In vitro reactivity of ventral aorta to acetylcholine and noradrenaline in yellow freshwater eel (Anguilla anguilla L.) acclimatized to 10.1 MPa hydrostatic pressure

2000 ◽  
Vol 78 (11) ◽  
pp. 897-903 ◽  
Author(s):  
François Guerrero ◽  
Mickael Theron ◽  
Philippe Sebert
Keyword(s):  
Smooth Muscle ◽  
Hydrostatic Pressure ◽  
Vascular Smooth Muscle ◽  
Dose Response ◽  
Vascular Reactivity ◽  
Anguilla Anguilla ◽  
Dry Weight ◽  
Isometric Tension ◽  
Response Curves

We examined in vitro vascular reactivity of eels previously acclimatized to 10.1 MPa hydrostatic pressure (HP) for 21 days. The isometric tension developed by ventral aortic rings was measured at atmospheric pressure. Dose-response curves for either acetylcholine (ACh) or noradrenaline (NA), as well as contractions evoked by 80 mM K+, were compared with time-matched experiments conducted on rings obtained from control eels. Results showed that neither the optimal tension nor the maximal force of the K+-evoked contraction were significantly modified, suggesting that acclimatization to high HP did not change the vascular smooth muscle contractile machinery. The dose-response curve to ACh was not significantly changed. Conversely, although NA always relaxed aortic rings, the response of acclimatized eels was significantly reduced over the entire range of the agonist concentration tested (10-8 to 10-3 M), except for the lowest one (10-9 M). The maximal amplitude of the NA-induced relaxation was significantly reduced in aortic rings from acclimatized eels as compared with non-acclimatized samples (339.3 ± 86.5 vs. 744.3 ± 72.1 mg·mg-1 dry weight, P < 0.005). Our results suggest that acclimatization to high HP could selectively alter the control of vascular tone by catecholamines.Key words: fish, high pressure, vascular smooth muscle, adrenoceptors, cholinergic receptors.

Levobupivacaine-induced contraction of isolated rat aorta is calcium dependent

2011 ◽  
Vol 89 (7) ◽  
pp. 467-476 ◽  
Author(s):  
Ji Seok Baik ◽  
Ju-Tae Sohn ◽  
Seong-Ho Ok ◽  
Jae-Gak Kim ◽  
Hui-Jin Sung ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Smooth Muscle ◽  
Calcium Influx ◽  
Rat Aorta ◽  
Isometric Tension ◽  
Guanosine Monophosphate ◽  
Response Curves ◽  
Calcium Dependent ◽  
Isolated Rat

Levobupivacaine is a long-acting local anesthetic that intrinsically produces vasoconstriction in isolated vessels. The goals of this study were to investigate the calcium-dependent mechanism underlying levobupivacaine-induced contraction of isolated rat aorta in vitro and to elucidate the pathway responsible for the endothelium-dependent attenuation of levobupivacaine-induced contraction. Isolated rat aortic rings were suspended to record isometric tension. Cumulative levobupivacaine concentration–response curves were generated in either the presence or absence of the antagonists verapamil, nifedipine, SKF-96365, 2-aminoethoxydiphenylborate, Gd3+, NW-nitro-l-arginine methyl ester (L-NAME), 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ), and methylene blue, either alone or in combination. Verapamil, nifedipine, SKF-96365, 2-aminoethoxydiphenylborate, low calcium concentrations, and calcium-free Krebs solution attenuated levobupivacaine-induced contraction. Gd3+ had no effect on levobupivacaine-induced contraction. Levobupivacaine increased intracellular calcium levels in vascular smooth muscle cells. L-NAME, ODQ, and methylene blue increased levobupivacaine-induced contraction in endothelium-intact aorta. SKF-96365 attenuated calcium-induced contraction in a previously calcium-free isotonic depolarizing solution containing 100 mmol/L KCl. Levobupivacaine-induced contraction of rat aortic smooth muscle is mediated primarily by calcium influx from the extracellular space mainly via voltage-operated calcium channels and, in part, by inositol 1,4,5-trisphosphate receptor-mediated release of calcium from the sarcoplasmic reticulum. The nitric oxide – cyclic guanosine monophosphate pathway is involved in the endothelium-dependent attenuation of levobupivacaine-induced contraction.

Histamine tachyphylaxis in canine airways despite prostaglandin synthesis inhibition

1988 ◽  
Vol 65 (5) ◽  
pp. 1944-1949 ◽  
Author(s):  
P. J. Antol ◽  
S. J. Gunst ◽  
R. E. Hyatt
Keyword(s):  
Smooth Muscle ◽  
Dose Response ◽  
Prostaglandin Synthesis ◽  
Response Curves ◽  
Synthesis Inhibition ◽  
High Concentrations ◽  
Alpha Chloralose ◽  
Prostaglandin Synthesis Inhibitors

Tachyphylaxis to aerosolized histamine was studied in dogs anesthetized with thiamylal after pretreatment with prostaglandin synthesis inhibitors. Three consecutive histamine dose-response curves were obtained in nine dogs pretreated with 5 mg/kg indomethacin; two of these nine were also pretreated with 10 mg/kg indomethacin. Seven of the nine dogs were pretreated with 4 mg/kg sodium meclofenamate; four of these seven were also pretreated with 12 mg/kg. All dogs had tachyphylaxis at high concentrations of histamine regardless of inhibitor used. Pretreatment with indomethacin while the dogs were under alpha-chloralose-urethan anesthesia gave similar results. Histamine tachyphylaxis was also studied both in the presence and in the absence of indomethacin in tracheal smooth muscle strips obtained from seven additional dogs. A decrease in the median effective dose to histamine was observed in the indomethacin-treated strips, but tachyphylaxis to histamine remained. We conclude that prostaglandin synthesis inhibition does not reverse histamine tachyphylaxis either in vivo or in vitro. Thus the mechanism of histamine tachyphylaxis remains unexplained.

Mechanisms of histamine-induced contraction of canine airway smooth muscle

1983 ◽  
Vol 55 (1) ◽  
pp. 22-26 ◽  
Author(s):  
S. Shore ◽  
C. G. Irvin ◽  
T. Shenkier ◽  
J. G. Martin
Keyword(s):  
Smooth Muscle ◽  
Dose Response ◽  
Response Curve ◽  
Line Tension ◽  
Isometric Tension ◽  
Dose Response Curve ◽  
Base Line ◽  
Histamine Concentration ◽  
Release Of Acetylcholine

We studied the effects of atropine (10(-10) to 10(-6) M), tetrodotoxin (TTX) (10(-6) g/ml), and neostigmine (10(-7) M) on the histamine dose-response curve of canine tracheal smooth muscle (TSM) in vitro. Pretreatment with atropine or TTX reduced base-line tension in some TSM samples, whereas neostigmine invariably caused contraction of TSM. All concentrations of atropine reduced the maximum isometric tension produced by histamine (Tmax). With 10(-6), 10(-8), and 10(-10) M atropine, Tmax was 57, 74, and 88%, respectively, of its value in paired control samples. Atropine, 10(-9) to 10(-6) M, increased the concentration of histamine which produced 20% of Tmax, whereas 10(-6) M also increased the concentration required to produce 50% of Tmax. TTX reduced tension produced by low concentrations of histamine but had no effect at higher concentrations. Neostigmine shifted the histamine dose-response curve and caused greater tension for any given histamine concentration; Tmax increased by 30% (P less than 0.05). Our data are consistent with spontaneous release of acetylcholine from cholinergic nerves in the airway tissue and suggest that histamine either accelerates this release or interacts supra-additively with the acetylcholine at the smooth muscle.

Length-dependent sensitivity in vascular smooth muscle

1981 ◽  
Vol 241 (4) ◽  
pp. H557-H563 ◽  
Author(s):  
J. M. Price ◽  
D. L. Davis ◽  
E. B. Knauss
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Dose Response ◽  
Length Change ◽  
Maximal Response ◽  
Anterior Tibial Artery ◽  
Response Curves ◽  
Anterior Tibial ◽  
Dose Response Curves ◽  
Best Fit

Dose-response curves were obtained from dog anterior tibial artery rings at various lengths (L) to determine whether sensitivity to norepinephrine (NE) and potassium (K+) depends on arterial circumference. The dose for half maximal response (ED50) was determined by graphical estimation and by calculation from a best fit curve. For both NE and K+: 1) ED50 was lowest (most sensitive) at L for maximum active force (Lmax) and increased significantly as L decreased from Lmax; 2) ED50 at 1.0 and 1.15 Lmax was not significantly different; 3) ED50 of repeated dose-response curves at Lmax was not significantly different; and 4) when the direction of length change was reversed (from decreasing to increasing), the direction of change in ED50 was also reversed (from increasing to decreasing). Change in the dose for 10% maximal response was the same as ED50. The results did not depend on the method of determining ED50 or on whether responses were expressed as absolute values or as relative values. The results show that sensitivity of vascular smooth muscle depends on L and that the length-sensitivity relation is similar to the length-active tension relation. Similarity of results for NE and K+ indicate that length-dependent sensitivity does not depend on the method of stimulation.

Characterization of sulfidopeptide leukotriene responses in sheep tracheal smooth muscle in vitro

1991 ◽  
Vol 69 (6) ◽  
pp. 805-811 ◽  
Author(s):  
K. Tomioka ◽  
J. T. Jackowski ◽  
W. M. Abraham
Keyword(s):  
Smooth Muscle ◽  
Dose Response ◽  
Tracheal Smooth Muscle ◽  
Response Curves ◽  
Leukotriene Antagonist ◽  
Dose Response Curves ◽  
The Right ◽  
Glutamyl Transpeptidase

We have investigated the effects of leukotrienes (LTs) on isolated tracheal smooth muscle from sheep sensitive to Ascaris suum antigen. LTC4 and LTD4 produced dose-dependent contractions of sheep trachea, but LTE4 was virtually inactive. YM-17690, a non-analogous LT agonist, produced no contractile response up to 100 μM. Indomethacin (5 μM) had no effect on LTC4- and LTD4-induced contractions. L-Serine borate (45 mM), an inhibitor of γ-glutamyl transpeptidase, shifted the dose–response curve of LTC4 to the left by 161-fold, and L-cysteine (6 mM), an inhibitor of aminopeptidase, shifted the dose–response curves of LTC4 and LTD4 to the left by 67- and 23-fold, respectively. YM-16638 (1 μM), an LT antagonist, shifted the dose–response curves of LTC4 and LTD4 to the right with pKB values of 6.57 and 7.13, respectively. YM-16638 did not affect LTC4-induced contractions of L-serine borate-treated tissues, indicating that the compound acts only on LTD4 receptors in sheep trachea. LTE4 (1 μM) shifted the dose–response curves of LTC4 and LTD4 to the right with pKB values of 6.87 and 7.31, respectively. YM-17690 (10 μM) showed effects similar to LTE4, suggesting that the compound acts as an LTE4 agonist in sheep trachea. These results suggest that in sheep tracheal smooth muscle (a) LTC4 and LTD4 produce contractions, (b) these LT-induced contractions are not mediated by cyclooxygenase products, (c) LTC4 is converted to LTD4 and then to LTE4, and (d) the potency of the LTC4- and LTD4-induced contractions is increased when their conversion to LTE4 is inhibited. This potentiation may result from the inability of LTE4 to contract sheep trachea and (or) its antagonist actions.Key words: leukotriene antagonist, receptors, asthma.

Pentobarbital and contraction of vascular smooth muscle

1975 ◽  
Vol 229 (6) ◽  
pp. 1635-1640 ◽  
Author(s):  
BT Altura ◽  
BM Altura
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Dose Response ◽  
Mechanical Activity ◽  
Response Curves ◽  
Aortic Smooth Muscle ◽  
Dose Response Curves ◽  
Portal Veins ◽  
The Right ◽  
Dose Dependent

This study, with isolated rat aortic strips and portal veins, was undertaken to : 1) study the effects, if any, of pentobarbital Na (PTB) (5 x 10(-5) to 2 X 10(-3) M) on reactivity to epinephrine, serotonin, and KCl; 2) determine whether certain concentrations of PTB induce direct actions on aortic strips and portal veins; and 3) gain some insight into how these effects are brought about. The results indicate that PTB can: a) inhibit development of spontaneous mechanical activity in these vessels in anesthetic concentrations; b) dose-dependently attenuate contractions induced by epinephrine, serotonin, and KC1; c) cause a noncompetitive type displacement of the dose response curves of these vasoactive agents; d) attenuate Ca2+- induced contractions of potassium-depolarized aortic strips and portal veins concomitant with a dose-dependent displacement of these dose-response curves to the right; and e) rapidly relax drug as well as Ca2+ -induced contractions of aortas and portal veins. In addition, the data indicate that rat portal venous smooth muscle is more sensitive to the inhibitory actions of PTB than rat aortic smooth muscle. Overall, these data suggest that concentrations of PTB used to induce surgical anesthesia can exert profound depressant effects on at least two different types of vascular smooth muscle that may be related to actions on movement and/or translocation of Ca2+.

Propofol Potentiates Phenylephrine-induced Contraction via  Cyclooxygenase Inhibition in Pulmonary Artery Smooth Muscle

2001 ◽  
Vol 94 (5) ◽  
pp. 833-839 ◽  
Author(s):  
Koji Ogawa ◽  
Satoru Tanaka ◽  
Paul A. Murray
Keyword(s):  
Arachidonic Acid ◽  
Smooth Muscle ◽  
In Vitro Study ◽  
Isometric Tension ◽  
Relaxation Response ◽  
Response Curves ◽  
Independent Manner ◽  
Pulmonary Arterial

Background The authors previously demonstrated in vivo that the pulmonary vasoconstrictor response to the a agonist phenylephrine is potentiated during propofol anesthesia compared with the conscious state. The current in vitro study tested the hypothesis that propofol potentiates phenylephrine-induced contraction by inhibiting the synthesis and/or activity of vasodilator metabolites of the cyclooxygenase pathway. Methods Canine pulmonary arterial rings were suspended for isometric tension recording. Intracellular calcium concentration ([Ca2+]i) was measured in pulmonary arterial strips loaded with acetoxylmethyl ester of fura-2. After phenylephrine-induced contraction, propofol (10(-7) to 10(-4) M) was administered in the presence or absence of the cyclooxygenase inhibitor ibuprofen (10(-5) M). The effects of propofol on the arachidonic acid and prostacyclin relaxation-response curves were assessed. The amount of 6-keto prostaglandin F1alpha (stable metabolite of prostacyclin) released from pulmonary vascular smooth muscle in response to phenylephrine was measured with enzyme immunoassay in the presence or absence of propofol and ibuprofen. Results Propofol potentiated phenylephrine-induced contraction in pulmonary arterial rings in a concentration-dependent and endothelium-independent manner. In endothelium-denuded strips, propofol (10(-4) M) increased tension by 53+/-11%, and increased [Ca2+]i by 56+/-9%. Ibuprofen also potentiated phenylephrine-induced contraction but abolished the propofol-induced increases in tension and [Ca2+]i. Propofol had no effect on the relaxation response to prostacyclin, whereas propofol and ibuprofen attenuated the relaxation response to arachidonic acid to a similar extent. Phenylephrine markedly increased 6-keto prostaglandin F1alpha production, and this effect was virtually abolished by propofol and ibuprofen. Conclusion These results suggest that propofol potentiates alpha-adrenoreceptor-mediated pulmonary vasoconstriction by inhibiting the concomitant production of prostacyclin by cyclooxygenase.

Role of potassium channels in hypoxic relaxation of porcine bronchi in vitro

1994 ◽  
Vol 266 (3) ◽  
pp. L232-L237
Author(s):  
K. S. Lindeman ◽  
L. B. Fernandes ◽  
T. L. Croxton ◽  
C. A. Hirshman
Keyword(s):  
Smooth Muscle ◽  
Dose Response ◽  
Katp Channel ◽  
Response Curve ◽  
Channel Blocker ◽  
Katp Channels ◽  
Response Curves ◽  
Third Order

To elucidate the mechanism of hypoxic relaxation of airway smooth muscle in vitro, we investigated the role of adenosine triphosphate-sensitive potassium (KATP) channels in this response. Second- and third-order porcine bronchial rings were suspended in 10-ml organ baths containing Krebs-Henseleit solution. To demonstrate the presence of KATP channels in this tissue, bronchial rings were contracted with carbachol (1 microM) in the presence of glibenclamide (100 microM), a KATP channel blocker, or the vehicle dimethyl sulfoxide (DMSO) (0.1 ml), and dose-response curves to levcromakalim (a KATP channel opener) or isoproterenol were constructed. In separate experiments, either glibenclamide or DMSO was added to the chamber and rings were contracted with carbachol (1 microM) in the presence of 95% O2-5% CO2. At the plateau, airways were relaxed with either isoproterenol (0.1 or 0.3 microM) or hypoxia (50, 28, or 0% O2, with constant 5% CO2). Glibenclamide, when compared with DMSO, shifted the dose-response curve to levcromakalim, but not to isoproterenol. Glibenclamide attenuated hypoxic relaxation in rings exposed to 50% O2 (from 35 +/- 4% to 23 +/- 3%, n = 6, P < 0.001) and increased the time to 63% relaxation in rings exposed to 50% O2 or to 28% O2. Responses in rings exposed to 0% O2 or to isoproterenol (0.1 or 0.3 microM) were not significantly altered. The ability of glibenclamide to attenuate the maximum response to 50% O2 and to increase the time to 63% relaxation during exposure to 50 or 28% O2 suggests that one component of hypoxic bronchodilation during moderate degrees of hypoxia is opening of KATP channels.

Length-dependent sensitivity at lengths greater than Lmax in vascular smooth muscle

1983 ◽  
Vol 245 (3) ◽  
pp. H379-H384 ◽  
Author(s):  
J. M. Price ◽  
D. L. Davis ◽  
E. B. Knauss
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Dose Response ◽  
Muscle Length ◽  
Maximal Response ◽  
Anterior Tibial Artery ◽  
Active Force ◽  
Response Curves ◽  
Active Stress ◽  
Dose Response Curves

Previous work has shown that vascular smooth muscle sensitivity depends on muscle length (arterial circumference) at lengths equal to and less than that for maximum active force (Lmax). In the present study dose-response curves were obtained from dog anterior tibial artery rings at lengths equal to or longer than Lmax. The curves were compared with dose-response curves obtained at lengths less than Lmax. The agonist concentration for half maximal response (ED50) was determined by graphical estimation and by calculation from a best-fit curve. The results show that with norepinephrine (NE) stimulation 1) ED50 decreased significantly at each step when the rings were stretched from Lmax to 1.15 Lmax and then to 1.30 Lmax; 2) ED50 increased significantly when length was decreased from 1.15 to 1.00 Lmax; 3) ED50 decreased significantly at each step when the rings were stretched from 0.70 Lmax to Lmax and then to 1.30 Lmax; and 4) for NE concentration greater than the ED50 at Lmax, active stress was significantly higher at Lmax than at 0.70 Lmax or 1.30 Lmax. For an NE concentration less than the ED50 at Lmax, the active stress at 1.30 Lmax was higher than the active stress at Lmax and at 0.70 Lmax. The results show that sensitivity of vascular smooth muscle continually increases with stretch and does not have a maximum at the length for maximum active force.

Increased contractility in vascular smooth muscle of dystrophic hamsters

1983 ◽  
Vol 61 (2) ◽  
pp. 182-185 ◽  
Author(s):  
E. G. Hunter ◽  
J. Elbrink
Keyword(s):  
Animal Model ◽  
Smooth Muscle ◽  
Muscular Dystrophy ◽  
Vascular Smooth Muscle ◽  
Cumulative Dose ◽  
Dose Response ◽  
Response Curves ◽  
Collagen Protein ◽  
Dose Response Curves

To investigate the "vascular" hypothesis of muscular dystrophy, the sensitivity and contractility of aortic spiral strips of dystrophic (BIO 14.6) and normal (FIB) hamsters have been determined to various smooth muscle agonists. The results obtained with cumulative dose–response curves show that there is no increase in the sensitivity of the dystrophic compared with the normal aorta to noradrenaline, phenylephrine, isoproterenol, histamine, or 5-hydroxytryptamine. However, there was a significant increase in the force generated by aortic strips of the dystrophic animals to all agonists. Determination of noncollagen and collagen protein showed that there was no difference in the relative proportions of these proteins in the aortas from the two strains. The results show that in this animal model of dystrophy an increased response to vasopressor amines occurs and is in accordance with that expected of the vascular hypothesis.

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