Functional coupling between the Na+/Ca2+ exchanger and nonselective cation channels during histamine stimulation in guinea pig tracheal smooth muscle

2007 ◽  
Vol 293 (1) ◽  
pp. L191-L198 ◽  
Author(s):  
Paola Algara-Suárez ◽  
Catalina Romero-Méndez ◽  
Tom Chrones ◽  
Sergio Sánchez-Armass ◽  
Ulises Meza ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Force Measurement ◽  
Isometric Force ◽  
Sustained Response ◽  
Functional Coupling ◽  
Channel Activation ◽  
Histamine Stimulation ◽  
Nonselective Cation Channels ◽  
Intracellular Ca

Airway smooth muscle (ASM) contracts partly due to an increase in cytosolic Ca2+. In this work, we found that the contraction caused by histamine depends on external Na+, possibly involving nonselective cationic channels (NSCC) and the Na+/Ca2+ exchanger (NCX). We performed various protocols using isometric force measurement of guinea pig tracheal rings stimulated by histamine. We observed that force reached 53 ± 1% of control during external Na+ substitution by N-methyl-d-glucamine+, whereas substitution by Li+ led to no significant change (91 ± 1%). Preincubation with KB-R7943 decreased the maximal force developed (52.3 ± 5.6%), whereas preincubation with nifedipine did not (89.7 ± 1.8%). Also, application of the nonspecific NCX blocker KB-R7943 and nifedipine on histamine-precontracted tracheal rings reduced force to 1 ± 3%, significantly different from nifedipine alone (49 ± 6%). Moreover, nonspecific NSCC inhibitors SKF-96365 and 2-aminoethyldiphenyl borate reduced force to 1 ± 1% and 19 ± 7%, respectively. Intracellular Ca2+ measurements in isolated ASM cells showed that KB-R7943 and SKF-96365 reduced the peak and sustained response to histamine (0.20 ± 0.1 and 0.19 ± 0.09 for KB-R, 0.43 ± 0.16 and 0.47 ± 0.18 for SKF, expressed as mean of differences). Moreover, Na+-free solution only inhibited the sustained response (0.54 ± 0.25). These data support an important role for NSCC and NCX during histamine stimulation. We speculate that histamine induces Na+ influx through NSCC that promotes the Ca2+ entry mode of NCX and CaV1.2 channel activation, thereby causing contraction.

Effect of airway inflammation on smooth muscle shortening and contractility in guinea pig trachealis

1993 ◽  
Vol 265 (6) ◽  
pp. L549-L554 ◽  
Author(s):  
R. W. Mitchell ◽  
I. M. Ndukwu ◽  
K. Arbetter ◽  
J. Solway ◽  
A. R. Leff
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Neurogenic Inflammation ◽  
Isometric Force ◽  
Electrical Field Stimulation ◽  
Shortening Velocity ◽  
Lever System ◽  
Force Velocity

We studied the effect of either 1) immunogenic inflammation caused by aerosolized ovalbumin or 2) neurogenic inflammation caused by aerosolized capsaicin in vivo on guinea pig tracheal smooth muscle (TSM) contractility in vitro. Force-velocity relationships were determined for nine epithelium-intact TSM strips from ovalbumin-sensitized (OAS) vs. seven sham-sensitized controls and TSM strips for seven animals treated with capsaicin aerosol (Cap-Aer) vs. eight sham controls. Muscle strips were tethered to an electromagnetic lever system, which allowed isotonic shortening when load clamps [from 0 to maximal isometric force (Po)] were applied at specific times after onset of contraction. Contractions were elicited by supramaximal electrical field stimulation (60 Hz, 10-s duration, 18 V). Optimal length for each muscle was determined during equilibration. Maximal shortening velocity (Vmax) was increased in TSM from OAS (1.72 +/- 0.46 mm/s) compared with sham-sensitized animals (0.90 +/- 0.15 mm/s, P < 0.05); Vmax for TSM from Cap-Aer (0.88 +/- 0.11 mm/s) was not different from control TSM (1.13 +/- 0.08 mm/s, P = NS). Similarly, maximal shortening (delta max) was augmented in TSM from OAS (1.01 +/- 0.15 mm) compared with sham-sensitized animals (0.72 +/- 0.14 mm, P < 0.05); delta max for TSM from Cap-Aer animals (0.65 +/- 0.11 mm) was not different from saline aerosol controls (0.71 +/- 0.15 mm, P = NS). We demonstrate Vmax and delta max are augmented in TSM after ovalbumin sensitization; in contrast, neurogenic inflammation caused by capsaicin has no effect on isolated TSM contractility in vitro. These data suggest that airway hyperresponsiveness in vivo that occurs in association with immunogenic or neurogenic inflammation may result from different effects of these types of inflammation on airway smooth muscle.

Na+/Ca2+ exchange and its role in intracellular Ca2+ regulation in guinea pig detrusor smooth muscle

2001 ◽  
Vol 280 (5) ◽  
pp. C1090-C1096 ◽  
Author(s):  
C. Wu ◽  
C. H. Fry
Keyword(s):  
Smooth Muscle ◽  
Membrane Potential ◽  
Guinea Pig ◽  
Outward Current ◽  
Detrusor Smooth Muscle ◽  
Small Rise ◽  
Intracellular Ca ◽  
Net Flux ◽  
Isolated Smooth Muscle Cells

The role of Na+/Ca2+ exchange in regulating intracellular Ca2+ concentration ([Ca2+]i) in isolated smooth muscle cells from the guinea pig urinary bladder was investigated. Incremental reduction of extracellular Na+ concentration resulted in a graded rise of [Ca2+]i; 50–100 μM strophanthidin also increased [Ca2+]i. A small outward current accompanied the rise of [Ca2+]i in low-Na+ solutions (17.1 ± 1.8 pA in 29.4 mM Na+). The quantity of Ca2+ influx through the exchanger was estimated from the charge carried by the outward current and was ∼30 times that which is necessary to account for the rise of [Ca2+]i, after correction was made for intracellular Ca2+ buffering. Ca2+ influx through the exchanger was able to load intracellular Ca2+ stores. It is concluded that the level of resting [Ca2+]i is not determined by the exchanger, and under resting conditions (membrane potential −50 to −60 mV), there is little net flux through the exchanger. However, a small rise of intracellular Na+ concentration would be sufficient to generate significant net Ca2+ influx.

Effects of initial length on intrinsic tone in guinea pig tracheal smooth muscle

1998 ◽  
Vol 275 (6) ◽  
pp. L1026-L1030 ◽  
Author(s):  
Martin Bard ◽  
Sergio Salmeron ◽  
Catherine Coirault ◽  
Francois-Xavier Blanc ◽  
Yves Lecarpentier
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Isometric Force ◽  
Muscle Length ◽  
Tracheal Smooth Muscle ◽  
Before And After ◽  
Active Nature ◽  
The Difference ◽  
Resting Tone ◽  
The Relationship

In the guinea pig, tracheal smooth muscle (TSM) exhibits intrinsic tone (IT). The active nature of IT suggests that it could be influenced by muscle length and load. In the guinea pig, IT is entirely suppressed by the cyclooxygenase inhibitor indomethacin. IT could be measured as the difference between resting tone before and after indomethacin addition. We examined, in electrically stimulated TSM strips ( n= 9), the influence of initial muscle length ( L i) on IT, the relationship between IT and the maximum extent of relaxation (ΔF1), and the influence of indomethacin on active isometric force. When L i decreased from 100 to 75% of optimal L i, there was a significant decrease in IT (from 12.0 ± 0.2 to 5.3 ± 0.1 mN; P < 0.001). Over the range of L i studied, ΔF1 underestimated the amount of IT, but there was a close linear relationship between ΔF1 and IT ( r = 0.9). Compared with the basal state, indomethacin increased active isometric force (from 9.5 ± 1.0 to 19.7 ± 2.0 mN at optimal L i; P < 0.001) and induced its length dependency. In guinea pig TSM, L i was an important determinant of IT.

scholarly journals Involvement of gap junctions between smooth muscle cells in sustained hypoxic pulmonary vasoconstriction development: a potential role for 15-HETE and 20-HETE

2016 ◽  
Vol 310 (8) ◽  
pp. L772-L783 ◽  
Author(s):  
Igor V. Kizub ◽  
Anand Lakhkar ◽  
Vidhi Dhagia ◽  
Sachindra R. Joshi ◽  
Houli Jiang ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Gap Junctions ◽  
Force Measurement ◽  
Isometric Force ◽  
Hypoxic Pulmonary Vasoconstriction ◽  
Muscle Cells ◽  
Cytochrome P450 Monooxygenases ◽  
Prostaglandin E ◽  
Pulmonary Vasoconstriction

In response to hypoxia, the pulmonary artery normally constricts to maintain optimal ventilation-perfusion matching in the lung, but chronic hypoxia leads to the development of pulmonary hypertension. The mechanisms of sustained hypoxic pulmonary vasoconstriction (HPV) remain unclear. The aim of this study was to determine the role of gap junctions (GJs) between smooth muscle cells (SMCs) in the sustained HPV development and involvement of arachidonic acid (AA) metabolites in GJ-mediated signaling. Vascular tone was measured in bovine intrapulmonary arteries (BIPAs) using isometric force measurement technique. Expression of contractile proteins was determined by Western blot. AA metabolites in the bath fluid were analyzed by mass spectrometry. Prolonged hypoxia elicited endothelium-independent sustained HPV in BIPAs. Inhibition of GJs by 18β-glycyrrhetinic acid (18β-GA) and heptanol, nonspecific blockers, and Gap-27, a specific blocker, decreased HPV in deendothelized BIPAs. The sustained HPV was not dependent on Ca2+entry but decreased by removal of Ca2+and by Rho-kinase inhibition with Y-27632. Furthermore, inhibition of GJs decreased smooth muscle myosin heavy chain (SM-MHC) expression and myosin light chain phosphorylation in BIPAs. Interestingly, inhibition of 15- and 20-hydroxyeicosatetraenoic acid (HETE) synthesis decreased HPV in deendothelized BIPAs. 15-HETE- and 20-HETE-stimulated constriction of BIPAs was inhibited by 18β-GA and Gap-27. Application of 15-HETE and 20-HETE to BIPAs increased SM-MHC expression, which was also suppressed by 18β-GA and by inhibitors of lipoxygenase and cytochrome P450 monooxygenases. More interestingly, 15,20-dihydroxyeicosatetraenoic acid and 20-OH-prostaglandin E2, novel derivatives of 20-HETE, were detected in tissue bath fluid and synthesis of these derivatives was almost completely abolished by 18β-GA. Taken together, our novel findings show that GJs between SMCs are involved in the sustained HPV in BIPAs, and 15-HETE and 20-HETE, through GJs, appear to mediate SM-MHC expression and contribute to the sustained HPV development.

Functional expression of the GABAB receptor in human airway smooth muscle

2006 ◽  
Vol 291 (5) ◽  
pp. L923-L931 ◽  
Author(s):  
Yoko Osawa ◽  
Dingbang Xu ◽  
David Sternberg ◽  
Joshua R. Sonett ◽  
Jeanine D’Armiento ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Airway Smooth Muscle ◽  
Gabab Receptor ◽  
Splice Variants ◽  
Functional Expression ◽  
Functional Coupling ◽  
Human Airway Smooth Muscle ◽  
Human Airway ◽  
Erk Phosphorylation

γ-Aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the mammalian central nervous system and exerts its actions via both ionotropic (GABAA/GABAC) and metabotropic (GABAB) receptors (R). In addition to their location on neurons, GABA and functional GABAB receptors have been detected in nonneuronal cells in peripheral tissue. Although the GABABR has been shown to function as a prejunctional inhibitory receptor on parasympathetic nerves in the lung, the expression and functional coupling of GABAB receptors to Gi in airway smooth muscle itself have never been described. We detected the mRNA encoding multiple-splice variants of the GABABR1 and GABABR2 in total RNA isolated from native human and guinea pig airway smooth muscle and from RNA isolated from cultured human airway smooth muscle (HASM) cells. Immunoblots identified the GABABR1 and GABABR2 proteins in human native and cultured airway smooth muscle. The GABABR1 protein was immunohistochemically localized to airway smooth muscle in guinea pig tracheal rings. Baclofen, a GABABR agonist, elicited a concentration-dependent stimulation of [35S]GTPγS binding in HASM homogenates that was abrogated by the GABABR antagonist CGP-35348. Baclofen also inhibited adenylyl cyclase activity and induced ERK phosphorylation in HASM. Another GABABR agonist, SKF-97541, mimicked while pertussis toxin blocked baclofen’s effect on ERK phosphorylation, implicating Gi protein coupling. Functional GABAB receptors are expressed in HASM. GABA may modulate an uncharacterized signaling cascade via GABAB receptors coupled to the Gi protein in airway smooth muscle.

Ablation of the SERCA3 gene alters epithelium-dependent relaxation in mouse tracheal smooth muscle

1999 ◽  
Vol 277 (2) ◽  
pp. L264-L270 ◽  
Author(s):  
James Kao ◽  
Christopher N. Fortner ◽  
Lynne H. Liu ◽  
Gary E. Shull ◽  
Richard J. Paul
Keyword(s):  
Smooth Muscle ◽  
Epithelial Cell ◽  
Isometric Force ◽  
Wild Type ◽  
Gene Ablation ◽  
Smooth Muscle Function ◽  
Intracellular Ca ◽  
In The Wild ◽  
Oxide Synthase ◽  
Transient Relaxation

Sarcoplasmic/endoplasmic reticulum Ca2+-ATPase 3 (SERCA3), an isoform of the intracellular Ca2+ pump that has been shown to mediate endothelium-dependent relaxation of vascular smooth muscle, is also expressed in tracheal epithelium. To determine its possible role in regulation of airway mechanical function, we compared tracheal contractility in gene-targeted mice deficient in SERCA3 (SERCA3−) with that in wild-type tracheae. Cumulative addition of ACh elicited concentration-dependent increases in isometric force (ED50 = 2 μM, maximum force = 8 mN/mm2) that were identical in SERCA3− and wild-type tracheae. After ACh stimulation, substance P (SP) elicited a transient relaxation (42.6 ± 3.2%, n = 28) in both tracheae. However, the rate of relaxation was significantly ( P < 0.04, n = 9) more rapid in the wild-type [half-time ( t ½) = 34.3 s] than in the SERCA3−( t ½ = 61.6 s) trachea. The SP relaxation was reduced by rubbing the trachea, indicative of epithelial cell involvement. This was verified using a perfused trachea preparation. SP in the outside medium had no effect, whereas SP in the perfusate bathing the epithelial side elicited a relaxation. Nitric oxide synthase inhibition (0.2 mM N ω-nitro-l-arginine) reduced the SP relaxation by 36.5 ± 12.5%, whereas the SP effect was abolished by eicosanoid inhibition (10 μM indomethacin). ATP also elicited an epithelium-dependent relaxation similar to SP but with a more rapid relaxation in the SERCA3−trachea than in the wild-type trachea. Our results indicate that SERCA3 gene ablation does not directly affect smooth muscle, which is consistent with the distribution of the isoform, but suggest that SERCA3 plays a role in epithelial cell modulation of airway smooth muscle function.

Simultaneous changes in intracellular calcium and tension induced by endothelin-1 and sarafotoxin S6c in guinea pig isolated gallbladder: influence of indomethacin

2002 ◽  
Vol 80 (5) ◽  
pp. 458-463 ◽  
Author(s):  
Alcíbia M Cardozo ◽  
Pedro D'Orléans-Juste ◽  
Ghassan Bkaily ◽  
Giles A Rae
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Intracellular Calcium ◽  
Fluorescence Intensity ◽  
Receptor Agonist ◽  
Muscle Tension ◽  
Strongly Correlated ◽  
Receptor Stimulation ◽  
Endothelin 1 ◽  
Intracellular Ca

The relationships between changes in intracellular Ca2+ and smooth muscle tension triggered by endothelin-1 and the selective endothelin ETB receptor agonist sarafotoxin S6c, as well as their susceptibility to modification by the nonselective cyclooxygenase blocker indomethacin, were assessed in guinea pig isolated gallbladder strips. Cumulative additions of either agonist (1, 10, and 100 nM) induced simultaneous graded, strongly correlated, slowly developing, and sustained changes in tension and intracellular Ca+2 (Fura-2 technique). Sarafotoxin S6c was more effective than endothelin-1 in raising intracellular Ca2+ at 1 or 10 nM, but their abilities to cause contractions were similar at all concentrations. Indomethacin (5.6 µM) markedly inhibited the changes in both intracellular Ca2+ and tension caused by all concentrations of sarafotoxin S6c (in response to 100 nM, increases in Ca+2 fluorescence intensity and tension were inhibited from 7.7 ± 0.7 to 4.0 ± 0.4% and from 460 ± 100 to 160 ± 40 mg, respectively) but only reduced the contraction triggered by 100 nM endothelin-1 (from 560 ± 100 to 230 ± 70 mg). Endothelin-1 caused greater prostacyclin release from gallbladder than sarafotoxin S6c (at 100 nM, 6-keto-PGF1α levels in the medium rose 4.8- and 2.8-fold, respectively; P < 0.05) and slightly increased thromboxane A2 release (1.6-fold; P < 0.05). Thus, gallbladder contractions triggered by combined ETA/ETB or selective ETB receptor stimulation (with endothelin-1 or sarafotoxin S6c, respectively) are strongly correlated with increases in intracellular Ca2+ but differentially affected by indomethacin. It remains to be assessed if this difference is because endothelin-1 triggers greater prostacyclin release than sarafotoxin S6c and (or) is due to the coupling of ETA and ETB receptors to distinct patterns of generation of cyclooxygenase-derived eicosanoids.Key words: endothelin, gallbladder, prostacyclin, indomethacin, calcium.

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