&lt;em&gt;In vitro&lt;/em&gt; Measurements of Tracheal Constriction Using Mice

Semenov, Iurii; Herlihy, Jeremiah T.; Brenner, Robert

doi:10.3791/3703

Cited by 13 publications

(12 citation statements)

References 31 publications

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“…Control animals used in these studies were 2–3 month old C57BL/6J mice strain from Jackson Labs, or 2–3 week old rats (Sprague Dawley) from Charles River Labs. For tracheal constriction studies we used previously published protocols (Semenov et al, 2012). Animals were deeply anesthetized with isoflurane and then sacrificed by cervical dislocation.…”

Section: Methodsmentioning

confidence: 99%

Functional effects of KCNQ K+ channels in airway smooth muscle

et al. 2013

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KCNQ (Kv7) channels underlie a voltage-gated K+ current best known for control of neuronal excitability, and its inhibition by Gq/11-coupled, muscarinic signaling. Studies have indicated expression of KCNQ channels in airway smooth muscle (ASM), a tissue that is predominantly regulated by muscarinic receptor signaling. Therefore, we investigated the function of KCNQ channels in rodent ASM and their interplay with Gq/11-coupled M3 muscarinic receptors. Perforated-patch clamp of dissociated ASM cells detected a K+ current inhibited by the KCNQ antagonist, XE991, and augmented by the specific agonist, flupirtine. KCNQ channels begin to activate at voltages near resting potentials for ASM cells, and indeed XE991 depolarized resting membrane potentials. Muscarinic receptor activation inhibited KCNQ current weakly (~20%) at concentrations half-maximal for contractions. Thus, we were surprised to see that KCNQ had no affect on membrane voltage or muscle contractility following muscarinic activation. Further, M3 receptor-specific antagonist J104129 fumarate alone did not reveal KCNQ effects on muscarinic evoked depolarization or contractility. However, a role for KCNQ channels was revealed when BK-K+ channel activities are reduced. While KCNQ channels do control resting potentials, they appear to play a redundant role with BK calcium-activated K+ channels during ASM muscarinic signaling. In contrast to effect of antagonist, we observe that KCNQ agonist flupirtine caused a significant hyperpolarization and reduced contraction in vitro irrespective of muscarinic activation. Using non-invasive whole animal plethysmography, the clinically approved KCNQ agonist retigabine caused a transient reduction in indexes of airway resistance in both wild type and BK β1 knockout (KO) mice treated with the muscarinic agonist. These findings indicate that KCNQ channels can be recruited via agonists to oppose muscarinic evoked contractions and may be of therapeutic value as bronchodilators.

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Section: Methodsmentioning

confidence: 99%

Functional effects of KCNQ K+ channels in airway smooth muscle

et al. 2013

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“…; Semenov et al. ). It was generally assumed that high K + solution mediates contraction through smooth muscle depolarization and activation of voltage‐gated calcium channels.…”

Section: Discussionmentioning

confidence: 97%

Voltage effects on muscarinic acetylcholine receptor‐mediated contractions of airway smooth muscle

Semenov

Brenner

2018

Physiol Rep

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Studies have shown that the activity of muscarinic receptors and their affinity to agonists are sensitive to membrane potential. It was reported that in airway smooth muscle (ASM) depolarization evoked by high K+ solution increases contractility through direct effects on M3 muscarinic receptors. In this study, we assessed the physiological relevance of voltage sensitivity of muscarinic receptors on ASM contractility. Our findings reveal that depolarization by high K+ solution induces contraction in intact mouse trachea predominantly through activation of acetylcholine release from embedded nerves, and to a lesser extent by direct effects on M3 receptors. We therefore devised a pharmacological approach to depolarize tissue to various extents in an organ bath preparation, and isolate contraction due exclusively to ASM muscarinic receptors within range of physiological voltages. Our results indicate that unliganded muscarinic receptors do not contribute to contraction regardless of voltage. Utilizing low K+ solution to hyperpolarize membrane potentials during contractions had no effect on liganded muscarinic receptor‐evoked contractions, although it eliminated the contribution of voltage‐gated calcium channels. However, we found that muscarinic signaling was potentiated by at least 42% at depolarizing voltages (average −12 mV) induced by high K+ solution (20 mmol/L K+). In summary, we conclude that contractions evoked by direct activation of muscarinic receptors have negligible sensitivity to physiological voltages. However, contraction activated by cholinergic stimulation can be potentiated by membrane potentials occurring beyond the physiological range of ASM.

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“…ACh administrations have increased tracheal smooth muscle contraction through ACh-M 3 receptor stimulation [25][26][27]. ACh-M 3 receptors expressed in various types of cells and this receptor cellular signal is mediated by ACh.…”

Section: Discussionmentioning

confidence: 99%

“…MLCK activation results are cross-linking between actin and myosin. The bond formation between myosin and actin and this may lead to contraction of the smooth muscle [26,29].…”

Section: Discussionmentioning

confidence: 99%

Inhibitory Effect of Ethanolic Extract of Curanga Fel-Terrae (Pugun Tano) Leaves on Acetylcholine Muscarinic-3 Receptors Induced on Isolated Guinea Pig Tracheal

Husori

Harahap²,

Nil³

et al. 2016

Asian J Pharm Clin Res

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Objective: The study was aimed to investigate the inhibitory effect of ethanolic extract of Curanga fel-terrae leaves (EECFL) against acetylcholine (ACh)-induced contraction of the ACh-muscarinic-3 receptor. Materials and Methods:The study of the inhibitory effect of the ethanolic extract on the contraction by ACh concentration series (10 −8 -10 −3 M) was conducted in vitro using isolated guinea pig tracheal organ in the Krebs solution.Results: Early incubation of tracheal organ with EECFL (0.5, 1, 2 and 4 mg/ml) before contracted by the series of ACh concentration produces the decrease of ACh contraction. The concentration series of ACh sigmoid curve rightward shift without decreasing the maximal contraction. The results of double-reciprocal plot of ACh shows the mean value of the 1/y-intercept of each extract was not different with the control. Conclusion:The EECFL showed competitive antagonist effect on ACh-muscarinic-3 receptors.

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<em>In vitro</em> Measurements of Tracheal Constriction Using Mice

Cited by 13 publications

References 31 publications

Functional effects of KCNQ K+ channels in airway smooth muscle

Functional effects of KCNQ K+ channels in airway smooth muscle

Voltage effects on muscarinic acetylcholine receptor‐mediated contractions of airway smooth muscle

Inhibitory Effect of Ethanolic Extract of Curanga Fel-Terrae (Pugun Tano) Leaves on Acetylcholine Muscarinic-3 Receptors Induced on Isolated Guinea Pig Tracheal

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