scholarly journals Substance P is essential for maintaining gut muscle contractility: a novel role for coneurotransmission revealed by botulinum toxin

2014 ◽  
Vol 306 (10) ◽  
pp. G839-G848 ◽  
Author(s):  
Cuiping Li ◽  
Maria-Adelaide Micci ◽  
Karnam S. Murthy ◽  
Pankaj Jay Pasricha
Keyword(s):  
Smooth Muscle ◽  
Botulinum Toxin ◽  
Substance P ◽  
Motor Neurons ◽  
Ex Vivo ◽  
Organ Bath ◽  
Excitatory Neurotransmitter ◽  
Vesicular Release ◽  
Nk1 Receptor Antagonist ◽  
Pyloric Muscle

Substance P (SP) is commonly coexpressed with ACh in enteric motor neurons, and, according to the classical paradigm, both these neurotransmitters excite smooth muscle via parallel pathways. We hypothesized that, in addition, SP was responsible for maintaining the muscular responsiveness to ACh. We tested this hypothesis by using botulinum toxin (BoNT/A), a known blocker of vesicular release of neurotransmitters including ACh and neuropeptides. BoNT/A was injected into rat pyloric sphincter in different doses; as control we used boiled BoNT/A. At the desired time point, pylorus was dissected out and pyloric contractility was measured ex vivo in an organ bath and by measuring phosphorylation of myosin light chain 20 (MLC20). BoNT/A (10 IU) significantly reduced the response of pyloric muscle to exogenous ACh, an effect that was accompanied by reduced MLC20 phosphorylation in the muscle. Both effects were reversed by exogenous SP. CP-96345, a NK1 receptor antagonist, blocked the ability of exogenous SP to reverse the cholinergic hyporesponsiveness as well as the reduction in MLC20 phosphorylation induced by BoNT/A. In conclusion, we have identified a novel role for SP as a coneurotransmitter that appears to be important for the maintenance of muscular responsiveness to the principal excitatory neurotransmitter, ACh. These results also provide new insight into the effects of botulinum toxin on the enteric nervous system and gastrointestinal smooth muscle.

N-Acetylcysteine Does Not Improve the Endothelial and Smooth Muscle Function in the Human Saphenous Vein

2007 ◽  
Vol 41 (3) ◽  
pp. 239-245 ◽  
Author(s):  
Muhammad Anees Sharif ◽  
Ulvi Bayraktutan ◽  
Ian Stuart Young ◽  
Chee Voon Soong
Keyword(s):  
Smooth Muscle ◽  
Saphenous Vein ◽  
Muscle Function ◽  
Ex Vivo ◽  
Smooth Muscle Relaxation ◽  
Organ Bath ◽  
Human Saphenous Vein ◽  
Vein Segment ◽  
Significant Difference ◽  
Smooth Muscle Function

Oxidative stress can lead to vein graft dysfunction in the saphenous vein. This ex vivo study is aimed to compare the effects of increasing concentrations of the antioxidant N-acetylcysteine (NAC) with heparinized saline (HS) on endothelial and smooth muscle function in the human saphenous vein. Long saphenous vein segment obtained during infrainguinal bypass surgery was divided into 7 rings; 1 immersed in HS and the remaining 6 in increasing NAC concentrations (0.0025%, 0.005%, 0.01%, 0.02%, 0.03%, and 0.04%). Rings were mounted in an organ bath, and relaxant responses to acetylcholine and sodium nitroprusside were assessed through isometric tension studies. Endothelium-dependent relaxations were observed in 77 vein segments from 11 patients. No significant difference was seen in veins treated with either lower NAC concentrations (0.0025%, 0.005%, 0.01%, 0.02%, and 0.03%) or HS. However, HS-treated veins showed significantly better relaxation compared to those treated with maximum (0.04%) NAC ( P < .05). Endothelium-independent relaxations were observed in 91 segments from 13 patients. No difference in relaxation was observed between veins treated with HS or any of the NAC concentrations. In conclusion, lower NAC concentrations do not offer better endothelial protection than HS, whereas the highest NAC concentration has a detrimental effect on endothelium-dependent relaxation. Moreover, NAC did not show beneficial effect on direct smooth muscle relaxation.

scholarly journals A novel GABAA receptor ligand MIDD0301 with limited blood-brain barrier penetration relaxes airway smooth muscle ex vivo and in vivo

2019 ◽  
Vol 316 (2) ◽  
pp. L385-L390 ◽  
Author(s):  
Gene T. Yocum ◽  
Jose F. Perez-Zoghbi ◽  
Jennifer Danielsson ◽  
Aisha S. Kuforiji ◽  
Yi Zhang ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Ex Vivo ◽  
Drug Candidate ◽  
Organ Bath ◽  
Forced Oscillation Technique ◽  
Gaba A ◽  
Peripheral Airways ◽  
Trace Concentrations

Airway smooth muscle (ASM) cells express GABA A receptors (GABAARs), and previous reports have demonstrated that GABAAR activators relax ASM. However, given the activity of GABAARs in central nervous system inhibitory neurotransmission, concern exists that these activators may lead to undesirable sedation. MIDD0301 is a novel imidazobenzodiazepine and positive allosteric modulator of the GABAAR with limited brain distribution, thus eliminating the potential for sedation. Here, we demonstrate that MIDD0301 relaxes histamine-contracted guinea pig ( P < 0.05, n = 6–9) and human ( P < 0.05, n = 6–10) tracheal smooth muscle ex vivo in organ bath experiments, dilates mouse peripheral airways ex vivo in precision-cut lung-slice experiments ( P < 0.001, n = 16 airways from three mice), and alleviates bronchoconstriction in vivo in mice, as assessed by the forced-oscillation technique ( P < 0.05, n = 6 mice). Only trace concentrations of the compound were detected in the brains of mice after inhalation of nebulized 5 mM MIDD0301. Given its favorable pharmacokinetic properties and demonstrated ability to relax ASM in a number of clinically relevant experimental paradigms, MIDD0301 is a promising drug candidate for bronchoconstrictive diseases, such as asthma.

scholarly journals The Inhibitory Effect of Botulinum Toxin Type A on Rat Pyloric Smooth Muscle Contractile Response to Substance P In Vitro

Toxins ◽  
2015 ◽  
Vol 7 (10) ◽  
pp. 4143-4156 ◽  
Author(s):  
Yu-Feng Shao ◽  
Jun-Fan Xie ◽  
Yin-Xiang Ren ◽  
Can Wang ◽  
Xiang-Pan Kong ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Botulinum Toxin ◽  
Substance P ◽  
Contractile Response ◽  
Botulinum Toxin Type A ◽  
Type A ◽  
Botulinum Toxin Type ◽  
Inhibitory Effect ◽  
Muscle Contractile

scholarly journals Agonism of the TMEM16A calcium-activated chloride channel modulates airway smooth muscle tone

2020 ◽  
Vol 318 (2) ◽  
pp. L287-L295 ◽  
Author(s):  
Jennifer Danielsson ◽  
Aisha S. Kuforiji ◽  
Gene T. Yocum ◽  
Yi Zhang ◽  
Dingbang Xu ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Chloride Channel ◽  
Airway Resistance ◽  
Muscle Tone ◽  
Ex Vivo ◽  
Organ Bath ◽  
Novel Therapies ◽  
In Vivo Models

TMEM16A (anoctamin 1) is an important calcium-activated chloride channel in airway smooth muscle (ASM). We have previously shown that TMEM16A antagonists such as benzbromarone relax ASM and have proposed TMEM16A antagonists as novel therapies for asthma treatment. However, TMEM16A is also expressed on airway epithelium, and TMEM16A agonists are being investigated as novel therapies for cystic fibrosis. There are theoretical concerns that agonism of TMEM16A on ASM could lead to bronchospasm, making them detrimental as airway therapeutics. The TMEM16A agonist Eact induced a significant contraction of human ASM and guinea pig tracheal rings in an ex vivo organ bath model. Pretreatment with two different TMEM16A antagonists, benzbromarone or T16Ainh-A01, completely attenuated these Eact-induced contractions. Pretreatment with Eact alone augmented the maximum acetylcholine contraction. Pretreatment of A/J mice in vivo with nebulized Eact caused an augmentation of methacholine-induced increases in airway resistance measured by the forced oscillatory technique (flexiVent). Pretreatment with the TMEM16A antagonist benzbromarone significantly attenuated methacholine-induced increases in airway resistance. In in vitro cellular studies, TMEM16A was found to be expressed more abundantly in ASM compared with epithelial cells in culture (8-fold higher in ASM). Eact caused an increase in intracellular calcium in human ASM cells that was completely attenuated by pretreatment with benzbromarone. Eact acutely depolarized the plasma membrane potential of ASM cells, which was attenuated by benzbromarone or nifedipine. The TMEM16A agonist Eact modulates ASM contraction in both ex vivo and in vivo models, suggesting that agonism of TMEM16A may lead to clinically relevant bronchospasm.

Tachykinins as transmitters of ascending contractile component of the peristaltic reflex

1989 ◽  
Vol 257 (5) ◽  
pp. G709-G714 ◽  
Author(s):  
J. R. Grider
Keyword(s):  
Smooth Muscle ◽  
Substance P ◽  
Smooth Muscle Cells ◽  
Motor Neurons ◽  
Myenteric Plexus ◽  
Peristaltic Reflex ◽  
Release Of Acetylcholine ◽  
Substance K ◽  
Separate Measurement

The role of tachykinin neurons of the myenteric plexus in the regulation of the intestinal peristaltic reflex was examined in rat colonic segments that enable separate measurement of ascending contraction and descending relaxation. Release of immunoreactive substance P (SP) and substance K (SK) increased (68% for SP; 70% for SK) during ascending contraction and decreased (37% for SP; 13% for SK) during descending relaxation. Exogenous SP and SK augmented ascending contraction and inhibited descending relaxation. Neither SP antiserum nor SK antiserum had any effect on descending relaxation. The antisera had no effect also on ascending contraction induced by low grades of stretch (2 g), but they inhibited significantly contraction induced by high grades (6-10 g) of stretch (52 +/- 8% inhibition with SP antiserum and 48 +/- 8% with SK antiserum). A combination of both antisera abolished ascending contraction induced by high grades of stretch. Atropine inhibited only partially ascending contraction at high grades of stretch. The pattern of inhibition by both antisera and by atropine implied that ascending contraction induced by high grades of stretch was mediated by tachykinin neurons acting directly on smooth muscle cells as well as indirectly via release of acetylcholine from cholinergic motor neurons.

scholarly journals Constitutively active PKA regulates neuronal acetylcholine release and contractility of guinea pig urinary bladder smooth muscle

2016 ◽  
Vol 310 (11) ◽  
pp. F1377-F1384 ◽  
Author(s):  
Wenkuan Xin ◽  
Ning Li ◽  
Vitor S. Fernandes ◽  
Georgi V. Petkov
Keyword(s):  
Smooth Muscle ◽  
Urinary Bladder ◽  
Guinea Pig ◽  
Motor Neurons ◽  
Acetylcholinesterase Inhibitor ◽  
Colorimetric Method ◽  
Bladder Smooth Muscle ◽  
Ach Release ◽  
Excitatory Neurotransmitter ◽  
Constitutively Active

Autonomic and somatic motor neurons that innervate the urinary bladder and urethra control the highly coordinated functions of the lower urinary tract, the storage, and the emptying of urine. ACh is the primary excitatory neurotransmitter in the bladder. Here, we aimed to determine whether PKA regulates neuronal ACh release and related nerve-evoked detrusor smooth muscle (DSM) contractions in the guinea pig urinary bladder. Isometric DSM tension recordings were used to measure spontaneous phasic and electrical field stimulation (EFS)- and carbachol-induced DSM contractions with a combination of pharmacological tools. The colorimetric method was used to measure ACh released by the parasympathetic nerves in DSM isolated strips. The pharmacological inhibition of PKA with H-89 (10 μM) increased the spontaneous phasic contractions, whereas it attenuated the EFS-induced DSM contractions. Intriguingly, H-89 (10 μM) attenuated the (primary) cholinergic component, whereas it simultaneously increased the (secondary) purinergic component of the nerve-evoked contractions in DSM isolated strips. The acetylcholinesterase inhibitor, eserine (10 μM), increased EFS-induced DSM contractions, and the subsequent addition of H-89 attenuated the contractions. H-89 (10 μM) significantly increased DSM phasic contractions induced by the cholinergic agonist carbachol. The inhibition of PKA decreased the neuronal release of ACh in DSM tissues. This study revealed that PKA-mediated signaling pathways differentially regulate nerve-evoked and spontaneous phasic contractions of guinea pig DSM. Constitutively active PKA in the bladder nerves controls synaptic ACh release, thus regulating the nerve-evoked DSM contractions, whereas PKA in DSM cells controls the spontaneous phasic contractility.

Differential Ca2+ signaling characteristics of inhibitory and excitatory myenteric motor neurons in culture

2000 ◽  
Vol 279 (5) ◽  
pp. G1121-G1127 ◽  
Author(s):  
Pieter Vanden Berghe ◽  
Sander Molhoek ◽  
Ludwig Missiaen ◽  
Jan Tack ◽  
Jozef Janssens
Keyword(s):  
Substance P ◽  
Motor Neurons ◽  
Circular Muscle ◽  
Receptor Expression ◽  
Inhibitory Neurons ◽  
Excitatory Neurotransmitter ◽  
Retrograde Labeling ◽  
Transient Rise ◽  
Excitatory Neurotransmitters ◽  
Intracellular Ca

Physiological studies on functionally identified myenteric neurons are scarce because of technical limitations. We combined retrograde labeling, cell culturing, and fluorescent intracellular Ca2+ concentration ([Ca2+]i) signaling to study excitatory neurotransmitter responsiveness of myenteric motor neurons. 1,1-Didodecyl-3,3,3′,3′-tetramethyl indocarbocyanine (DiI) was used to label circular muscle motor neurons of the guinea pig ileum. DiI-labeled neurons were easily detectable in cultures prepared from these segments. The excitatory neurotransmitters (10−5 M) acetylcholine, substance P, and serotonin induced a transient rise in [Ca2+]i in subsets of DiI-labeled neurons (66.7, 56.5, and 84.3%, respectively). DiI-labeled motor neurons were either inhibitory (23.8%) or excitatory (76.2%) as assessed by staining for nitric oxide synthase or choline acetyltransferase. Compared with excitatory motor neurons, significantly fewer inhibitory neurons in culture responded to acetylcholine (0 vs. 69%) and substance P (12.5 vs. 69.2%). We conclude that combining retrograde labeling and Ca2+ imaging allows identification of differential receptor expression in functionally identified neurons in culture.

scholarly journals Combination of histochemical analyses and micro-MRI reveals regional changes of the murine cervix in preparation for labor

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Antara Chatterjee ◽  
Rojan Saghian ◽  
Anna Dorogin ◽  
Lindsay S. Cahill ◽  
John G. Sled ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Diffusion Tensor ◽  
Ex Vivo ◽  
Muscle Cells ◽  
Pregnant Mouse ◽  
Collagen Fibers ◽  
Muscular Layer ◽  
Tissue Organization ◽  
Picrosirius Red

AbstractThe cervix is responsible for maintaining pregnancy, and its timely remodeling is essential for the proper delivery of a baby. Cervical insufficiency, or “weakness”, may lead to preterm birth, which causes infant morbidities and mortalities worldwide. We used a mouse model of pregnancy and term labor, to examine the cervical structure by histology (Masson Trichome and Picrosirius Red staining), immunohistochemistry (Hyaluronic Acid Binding Protein/HABP), and ex-vivo MRI (T2-weighted and diffusion tensor imaging), focusing on two regions of the cervix (i.e., endocervix and ectocervix). Our results show that mouse endocervix has a higher proportion of smooth muscle cells and collagen fibers per area, with more compact tissue structure, than the ectocervix. With advanced gestation, endocervical changes, indicative of impending delivery, are manifested in fewer smooth muscle cells, expansion of the extracellular space, and lower presence of collagen fibers. MRI detected three distinctive zones in pregnant mouse endocervix: (1) inner collagenous layer, (2) middle circular muscular layer, and (3) outer longitudinal muscular layer. Diffusion MRI images detected changes in tissue organization as gestation progressed suggesting the potential application of this technique to non-invasively monitor cervical changes that precede the onset of labor in women at risk for preterm delivery.

scholarly journals NTPDase1 Modulates Smooth Muscle Contraction in Mice Bladder by Regulating Nucleotide Receptor Activation Distinctly in Male and Female

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 147
Author(s):  
Romuald Brice Babou Kammoe ◽  
Gilles Kauffenstein ◽  
Julie Pelletier ◽  
Bernard Robaye ◽  
Jean Sévigny
Keyword(s):  
Smooth Muscle ◽  
Ex Vivo ◽  
Smooth Muscle Contraction ◽  
Receptor Activation ◽  
Nucleoside Triphosphate ◽  
Nucleotide Receptors ◽  
Nerve Terminals ◽  
Wild Type ◽  
Nucleoside Triphosphate Diphosphohydrolase ◽  
Bladder Contraction

Nucleotides released by smooth muscle cells (SMCs) and by innervating nerve terminals activate specific P2 receptors and modulate bladder contraction. We hypothesized that cell surface enzymes regulate SMC contraction in mice bladder by controlling the concentration of nucleotides. We showed by immunohistochemistry, enzymatic histochemistry, and biochemical activities that nucleoside triphosphate diphosphohydrolase-1 (NTPDase1) and ecto-5′-nucleotidase were the major ectonucleotidases expressed by SMCs in the bladder. RT-qPCR revealed that, among the nucleotide receptors, there was higher expression of P2X1, P2Y1, and P2Y6 receptors. Ex vivo, nucleotides induced a more potent contraction of bladder strips isolated from NTPDase1 deficient (Entpd1−/−) mice compared to wild type controls. The strongest responses were obtained with uridine 5′-triphosphate (UTP) and uridine 5′-diphosphate (UDP), suggesting the involvement of P2Y6 receptors, which was confirmed with P2ry6−/− bladder strips. Interestingly, this response was reduced in female bladders. Our results also suggest the participation of P2X1, P2Y2 and/or P2Y4, and P2Y12 in these contractions. A reduced response to the thromboxane analogue U46619 was also observed in wild type, Entpd1−/−, and P2ry6−/− female bladders showing another difference due to sex. In summary, NTPDase1 modulates the activation of nucleotide receptors in mouse bladder SMCs, and contractions induced by P2Y6 receptor activation were weaker in female bladders.

Myometrial Responses to Beta-Adrenoceptor Antagonists in Gynecological Malignancies

2021 ◽  
pp. 1-8
Author(s):  
Beata Modzelewska ◽  
Marcin Jóźwik ◽  
Tomasz Kleszczewski ◽  
Stanisław Sulkowski ◽  
Maciej Jóźwik
Keyword(s):  
Ovarian Cancer ◽  
Cervical Cancer ◽  
Reference Group ◽  
Ex Vivo ◽  
Contractile Activity ◽  
Organ Bath ◽  
Human Uterus ◽  
Uterine Contractility ◽  
Beta Adrenoceptor ◽  
Gynecological Malignancies

Objective: The aim of the study was to determine the influence of beta-adrenoceptor (ADRB) antagonists on contractile activity of the nonpregnant human uterus in patients affected by gynecological malignancies. Design: This was a controlled and prospective ex vivo study. Setting: The work was conducted as a collaboration between 4 academic departments. Materials and Methods: Myometrial specimens were obtained from women undergoing hysterectomy for benign gynecological disorders (reference group; N = 15), and ovarian (N = 15), endometrial (N = 15), synchronous ovarian-endometrial (N = 3), and cervical cancer (N = 10). Contractions of myometrial strips in an organ bath before and after applications of ADRB antagonists (propranolol, bupranolol, SR 59230A, and butoxamine) were studied under isometric conditions. Results: Propranolol and bupranolol attenuated contractions in the endometrial and cervical cancer groups similar to that in the reference group (all p < 0.05), whereas opposite effects were observed in the ovarian and synchronous ovarian-endometrial cancer groups. SR 59230A and butoxamine significantly increased contractions in the ovarian cancer group (both p < 0.001). Limitations: These results require now to be placed into a firm clinical context. Conclusions: Our study indicates that ovarian cancer considerably alters contractile activity of the nonpregnant human uterus in response to ADRB antagonists. This suggests a pathogenetic role of beta-adrenergic pathways in this malignancy. Furthermore, propranolol and bupranolol substantially influence spontaneous uterine contractility.

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