Effects of salbutamol on intracellular calcium oscillations in porcine airway smooth muscle

1997 ◽  
Vol 82 (6) ◽  
pp. 1836-1843 ◽  
Author(s):  
Y. S. Prakash ◽  
H. F. M. Van Der Heijden ◽  
M. S. Kannan ◽  
G. C. Sieck
Keyword(s):  
Smooth Muscle ◽  
Intracellular Calcium ◽  
Airway Smooth Muscle ◽  
Inhibitory Effect ◽  
Calcium Oscillations ◽  
Adrenoceptor Agonist ◽  
Intracellular Ca ◽  
Adrenoceptor Agonists ◽  
A Cell ◽  
Agonist Concentration

Prakash, Y. S., H. F. M. van der Heijden, M. S. Kannan, and G. C. Sieck. Effects of salbutamol on intracellular calcium oscillations in porcine airway smooth muscle. J. Appl. Physiol. 82(6): 1836–1843, 1997.—Relaxation of airway smooth muscle (ASM) by β-adrenoceptor agonists involves reduction of intracellular Ca2+concentration ([Ca2+]i). In porcine ASM cells, acetylcholine induces [Ca2+]ioscillations that display frequency modulation by agonist concentration and basal [Ca2+]i. We used real-time confocal microscopy to examine the effect of salbutamol (1 nM to 1 μM), a β2-adrenoceptor agonist, on [Ca2+]ioscillations in freshly dissociated porcine ASM cells. Salbutamol decreased the frequency of [Ca2+]ioscillations in a concentration-dependent fashion, completely inhibiting the oscillations at 1 μM. These effects were mimicked by a cell-permeant analog of adenosine 3′,5′-cyclic monophosphate. The inhibitory effect of salbutamol was partially reversed by BAY K 8644. Salbutamol reduced [Ca2+]ieven when sarcoplasmic reticulum (SR) Ca2+ reuptake and Ca2+ influx were blocked. Lanthanum blockade of Ca2+ efflux attenuated the inhibitory effect of salbutamol on [Ca2+]i. The [Ca2+]iresponse to caffeine was unaffected by salbutamol. On the basis of these results, we conclude that β2-adrenoceptor agonists have little effect on SR Ca2+ release in ASM cells but reduce [Ca2+]iby inhibiting Ca2+ influx through voltage-gated channels and by enhancing Ca2+ efflux.

Evidence against the role of α1-adrenoceptor reserve in buffering the inhibitory effect of nifedipine on the contractility of canine vascular smooth muscle

1990 ◽  
Vol 68 (10) ◽  
pp. 1346-1350 ◽  
Author(s):  
Yong-Yuan Guan ◽  
Chiu-Yin Kwan ◽  
Edwin E. Daniel
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Saphenous Vein ◽  
Mesenteric Artery ◽  
Inhibitory Effect ◽  
Contractile Responses ◽  
Intracellular Ca ◽  
Adrenoceptor Agonists ◽  
The Difference ◽  
Muscle Calcium

The relationship between the postsynaptic α1-adrenoceptor reserve and the sensitivity of vasoconstriction induced by α-adrenoceptor agonists to the dihydropyridine Ca2+ entry blocker nifedipine was investigated in isolated muscle strips of dog mesenteric artery (DMA) and saphenous vein (DSV). The amplitudes of the contractile responses of DMA induced by phenylephrine were the same as those in DSV in the presence and in the absence of extracellular Ca2+. The use of 3 × 10−9 M phenoxybenzamine to irreversibly block the α1-adrenoceptors revealed a marked difference in the size of the α1-adrenoceptor reserve between DMA (40%) and DSV (7%). In spite of a larger receptor reserve, the contractile responses induced by phenylephrine in DMA were more sensitive to nifedipine compared with those in DSV. These results suggest that the postsynaptic α1-adrenoceptor reserve in vascular smooth muscle, at least in DMA and DSV, does not play an important role in buffering the inhibitory effect of nifedipine on the contractile response to a full agonist of α1-adrenoceptors. Other factors, such as the difference in the membrane depolarizing effect, the ability to utilize intracellular Ca2+ for contraction, and the possible existence of α1-adrenoceptor subtypes, may contribute to the different inhibitory effects of nifedipine on these blood vessels.Key words: adrenoceptors, nifedipine, smooth muscle, calcium, saphenous vein, mesenteric artery.

Differential effects of soluble and particulate guanylyl cyclase on Ca2+ sensitivity in airway smooth muscle

2002 ◽  
Vol 92 (1) ◽  
pp. 257-263 ◽  
Author(s):  
Edwin H. Rho ◽  
William J. Perkins ◽  
Robert R. Lorenz ◽  
David O. Warner ◽  
Keith A. Jones
Keyword(s):  
Smooth Muscle ◽  
Airway Smooth Muscle ◽  
Guanylyl Cyclase ◽  
Soluble Guanylyl Cyclase ◽  
Rightward Shift ◽  
Muscarinic Stimulation ◽  
Intracellular Ca ◽  
A Cell ◽  
The Relationship ◽  
Stimulation Of

Maximal relaxation of airway smooth muscle (ASM) in response to atrial natriuretic peptide (ANP), which stimulates particulate guanylyl cyclase (pGC), is less than that produced by nitric oxide (NO) and other compounds that stimulate soluble guanylyl cyclase (sGC). We hypothesized that stimulation of pGC relaxes ASM only by decreasing intracellular Ca2+ concentration ([Ca2+]i), whereas stimulation of sGC decreases both [Ca2+]i and the force developed for a given [Ca2+]i (i.e., the Ca2+ sensitivity) during muscarinic stimulation. We measured the relationship between force and [Ca2+]i (using fura 2) under control conditions (using diltiazem to change [Ca2+]i) and during exposure to ANP, diethylamine-NO (DEA-NO), sodium nitroprusside (SNP), and the Sp diastereoisomer of β-phenyl-1, N 2-etheno-8-bromoguanosine-3′,5′-cyclic monophosphorothionate ( Sp-8-Br-PET-cGMPS), a cell-permeant analog of cGMP. Addition of DEA-NO, SNP, or Sp-8-Br-PET-cGMPS decreased both [Ca2+]i and force, causing a significant rightward shift of the force-[Ca2+]irelationship. In contrast, with ANP exposure, the force-[Ca2+]i relationship was identical to control, such that ANP produced relaxation solely by decreasing [Ca2+]i. Thus, during muscarinic stimulation, stimulation of pGC relaxes ASM exclusively by decreasing [Ca2+]i, whereas stimulation of sGC decreases both [Ca2+]i and Ca2+sensitivity.

Muscarinic inhibition of adenylyl cyclase regulates intracellular calcium in single airway smooth muscle cells

1996 ◽  
Vol 270 (2) ◽  
pp. L208-L214 ◽  
Author(s):  
J. M. Madison ◽  
H. Yamaguchi
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Intracellular Calcium ◽  
Adenylyl Cyclase ◽  
Airway Smooth Muscle ◽  
Muscle Cells ◽  
Inhibitory Effect ◽  
Airway Smooth Muscle Cells ◽  
Muscarinic Agonists ◽  
Cyclic Monophosphate

To determine whether muscarinic agonists attenuated isoproterenol-stimulated decreases in intracellular calcium concentration ([Ca2+]i), changes in [Ca2+]i were measured in single airway smooth muscle cells using ratiometric analysis of fura 2 fluorescence. Isoproterenol (10(-5) M) and 8-bromoadenosine 3',5'-cyclic monophosphate (8-BrcAMP) decreased [Ca2+]i by 24 +/- 3% (P < 0.05, n= 28) and 17 +/- 1% (P < 0.05, n = 6), respectively. The decreased [Ca2+]i in response to isoproterenol was inhibited by propranolol (10(-6) M) and Rp-adenosine 3',5'-cyclic monophosphothioate (Rp-cAMPS) (10-40 microM). In subsequent experiments assessing the effects of muscarinic agonists, isoproterenol did not decrease [Ca2+]i in the presence of carbachol (5 x 10(-8) M) (6 +/- 8% increase; NS, n = 8). To determine the mechanism underlying this inhibitory effect of carbachol, cells were loaded with 4,5-dimethoxy-2-nitrobenzyl adenosine-3',5'-cyclic monophosphate (caged cAMP). For cells loaded with 20 microM caged cAMP, photolysis of caged cAMP decreased basal [Ca2+]i by 28 +/- 3% (P < 0.05, n = 12). In the presence of carbachol (5 x 10(-8) M), photolysis of caged cAMP still induced a 27 +/- 4% decrease in [Ca2+]i (P < 0.05, n = 12). We concluded that a low concentration of carbachol did attenuate isoproterenol-stimulated decreases in [Ca2+]i. Because low concentrations of carbachol attenuated the decreases in [Ca2+]i stimulated by isoproterenol but not the comparable decreases stimulated by cAMP directly, we concluded that the inhibition of adenylyl cyclase activity by muscarinic agonists contributed to the regulation of [Ca2+]i in airway smooth muscle cells. The findings suggested that physiological levels of cholinergic stimulation inhibit adenylyl cyclase, thereby attenuating the effects that beta-adrenergic agonists have on [Ca2+]i.

scholarly journals Altered CD38/Cyclic ADP-Ribose Signaling Contributes to the Asthmatic Phenotype

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Joseph A. Jude ◽  
Mythili Dileepan ◽  
Reynold A. Panettieri ◽  
Timothy F. Walseth ◽  
Mathur S. Kannan
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Intracellular Calcium ◽  
Airway Smooth Muscle ◽  
Airway Hyperresponsiveness ◽  
Map Kinases ◽  
Muscle Cells ◽  
Airway Smooth Muscle Cells ◽  
Cd38 Expression ◽  
Cyclic Adp Ribose

CD38 is a transmembrane glycoprotein expressed in airway smooth muscle cells. The enzymatic activity of CD38 generates cyclic ADP-ribose from β-NAD. Cyclic ADP-ribose mobilizes intracellular calcium during activation of airway smooth muscle cells by G-protein-coupled receptors through activation of ryanodine receptor channels in the sarcoplasmic reticulum. Inflammatory cytokines that are implicated in asthma upregulate CD38 expression and increase the calcium responses to contractile agonists in airway smooth muscle cells. The augmented intracellular calcium responses following cytokine exposure of airway smooth muscle cells are inhibited by an antagonist of cyclic ADP-ribose. Airway smooth muscle cells from CD38 knockout mice exhibit attenuated intracellular calcium responses to agonists, and these mice have reduced airway response to inhaled methacholine. CD38 also contributes to airway hyperresponsiveness as shown in mouse models of allergen or cytokine-induced inflammatory airway disease. In airway smooth muscle cells obtained from asthmatics, the cytokine-induced CD38 expression is significantly enhanced compared to expression in cells from nonasthmatics. This differential induction of CD38 expression in asthmatic airway smooth muscle cells stems from increased activation of MAP kinases and transcription through NF-κB, and altered post-transcriptional regulation through microRNAs. We propose that increased capacity for CD38 signaling in airway smooth muscle in asthma contributes to airway hyperresponsiveness.

Isotonic relaxation of control and sensitized airway smooth muscle

2005 ◽  
Vol 83 (10) ◽  
pp. 941-951 ◽  
Author(s):  
N L Stephens ◽  
A Fust ◽  
H Jiang ◽  
W Li ◽  
X Ma
Keyword(s):  
Smooth Muscle ◽  
Intracellular Calcium ◽  
Airway Smooth Muscle ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Phase Iii ◽  
Contractile Element ◽  
Second Phase ◽  
Half Time ◽  
Phase Phase

Smooth muscle relaxation has most often been studied in isometric mode. However, this only tells us about the stiffness properties of the bronchial wall and thus only about wall capacitative properties. It tells us little about airflow. To study the latter, which of course is the meaningful parameter in regulation of ventilation and in asthma, we studied isotonic shortening of bronchial smooth muscle (BSM) strips. Failure of BSM to relax could be another important factor in maintaining high airway resistance. To analyze relaxation curves, we developed an index of isotonic relaxation, t1/2(P, lCE), which is the half-time for relaxation that is independent of muscle load (P) and of initial contractile element length (lCE). This index was measured in curves of relaxation initiated at 2 s (normally cycling crossbridges) and at 10 s (latch-bridges). At 10 s no difference was seen for adjusted t1/2(P, lCE) between curves obtained from control and sensitized BSM, (8.38 ± 0.92 s vs. 7.78 ± 0.93 s, respectively). At 2 s the half-time was almost doubled in the sensitized BSM (6.98 ± 0.01 s (control) vs. 12.74 ± 2.5 s (sensitized)). Thus, changes in isotonic relaxation are only seen during early contraction. Using zero load clamps, we monitored the time course of velocity during relaxation and noted that it varied according to 3 phases. The first phase (phase i) immediately followed cessation of electrical field stimulation (EFS) at 10 s and showed almost the same velocity as during the latter 1/3 of shortening; the second phase (phase ii) was linear in shape and is associated with zero load velocity, we speculate it could stem from elastic recoil of the cells' internal resistor; and the third phase (phase iii) was convex downwards. The zero load velocities in phase iii showed a surprising spontaneous increase suggesting reactivation of the muscle. Measurements of intracellular calcium (Fura-2 study) and of phosphorylation of the 20 kDa myosin light chain showed simultaneous increments, indicating phase iii represented an active process. Studies are under way to determine what changes occur in these 3 phases in a sensitized muscle. And of course, in the context of this conference, just what role the plastic properties of the muscle play in relaxation requires serious consideration.Key words: airway smooth muscle, sensitized smooth muscle, isotonic relaxation, intracellular calcium transients, myosin light chain (20 kDa) phosphorylation.

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