Search results for "Muscle Contraction"
showing 10 items of 569 documents
Effect of histamine on the longitudinal and circular muscle of the oestrogen dominated rat uterus.
1993
The response of the longitudinal and circular myometrial strips to histamine was studied in oestrogen-treated rats. Histamine produced a dose-related inhibitory response in KCl-contracted longitudinal and circular uterine strips. Histamine was equipotent in producing the relaxant response but the maximal effect achieved in the longitudinal muscle was higher than the circular one. Ranitidine antagonized the histamine-induced relaxation with a similar dose ratio in both longitudinal and circular strips. Clemizole and reserpine treatment did not produce any modification of the dose-response curve to histamine. In the longitudinal and circular strips which were not preconstricted by KCl, neithe…
Effects of sodium fluoride on the mechanical activity in mouse gastric preparations.
2005
The aim of the present study was to investigate the responses induced by sodium fluoride (NaF) on gastric mechanical activity, using mouse whole-stomach preparations. The mechanical activity was recorded in vitro as changes of intraluminal pressure. In most of the preparations, NaF induced a tetrodotoxin-insensitive biphasic effect characterized by early relaxation followed by slowly developing contractile response. The contraction was dependent on the concentration of NaF, whereas the relaxation was observed at only 10–30 mmol/L NaF. The contractile effect was significantly reduced by nifedipine (an L-type Ca2+channel blocker), ryanodine or ruthenium red (inhibitors of Ca2+release from sar…
Endothelial modulation of 5-hydroxytryptamine-induced contraction in goat cerebral arteries.
1993
Abstract 1. 1. In isolated goat middle cerebral artery segments, 5-hydroxytryptamine (5-HT, 10 −8 −3 × 10 −5 M) caused concentration-dependent contractions, with EC 50 = 2.1 (1.9−2.5) × 10 −7 M and E max = 60 ± 2% of 50 mM KCl-induced contraction. 2. 2. Mechanical removal of endothelium significantly increased the E max (91 ± 8%) and did not change the EC 50 value of 5-HT-elicited contractions. 3. 3. Incubation of unrubbed arteries with the irreversible inhibitor of EDRF, gossypol (10 −5 M), significantly increased the contractile response to 5-HT ( E max = 77 ± 4%). 4. 4. Incubation of unrubbed arteries with the competitive inhibitor of the NO synthesis, N G -nitro - l -arginine (L-NOARG) …
Reliability of isokinetic assessment of shoulder-rotator strength: a systematic review of the effect of position.
2011
Context:Isokinetic assessment of shoulder internal- (IR) and external-rotator (ER) strength is commonly used with many different postures (sitting, standing, or supine) and shoulder positions (frontal or scapular plane with 45° or 90° of abduction).Objective:To conduct a systematic review to determine the influence of position on the intersession reliability of the assessment of IR and ER isokinetic strength, to identify the most reliable position, and to determine which isokinetic variable appears to be most stable in intersession reliability.Evidence Acquisition:A systematic literature search through MEDLINE and Pascal Biomed databases was performed in October 2009. Criteria for inclusion…
Muscle strength and history of heavy manual work among elderly trained women and randomly chosen sample population.
1993
The association between a history of heavy work and muscle strength was studied among 51 physically active women aged 66–85 years trained in sports and 41 women aged 70–81 years selected randomly from the population register. Maximal isometric muscle strength of hand grip, arm flexion, leg extension and trunk flexion and extension were measured using specially constructed dynamometers. The capacity of the abdominal muscles was evaluated by means of a sit-up test. The study included an interview dealing with the subjects' histories of heavy manual employment. The mean histories of heavy work for the trained and untrained women were 24 and 36 years, respectively. The trained women showed sign…
Pre- and Postjunctional Muscarinic Receptors in the Guinea-pig Trachea
1991
ABSTRACT The effects of M2- and Me-selective muscarinic antagonists on electrically evoked [3H]acetylcholine release and muscle contraction were compared in the isolated guinea-pig trachea. The M2-selective antagonists methoctramine and AF-DX 116 were more potent in enhancing the evoked release than in inhibiting the contractile response. As a consequence of the selective blockade of the inhibitory autoreceptors the evoked muscle contractions were enhanced by low concentrations (0.1 μmol/l) of the M2-selective antagonists. The Me-selective antagonists 4-DAMP, UH-AH 37 and pFHHSiD were more potent in reducing the contraction than in facilitating the evoked release. Surprisingly, HHSiD did no…
Relationship between lower limb position and pelvic floor muscle surface electromyography activity in menopausal women: a prospective observational s…
2017
Tomasz Halski,1 Kuba Ptaszkowski,2 Lucyna SÅupska,1 Robert Dymarek,3 MaÅgorzata Paprocka-Borowicz2 1Department of Physiotherapy, Opole Medical School, Opole, 2Department of Clinical Biomechanics and Physiotherapy in Motor System Disorders, 3Department of Nervous System Diseases, Faculty of Health Science, Wroclaw Medical University, Wroclaw, Poland Objectives: In physiotherapeutic practice, special attention is being given to the reciprocal anatomical, physiological, and biomechanical relationship of the pelvis and the structures connected to it. However, the scientific literature shows mainly the theoretical information about their mutual connections. The lack of information about these …
Tensiomyographical responsiveness to peripheral fatigue in quadriceps femoris
2020
Background Fatigue influences athletic performance and can also increase the risk of injury in sports, and most of the methods to evaluate it require an additional voluntary effort. Tensiomyography (TMG), which uses electrical stimulation and a displacement sensor to evaluate muscle contraction properties of one or more muscle bellies, has emerged as a technique that can assess the presence of peripheral and central fatigue without requiring additional voluntary efforts. However, the evaluation of the TMG’s ability to detect fatigue is limited, both at the level of muscle bellies and statistical methods. Thus, the aim of the present study was twofold: (i) to examine and compare the tensiom…
Effects of combined electromyostimulation and gymnastics training in prepubertal girls.
2011
This study investigated the effects of a 6-week combined electromyostimulation (EMS) and gymnastic training program on muscle strength and vertical jump performance of prepubertal gymnasts. Sixteen young women gymnasts (age 12.4 ± 1.2 yrs) participated in this study, with 8 in the EMS group and the remaining 8 as controls. EMS was conducted on knee extensor muscles for 20 minutes 3 times a week during the first 3 weeks and once a week during the last 3 weeks. Gymnasts from both groups underwent similar gymnastics training 5-6 times a week. Isokinetic torque of the knee extensors was determined at different eccentric and concentric angular velocities ranging from -60 to +240° per second. Jum…
Quantitative ultrasonography of muscle: Detection of adaptations to training in elderly women
1996
Abstract Objective: To develop quantitative ultrasonography in studying the adaptation of quadriceps muscle mass and composition to short-term physical training and rehabilitation in elderly women. Design: Randomized control trial. Setting: Measurements in a research laboratory and training in a fitness center and sports hall. Participants: Forty-two women, aged 76 to 78 years, with no indications against intensive physical exercise, randomly assigned to strength ( n = 16), endurance ( n = 15), and control ( n = 11) groups. Twelve subjects from the strength, 12 from the endurance, and 11 from the control group completed the study. Intervention: Supervised physical training 3 times a week fo…