scholarly journals Myofilament‐based relaxant effect of isoprenaline revealed during work‐loop contractions in rat cardiac trabeculae

2002 ◽  
Vol 544 (1) ◽  
pp. 171-182 ◽  
Author(s):  
Joanne Layland ◽  
Jonathan C. Kentish
Keyword(s):  
Relaxant Effect ◽  
Work Loop

scholarly journals Lack of synergistic interaction between quercetin and catechin in systemic and pulmonary vascular smooth muscle

2010 ◽  
Vol 105 (9) ◽  
pp. 1287-1293 ◽  
Author(s):  
Carmen Menendez ◽  
Rosario Jimenez ◽  
Laura Moreno ◽  
Pilar Galindo ◽  
Angel Cogolludo ◽  
...  
Keyword(s):  
Endothelial Dysfunction ◽  
Vascular Function ◽  
Pulmonary Arteries ◽  
Rat Aorta ◽  
Relaxant Effect ◽  
Isobolographic Analysis ◽  
Scavenging Effect ◽  
Synergistic Interactions ◽  
Pure Compounds ◽  
Intermediate Effect

Due to their ubiquitous distribution, flavonoids from different classes are commonly present together in foods. However, little is known about the interactions between them. The flavonol quercetin and the flavan-3-ol (+)-catechin are among the most abundant flavonoids in the diet. In the present study, we have analysed the interactions between these two flavonoids on vascular function using two pure compounds and mixtures of these flavonoids in 1:0·1, 1:1 or 1:10 proportions. Quercetin induced a more potent concentration-dependent relaxant effect than catechin in the isolated rat aorta, and the isobolographic analysis of the mixtures showed no synergistic or antagonistic effects between them, i.e. their effects were additive. Quercetin was more potent in mesenteric than in pulmonary arteries. Catechin had weak effects in these vessels and did not modify the effects of quercetin. Endothelial dysfunction induced by increased oxidative stress by the superoxide dismutase inhibitor diethyldithiocarbamate was prevented by quercetin, whereas catechin showed a weak effect and the 1:1 mixture an intermediate effect compared with the pure compounds. Quercetin but not catechin showed a pro-oxidant and NO-scavenging effect, which was not prevented by catechin. In conclusion, catechin was less potent than quercetin as a vasodilator, pro-oxidant or to prevent endothelial dysfunction, and there were no synergistic interactions between quercetin and catechin.

Fatigue of mouse soleus muscle, using the work loop technique.

1997 ◽  
Vol 200 (22) ◽  
pp. 2907-2912 ◽  
Author(s):  
G N Askew ◽  
I S Young ◽  
J D Altringham
Keyword(s):  
Soleus Muscle ◽  
Power Output ◽  
Cycle Frequency ◽  
Reduction In Force ◽  
Negative Work ◽  
Loop Shape ◽  
Force Velocity ◽  
Positive Work ◽  
Work Loop

The function of many muscles requires that they perform work. Fatigue of mouse soleus muscle was studied in vitro by subjecting it to repeated work loop cycles. Fatigue resulted in a reduction in force, a slowing of relaxation and in changes in the force-velocity properties of the muscle (indicated by changes in work loop shape). These effects interacted to reduce the positive work and to increase the negative work performed by the muscle, producing a decline in net work. Power output was sustained for longer and more cumulative work was performed with decreasing cycle frequency. However, absolute power output was highest at 5 Hz (the cycle frequency for maximum power output) until power fell below 20% of peak power. As cycle frequency increased, slowing of relaxation had greater effects in reducing the positive work and increasing the negative work performed by the muscle, compared with lower cycle frequencies.

scholarly journals Pharmacological characterization of the relaxant effect induced by adrenomedullin in rat cavernosal smooth muscle

2014 ◽  
Vol 47 (10) ◽  
pp. 876-885
Author(s):  
L.N. Leite ◽  
N.A. Gonzaga ◽  
D.P.C. Tirapelli ◽  
L.F. Tirapelli ◽  
C.R. Tirapelli
Keyword(s):  
Smooth Muscle ◽  
Pharmacological Characterization ◽  
Relaxant Effect

A specific benzodiazepine antagonist CGS 8216 reverses the muscle relaxant effect of diazepam but not that of phenobarbitone

1984 ◽  
Vol 98 (3-4) ◽  
pp. 441-444 ◽  
Author(s):  
Waldemar A. Turski ◽  
Michael Schwartz ◽  
Lechoslaw Turski ◽  
Karl-Heinz Sontag
Keyword(s):  
Muscle Relaxant ◽  
Benzodiazepine Antagonist ◽  
Relaxant Effect ◽  
Cgs 8216

The relaxant effect of nifedipine in human uterine smooth muscle and the BKCa channel

2008 ◽  
Vol 198 (2) ◽  
pp. 237.e1-237.e8 ◽  
Author(s):  
Audrey T. Moynihan ◽  
Terry J. Smith ◽  
John J. Morrison
Keyword(s):  
Smooth Muscle ◽  
Bkca Channel ◽  
Relaxant Effect ◽  
Uterine Smooth Muscle

scholarly journals The effect of lemborexant for insomnia disorder

2021 ◽  
Vol 9 ◽  
pp. 205031212110390
Author(s):  
Hidenobu Suzuki ◽  
Hiroyuki Hibino
Keyword(s):  
Clinical Practice ◽  
Average Dose ◽  
Relaxant Effect ◽  
Athens Insomnia Scale ◽  
Subjective Evaluations ◽  
Duration Of Illness ◽  
Insomnia Disorder ◽  
Efficacy Outcome ◽  
The Mean ◽  
Objective Indicators

Background: Lemborexant has a low dependence potential, less muscle relaxant effect, and less effect on cognitive function. However, there have been no naturalistic reports in Japan clarifying the effect of lemborexant on insomnia disorder. We retrospectively examined the effectiveness of treatment with lemborexant. Methods: Insomnia was assessed using the Athens Insomnia Scale (AIS). Efficacy outcome assessment was the Clinical Global Impressions–Improvement scale (CGI-I). Results: We analyzed 150 patients (male/female = 57/93) in total. The mean subject age and mean duration of illness were 47.8 ± 19.9 years and 4.2 ± 7.2 years, respectively. The average dose of lemborexant was 5.9 ± 2.0 mg. The mean AIS total score was a significant improved (6.6 ± 3.7–3.9 ± 3.3) ( p < 0.01). The mean CGI-I score was 3.2 ± 0.8. The 24-week continuation rates for lemborexant were 86.7%. Conclusion: Similar to the results obtained in previous studies, the CGI-I score, which is one of the objective indicators evaluated by the therapist, and the AIS, which is one of the subjective evaluations of patients, improved as well. The results of this study suggest that lemborexant may be safe and effective in patients with insomnia in real-world clinical practice.

scholarly journals Relaxant effect of quercetin on rabbit isolated bladder smooth muscles contractions

2020 ◽  
Vol 10 (1) ◽  
pp. 61-67
Author(s):  
Hassan Sadraei ◽  
Sabihe Tabesh
Keyword(s):  
Smooth Muscles ◽  
Electrical Field Stimulation ◽  
Negative Control ◽  
Flavonoid Compound ◽  
Drug Candidate ◽  
Control Group ◽  
Organ Bath ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Relaxant Effect

Introduction: Quercetin is a flavonoid compound found in many medicinal plants. Antispasmodic effect of quercetin has been reported in ileum and uterus smooth muscles but not in bladder. Therefore, the objective of this research was to investigate relaxant effect of quercetin in rabbit isolated bladder. Methods: Male rabbit was asphyxiated with carbon dioxide and then sacrificed. The whole bladder was dissected out and placed in oxygenated Tyrode’s solution. Isolated bladder was cut into longitudinal strips and placed in an organ bath for contraction studies. Contractions were induced with KCl (20mM), acetylcholine (5μM) and electrical field stimulation (EFS). Full inhibitory concentration–response curve was constructed for quercetin following addition of above spasmogens. Quercetin was added into the organ bath with 2 fold increments in concentration until maximum response was achieved. Nifedipine was used as positive control group and equivalent volume of quercetin vehicle (water + DMSO) was used as negative control group.Results: Quercetin (4 μg/mL to 640 μg/mL) in a concentration dependent manner inhibited isolated bladder strips contracted by KCl (IC50=159±25 μg/mL), acetylcholine (IC50=43±9.1 μg/mL) and EFS (IC50=38±9.3 μg/mL). In the highest used concentration, quercetin completely removed contractile responses to KCl, acetylcholine and electrical filed stimulation (EFS). Nifedipine totally inhibited KCl response (IC50=115±36 ng/mL) but only partially inhibited acetylcholine and EFS responses. Conclusion: These results confirm the relaxant effect of quercetin on rabbit bladder and if similar effects are seen in human studies, then quercetin would be a suitable drug candidate to be investigated for bladder incontinence.

scholarly journals Influence of muscle length on work from trabecular muscle of frog atrium and ventricle.

1995 ◽  
Vol 198 (10) ◽  
pp. 2221-2227 ◽  
Author(s):  
D A Syme ◽  
R K Josephson
Keyword(s):  
Isometric Force ◽  
Muscle Length ◽  
Work Capacity ◽  
Linear Increase ◽  
Ventricular Muscle ◽  
Work Output ◽  
Loop Technique ◽  
Work Done ◽  
The Relationship ◽  
Work Loop

The work capacity of segments of atrial and ventricular muscle from the frog Rana pipiens was measured as a function of muscle length using the work loop technique. Both the work done during shortening and the work required to re-lengthen the muscle after shortening increased with muscle length. Net work increased with length up to a maximum, beyond which work declined. The optimum sarcomere length for work output was 2.5-2.6 microns for both atrial and ventricular muscle. Isometric force increased with muscle length to lengths well beyond the optimum for work output. Thus, the decline in work at long lengths is not simply a consequence of a reduction in the capacity of heart muscle to generate force. It is proposed that it is the non-linear increase in work required to re-lengthen muscle with increasing muscle length which limits net work output and leads to a maximum in the relationship between net work and muscle length. Extension of the results from muscle strips to intact hearts suggests that the work required to fill the ventricle exceeds that available from atrial muscle at all but rather short ventricular muscle lengths.

scholarly journals Characteristic of the vasorlaxant action of the talatisamine alkaloid and its derivatives

2021 ◽  
Vol 4 (2) ◽  
pp. 01-05
Author(s):  
Mirzayeva Yu.T.
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Channel Blocker ◽  
Aortic Ring ◽  
Diterpenoid Alkaloids ◽  
Relaxant Effect ◽  
Ring Contraction ◽  
Voltage Dependent ◽  
Ca2 Channels ◽  
Isolated Rat

The aim of our research is to study the effect relaxant action of diterpenoid alkaloids talatisamine, 14-O-benzoylthalatisamine and 14-O-acetylthalatisamine was studied using isolated rat aortic rings. Alkaloids significantly and dose-dependently inhibited contraction of the aortic rings caused by high KCl content. At the same time, under these conditions, alkaloids significantly reduced Ca2+-induced contraction of the aortic rings. The relaxing effects of alkaloids are significantly suppressed by verapamil, a potent potentiometer-dependent Ca2+ channel blocker. The alkaloids also significantly reduced norepinephrine-induced aortic ring contraction in normal as well as Ca2+ free Krebs solutions. The data obtained indicate that talatisamine, 14-benzoylthalatisamine and 14-O-acetylthalatisamine exhibit a pronounced relaxant effect in almost the same way in the case of contraction induced by a high content of KCl and norepinephrine. The mechanism of the relaxant action of alkaloids is probably complex and may include suppression of Ca2+influx through voltage-dependent and receptor-driven Ca2+ channels, as well as inhibition of Ca2+transport in the sarcoplasmic reticulum.

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