and the plant has showed anti-inflammatory, anti-allergic, anti-hyperglycemic, antioxidant, anti-cancer, anti-hypertension, anti-hypercholesterolemia and anti-asthmatic activities in previous studies. AIM OF THE STUDY: In this study, the contribution of ß2 adrenergic, muscarinic and histamine (H1) receptors, calcium and potassium channels, and cyclooxygenase pathway in the relaxant effect of A. cepa extract on tracheal smooth muscle (TSM) was assessed. MATERIALS AND METHODS: TSM was contracted by KCl (60 mM) or methacholine (10 µM) for 5 min and cumulative concentrations of A. cepa extract (2, 4, 8, 16, 32 and 64 mg/ml) were added to organ bath every 5 min. Theophylline (0.2, 0.4, 0.6 and 0.8 mM) as positive control, and saline (1 ml) as negative control were also examined in non-incubated tissues. The relaxant effect of A. cepa extract was examined on non-incubated and incubated TSM with propranolol, chlorpheniramine, diltiazem, atropine, glibenclamide and indomethacin. RESULTS: A. cepa showed concentration-dependent relaxant effects on non-incubated TSM contracted by KCl (60 mM) or methacholine (10 µM), (P < 0.01 to p < 0.001). There was no significant difference in the relaxant effects of A. cepa between non-incubated and incubated tissues with glibenclamide, atropine, chlorpheniramine and indomethacin. The plant extract showed significant lower relaxant effects in incubated TSM with propranolol and diltiazem compared to non-incubated tissues. EC50 values of A. cepa extract in incubated TSM with propranolol and diltiazem were significantly lower than non-incubated tissues (p < 0.001 and p < 0.05, respectively). The relaxant effects of different concentrations of the extract of A. cepa were not significantly different with those of theophylline. The concentrations of A. cepa extract and theophylline were significant correlated with their relaxant effects (p < 0.05 to p < 0.001). In incubated TSM with propranolol and diltiazem, concentration ratio minus one (CR-1) values was positive (2.65 ±â€¯0.63 and 1.28 ±â€¯0.43 respectively). CONCLUSION: The A. cepa extract showed relatively potent relaxant effect on TSM which was comparable to the effect of theophylline. The results showed that ß2-adrenergic stimulatory and/or calcium channel blockade are the possible mechanisms for the relaxant effects of the plant.

The Stimulatory Effects of Medicinal Plants on ß2-adrenoceptors of Tracheal Smooth Muscle.

Medicinal plants have been identified and used as primary sources in prevention and treatment of pulmonary diseases (mainly obstructive pulmonary diseases) from ancient times due to various pharmacological activities. In this review, the stimulatory effects of extracts, some fractions and constituents of medicinal plants on ß2-adrenoceptors which could be used as possible therapeutic agents in the future were reviewed. Various databases including; Medline, PubMed, ScienceDirect, Scopus, and Google Scholar were searched using stimulatory effect, ß2-adrenoceptors, possible mechanism, tracheal smooth muscle (TSM), medicinal plants and their constituents as keywords from 1985 to 2017. All studied plants including; Nigella sativa, Rosa damascena, Thymus vulgaris, Carum copticom, Carum carvi, Zataria multiflora, Crocus sativus, Cuminum cyminum, Liomnia acidissima, Portulaca oleraceae, Satureja hortensis, Ephedra sinica and Achillea millefolium showed relaxant effect on tracheal smooth muscle with a stimulatory effect on ß2-adrenoceptors mechanism. The studied plants and their constituents could be of therapeutic value in clinical practice as a bronchodilatory drug by ß2-adrenoceptors stimulatory mechanism for treatment of obstructive pulmonary diseases.

Pharmacological basis for the medicinal use of Alcea rosea in airways disorders and chemical characterization of its fixed oils through GC-MS.

Alcea rosea L. also known as Althea rosea belongs to the Malvaceae family. This medicinal herb, traditionally used to treat several conditions including airway disorders like asthma and chronic bronchitis. This study evaluated the bronchodilatory effects and possible mechanism of A. rosea on guinea-pig tracheal tissues. Moreover lipophilic profiling of A. rosea has been carried out by using Gas-Chromatography-Mass-Spectrometry. A total of 19 compounds have been identified from the plant, n-hexane fraction. These compounds have been further confirmed from their Van den Dool and Kratz (I) Indices. Major class of metabolite identified from the plant includes fatty acid, saturated and unsaturated fatty acid esters. Hydrocarbons have also been detected from the n-hexane fraction. These fatty acid esters have not been reported previously by GC-MS and were identified first time from the flowers of Alcea rosea. In-vitro experiments were performed on guinea-pig tracheal tissues, mounted in Kreb's solution at 37°C and bubbled with carbogen. In isolated guinea-pig trachea, A. rosea inhibited carbamylcholine and K+ (80 mM)-induced contractions, potentiated isoprenaline concentration-response curves (CRCs) and suppressed Ca2+ CRCs. These results suggest that A. rosea cause bronchodilation through dual inhibition of phosphodiesterase enzyme and Ca2+ influx, which substantiate its potential in airways disorders.

Airway smooth muscle relaxant activity of Cordia dodecandra A. DC. mainly by cAMP increase and calcium channel blockade.

ETHNOPHARMACOLOGICAL RELEVANCE: The fight against chronic respiratory diseases needs the exploration of new active compounds with properties that contribute to diminish the symptoms or resolve the disease alongside current therapy. MATERIALS AND METHODS: Eight extracts obtained from the bark and leaves of a Mayan medicinal plant used to treat asthma, Cordia dodecandra A. DC., were investigated for their relaxant effect on rat isolated tracheal rings pre-contracted with carbachol [1 µM]. The underlying functional mode of action of the most effective extract was assessed and the chromatographic fingerprints of more active extracts were analyzed. RESULTS: The dichloromethane bark extract (DECd-b) was the most effective and potent (Emax= 87.57 ±â€¯1.32 %; EC50 = 392.7 ±â€¯5.18 µg/mL). DECd-b relaxant effect was maximized in presence of isoproterenol (ß-adrenergic agonist, [10 µM]) and theophylline (phosphodiesterase unspecific inhibitor, [10 µM]). DECd-b also showed efficient relaxation of KCl [80 mM]-induced contraction and inhibition of CaCl2-induced contraction. Pre-incubation with propranolol (non-selective ß-adrenergic antagonist, [10 µM]), SQ22536 (adenylyl cyclase inhibitor; [100 µM]), ODQ (guanylyl cyclase inhibitor; [10 µM]), l-NAME (nitric oxide synthase inhibitor; [10 µM]), indomethacin (a cyclooxygenase unspecific inhibitor; [10 µM]), glibenclamide (ATP-sensitive potassium channel blocker; [10 µM]) and 2-aminopyridine (voltage-gated potassium channel blocker [100 µM]) did not modify the DECd-b relaxant-effect curve. The chromatographic analysis of DECd-b suggests the cordiaquinones presence with double conjugated bounds such as menaquinone. CONCLUSIONS: Results suggest that DECd-b induces relaxation mainly by cAMP increase and Ca2+ channel blockade. The chromatographic profiles and UV spectrum of DECd-b and HECd-l suggest the presence of molecules with structure of meroterpenoid naphthoquinones. This work report scientific evidence of C. dodecandra medicinal specie, which contributes to the pharmacological and phytochemical background of C. dodecandra providing an added value to the traditional use of this specie.

Functional mechanism of tracheal relaxation, antiasthmatic, and toxicological studies of 6-hydroxyflavone.

Previously, we described tracheal rat rings relaxation by several flavonoids, being 6-hydroxyflavone (6-HOF) the most active derivative of the series. Thus, its mechanism of action was determined in an ex vivo tracheal rat ring bioassay. The anti-asthmatic effect was assayed in in vivo OVAlbumin (OVA)-sensitized guinea pigs. Finally, the toxicological profile of 6-HOF was studied based on Organization of Economic Cooperation and Development guidelines with modifications. 6-HOF-induced relaxation appears to be related with receptor-operated calcium channel and voltage-operated calcium channel blockade as the main mechanism of action, and also through the production of relaxant second messengers NO and cGMP. Molecular docking supports that 6-HOF acts as calcium channel blocker and by activation of nitric oxide synthase. In addition, the in vivo anti-asthmatic experiments demonstrate the dose-dependent significant anti-allergic effect of 6-HOF induced by OVA, with best activity at 50 /kg. Finally, toxicological studies determined a LD50 > 2,000 mg/kg and, after 28 day of treatment with 6-HOF (50 mg/kg) by intragastric route, mice did not exhibit evidence of any significant toxicity. In conclusion, experiments showed that 6-HOF exerts significant relaxant activity through calcium channel blockade, and possibly, by NO/cGMP-system stimulation on rat trachea, which interferes with the contraction mechanism of smooth muscle cells in the airways. In addition, the flavonoid shows potential anti-asthmatic properties in an anti-allergic pathway. Furthermore, because the pharmacological and safety evidence, we propose this flavonoid as lead for the development of a novel therapeutic agent for the treatment of asthma and related respiratory diseases.

1,8-Cineole blocks voltage-gated L-type calcium channels in tracheal smooth muscle.

1,8-Cineole is a cyclic monoterpenoid used in folk medicine for treatment of numerous respiratory diseases and other infections. 1,8-Cineole has anti-inflammatory, antioxidant, and myorelaxant effects, as well as low toxicity. In the present study, the effects of 1,8-cineole on contractility and voltage-gated calcium channels (VGCC) in tracheal smooth muscle were investigated. Intact and dissociated tracheal smooth muscle were used for muscle contraction and patch-clamp recordings, respectively. In experiments involving muscle contraction, 1,8-cineole potentiated contractions at low concentrations and relaxed contractions induced by isotonic K+ at high concentrations. AMTB (a TRPM8 channel blocker) reduced the potentiation induced by 1,8-cineole while indomethacin (a COX inhibitor) did not block this effect. In dissociated myocytes, 1,8-cineole partially blocked Ba2+ currents through VGCC in a concentration-dependent manner. 1,8-Cineole shifted the steady-state activation and inactivation curves to the left and also reduced the current decay time constant. In conclusion, 1,8-cineole has a dual effect on tracheal smooth muscle contraction resulting in a biphasic effect. Our data suggest that the potentiation effect is mediated by activation of TRPM8 channels and the relaxation effect is mediated by the blockage of L-type VGCC.

The Effects of Allium Cepa Extract on Tracheal Responsiveness, Lung Inflammatory Cells and Phospholipase A2 Level in Asthmatic Rats.

Antioxidant, antimicrobial, anti-hyperglycaemic, anti-diabetic and anti-inflammatory effects of Allium cepa (A. cepa) have been previously shown. In this study, the effects of A. cepa aqueous-alcoholic extract on tracheal responsiveness, lung inflammatory cells and phospholipase A2 (PLA2) level in bronchoalveolar fluid (BALF) of asthmatic rats were examined. Wistar rats were randomly divided into control group (C), asthmatic group (A), asthmatic group (A) treated with A. cepa extract (AC, 0.175, 0.35, and 0.7 mg/mL) and dexamethasone (D, 1.25 µg/mL). The extract of A. cepa and dexamethasone were added to animal's drinking water during sensitization period. Tracheal responsiveness to methacholine and ovalbumin, lung inflammatory cells and PLA2 level in BALF were assessed. Tracheal responsiveness to methacholine and ovalbumin, PLA2 level, total and most differential WBC count were increased but lymphocytes was decreased in asthmatic animals compared to group C (p<0.05 to p<0.001). Treatment of sensitized rats with dexamethasone and all concentrations of A. cepa lead to a significant decrease in total WBC and PLA2 level compared to asthmatic group (p<0.001). The two higher concentrations of A. cepa also significantly decreased tracheal responsiveness, neutrophil and eosinophil counts but led to a significant increase in lymphocytes count compared to asthmatic group (p<0.05 to p<0.001). Treatment of sensitized group with the highest concentration of A. cepa also significantly reduced monocyte count compared to asthmatic group (p<0.001). Anti-inflammatory and preventive effects of A. cepa on tracheal responsiveness and lung inflammation in asthmatic animals may suggest its potential therapeutic effect on airway diseases such as asthma.

Anti-allergy and anti-tussive activity of Clitoria ternatea L. in experimental animals.

ETHNOPHARMACOLOGICAL RELEVANCE: Clitoria ternatea flower is traditionally used in the treatment of respiratory disorders including bronchitis and is one of the ingredients in different Ayurvedic preparations that are used in respiratory disorders. However, till date there is no scientific report on the anti-asthmatic activity of this flower. AIM OF THE STUDY: Ethanolic extract of Clitoria ternatea flowers (ECT) was evaluated for its anti-allergy and anti-tussive potential in experimental animals. Additionally, the anti-inflammatory potential of ECT was carried out to draw a plausible mechanism of action of the drug. MATERIALS AND METHODS: In-vitro anti-asthmatic activity of ECT was evaluated in goat tracheal chain and isolated guinea pig ileum preparations. Acute and chronic anti-asthmatic activity of ECT (100, 200 and 400 mg/kg; p.o.) was estimated in histamine aerosol exposed guinea pigs and in OVA sensitized and challenged mice respectively. Anti-tussive activity of ECT (100, 200 and 400 mg/kg; p.o.) was evaluated against sulfur dioxide- and citric acid-induced cough in experimental animals. Moreover, the anti-inflammatory activity of ECT (100, 200 and 400 mg/kg; p.o.) was evaluated against carrageenan- and acetic acid-induced inflammation in rats. RESULTS: ECT attenuated histamine-induced contraction in both goat tracheal chain and isolated guinea pig ileum preparations. ECT (400 mg/kg) attenuated histamine-induced dyspnoea and OVA-induced changes in differential cell count in broncheoalveolar fluid, levels of interleukins (IL-1beta and IL-6) and immunoglobulin (OVA-sensitive IgG1) in animals. ECT (400 mg/kg) further ameliorated sulfur dioxide- and citric acid-induced cough in experimental animals. Additionally, ECT (400 mg/kg) attenuated inflammation in carrageenan and acetic acid challenged rodents. CONCLUSIONS: Standardized ECT could be considered as a potential therapeutic alternative in the management of allergy-induced asthma.

Muscarinic receptors, nitric oxide formation and cyclooxygenase pathway involved in tracheal smooth muscle relaxant effect of hydro-ethanolic extract of Lavandula angustifolia flowers.

BACKGROUND: Lavandula angustifolia (L. angustifolia) Mill. (Common name Lavender) is used in traditional and folk medicines for the treatment of various diseases including respiratory disorders worldwide. The relaxant effect of the plant on the smooth muscle of some tissues was shown previously. The present study has investigated the role of different receptors and pathways in the relaxant effect of L. angustifolia on tracheal smooth muscle. METHODS: Cumulative concentrations of the hydro-ethanolic extract of L. angustifolia flowers (0.5, 1, 2 and 4 mg/ml) were added on pre-contracted tracheal smooth muscle by methacholine (10 µM) or KCl (60 mM) on non-preincubated or preincubated tissues with atropine, chlorpheniramine, propranolol, diltiazem, glibenclamide, indomethacin, ω-nitro-L-arginine methyl ester (L-NAME) and papaverine. The results compared with of theophylline (0.2, 0.4, 0.6 and 0.8 mM) as positive control and saline (1 ml) as negative control. RESULTS: The extract showed concentration-dependent relaxant effects in non-preincubated tracheal smooth muscle contracted by KCl and methacholine (p < 0.05 to p < 0.001). The relaxant effect ofL. angustifolia was not significantly different between non-preincubated and preincubated tissues with chlorpheniramine, propranolol, diltiazem, glibenclamide, and papaverine. However, two higher concentrations of L. angustifolia in preincubated tissues with L-NAME (p < 0.01), indomethacin (p < 0.05 to p < 0.001) and atropine (p < 0.05) showed significantly lower relaxant effects than non-preincubated tissues. The EC50 values of L. angustifolia in tissues preincubated with indomethacin was significantly higher than non-preincubated trachea (p < 0.05). The effects of three first concentrations of the extract on KCl and methacholine-induced muscle contraction were significantly lower than those of theophylline (p < 0.05 to p < 0.001). CONCLUSIONS: These results indicated a relatively potent relaxant effect ofL. angustifolia that was lower than the effect of theophylline. The possible mechanisms of relaxant effect of this plant on tracheal smooth muscle are muscarinic receptors blockade, inhibition of cyclooxygenase pathways and/or involvement of nitric oxide production. Its clinical applications should be investigated in further studies.

Bronchodilator effects of Lignosus rhinocerotis extract on rat isolated airways is linked to the blockage of calcium entry.

BACKGROUND: Lignosus rhinocerotis (Cooke) Ryvarden is a popular medicinal mushroom used for centuries in Southeast Asia to treat asthma and chronic cough. The present study aimed to investigate the effect of this mushroom on airways patency. MATERIALS AND METHODS: The composition of L. rhinocerotis TM02 cultivar was analyzed. Organ bath experiment was employed to study the bronchodilator effect of Lignosus rhinocerotis cold water extract (CWE) on rat isolated airways. Trachea and bronchus were removed from male Sprague-Dawley rats, cut into rings of 2 mm, pre-contracted with carbachol before adding CWE into the bath in increasing concentrations. To investigate the influence of incubation time, tissues were exposed to intervals of 5, 15 and 30 min between CWE concentrations after pre-contraction with carbachol in subsequent protocol. Next, tissues were pre-incubated with CWE before the addition of different contractile agents, carbachol and 5-hydroxytrptamine (5-HT). The bronchodilator effect of CWE was compared with salmeterol and ipratropium. In order to uncover the mechanism of action of CWE, the role of beta-adrenoceptor, potassium and calcium channels was investigated. RESULTS: Composition analysis of TM02 cultivar revealed the presence of ß-glucans and derivatives of adenosine. The extract fully relaxed the trachea at 3.75 mg/ml (p < 0.0001) and bronchus at 2.5 mg/ml (p < 0.0001). It was observed that lower concentrations of CWE were able to fully relax both trachea and bronchus but at a longer incubation interval between concentrations. CWE pre-incubation significantly reduced the maximum responses of carbachol-induced contractions (in both trachea, p = 0.0012 and bronchus, p = 0.001), and 5-HT-induced contractions (in trachea, p = 0.0048 and bronchus, p = 0.0014). Ipratropium has demonstrated a significant relaxation effect in both trachea (p = 0.0004) and bronchus (p = 0.0031), whereas salmeterol has only affected the bronchus (p = 0.0104). The involvement of ß2-adrenoceptor and potassium channel in CWE-mediated airway relaxation is ruled out, but the bronchodilator effect was unequivocally affected by influx of calcium. CONCLUSIONS: The bronchodilator effect of L. rhinocerotis on airways is mediated by calcium signalling pathway downstream of Gαq-coupled protein receptors. The airway relaxation effect is both concentration- and incubation time-dependent. Our findings provide unequivocal evidence to support its traditional use to relieve asthma and cough.

A micro-scale printable nanoclip for electrical stimulation and recording in small nerves.

OBJECTIVE: The vision of bioelectronic medicine is to treat disease by modulating the signaling of visceral nerves near various end organs. In small animal models, the nerves of interest can have small diameters and limited surgical access. New high-resolution methods for building nerve interfaces are desirable. In this study, we present a novel nerve interface and demonstrate its use for stimulation and recording in small nerves. APPROACH: We design and fabricate micro-scale electrode-laden nanoclips capable of interfacing with nerves as small as 50 µm in diameter. The nanoclips are fabricated using a direct laser writing technique with a resolution of 200 nm. The resolution of the printing process allows for incorporation of a number of innovations such as trapdoors to secure the device to the nerve, and quick-release mounts that facilitate keyhole surgery, obviating the need for forceps. The nanoclip can be built around various electrode materials; here we use carbon nanotube fibers for minimally invasive tethering. MAIN RESULTS: We present data from stimulation-evoked responses of the tracheal syringeal (hypoglossal) nerve of the zebra finch, as well as quantification of nerve functionality at various time points post implant, demonstrating that the nanoclip is compatible with healthy nerve activity over sub-chronic timescales. SIGNIFICANCE: Our nerve interface addresses key challenges in interfacing with small nerves in the peripheral nervous system. Its small size, ability to remain on the nerve over sub-chronic timescales, and ease of implantation, make it a promising tool for future use in the treatment of disease.

Nelumbo nucifera leaves extracts inhibit mouse airway smooth muscle contraction.

BACKGROUND: Alkaloids extracted from lotus leaves (AELL) can relax vascular smooth muscle. However, whether AELL has a similar relaxant role on airway smooth muscle (ASM) remains unknown. This study aimed to explore the relaxant property of AELL on ASM and the underlying mechanism. METHODS: Alkaloids were extracted from dried lotus leaves using the high temperature rotary evaporation extraction method. The effects of AELL on mouse ASM tension were studied using force measuring and patch-clamp techniques. RESULTS: It was found that AELL inhibited the high K+ or acetylcholine chloride (ACh)-induced precontraction of mouse tracheal rings by 64.8 ± 2.9%, or 48.8 ± 4.7%, respectively. The inhibition was statistically significant and performed in a dose-dependent manner. Furthermore, AELL-induced smooth muscle relaxation was partially mediated by blocking voltage-dependent Ca2+ channels (VDCC) and non-selective cation channels (NSCC). CONCLUSION: AELL, which plays a relaxant role in ASM, might be a new complementary treatment to treat abnormal contractions of the trachea and asthma.

A mechanistic evaluation of the traditional uses of Nepeta ruderalis in gastrointestinal and airway disorders.

CONTEXT: Nepeta ruderalis Buch.-Ham. (Lamiaceae), locally known as Badranj Boya, is an aromatic herb used traditionally as an antispasmodic, antidiarrhoeal, and anti-asthamatic remedy. OBJECTIVE: Aqueous methanolic extract of N. ruderalis was studied to investigate its traditional uses. MATERIALS AND METHODS: Study was conducted from September 2015 to February 2016. In vitro spasmolytic and broncho-relaxant activity of crude extract of N. ruderalis (whole plant) was evaluated at 0.01-10 mg/mL final bath concentration in isolated rabbit jejunum and tracheal tissues, using PowerLab data acquisition system (Transonic Systems Inc., Ithaca, NY). In vivo antidiarrhoeal activity was evaluated in castor oil-induced diarrhoeal mice at the dose of 300 and 500 mg of crude extract orally. RESULTS: Crude extract of N. ruderalis completely relaxed spontaneously contracting, high K+ (80 mM) and carbachol (1 µM) induced contracted jejunum with an EC50 value of 5.85 (5.45-6.27), 4.0 (3.80-4.23) and 2.86 (2.48-3.29), similar to verapamil. Nr.Cr relaxed high K+ and carbachol induced contractions, at 5 and 10 mg/mL with an EC50 value of 2.37 (2.11-2.67) and 3.26 (2.9-3.67), respectively, and also displaced calcium concentration-response curves toward right at 0.1 and 0.3 mg/mL. Nr.Cr exhibited antidiarrhoeal protection at a dose of 300 and 500 mg/kg, similar to verapamil, whereas no acute toxicity signs were seen up to 5 g/kg in healthy mice. DISCUSSION AND CONCLUSION: Results suggest the presence of spasmolytic and broncho-relaxant effects in the crude extract of N. ruderalis, possibly mediated through calcium channel-blocking activity, providing the pharmacological basis for its traditional uses in gastrointestinal and airway disorders.

Effects of magnesium sulfate on airway smooth muscle contraction in rats.

Aim To investigate the effect of magnesium sulfate (MgSO4) at different doses on isolated tracheal smooth muscle contraction in rats induced by different mechanisms. Methods Twelve rats' tracheas were placed into organ bath. Consecutively, acetylcholine (10-6,10-5,10-4 M), histamine(10-8,10-5,10-3 M) and KCl (30,60 mM) solutions was administered for contractions. MgSO4 from 10-4 to 10-1 M concentrations were subsequently administered after each constrictive agent and relaxation degrees were recorded. Results In the acetylcholine and KCl groups, dose dependent strong contractions were observed, but not in the histamine group and that group was excluded. Significant relaxation occurred with gradually increasing doses of MgSO4. In the high dose KCl group, a slight increase in contractions after the administration of 10-4 and 10-3 M MgSO4 was recorded. Conclusion We suggest that MgSO4 is effective in relaxing airway smooth muscle contractions caused by different factors; however, it must be considered that low doses of MgSO4 may only lead to a slight increase in contractions.