Disease relevance of Isometric Contraction

• The aneurysmal bulging during isometric contraction also was reduced to a greater degree by reperfusion in the group that received norepinephrine during the ischemic period than it was in the groups undergoing other interventions during ischemia [1].
• Alterations in the physical properties of dermal collagen by streptozotocin-induced diabetes mellitus were investigated in young adult Lewis rats by mounting standardized rings of tail skin on an Instron Universal Testing Apparatus and measuring the thermally induced isometric contraction and stress at rupture of the tissue [2].
• Maximal voluntary isometric contraction (MVIC) is a standardized tool for measuring disease progression in patients with ALS [3].
• Ferret right ventricular hypertrophy is characterized by a decreased and prolonged isometric contraction, associated with altered intracellular calcium (Ca2+) regulation [4].
• The aim of the study was to evaluate the influence of chronic hypobaric hypoxia [43 days at 5050 m above sea level, a.s.l.] on the electrical and mechanical activities of the elbow flexor and knee extensor muscles during sustained maximal isometric contractions [5].

High impact information on Isometric Contraction

• During half-maximal isometric contraction of the tissues with acetylcholine, relaxation responses to isoproterenol, PGE2, and forskolin were separately compared in control (untreated) TSM and tissues incubated for 18 h with IL-1beta (10 ng/ml), TNF-(alpha (100 ng/ml), or IL-2 (200 ng/ml) [6].
• METHODS: Isometric contractions of endothelium-denuded vessel rings were induced cumulatively by methoxamine and relaxations by isoproterenol [7].
• The effect of DHEA appears to involve a large conductance Ca2+-activated potassium channel (BKCa)-dependent stimulatory mechanism, at both function and expression levels (isometric contraction and Western blot), via a redox-dependent pathway [8].
• S100A1 gene transfer resulted in a significant increase of unloaded shortening and isometric contraction in isolated cardiomyocytes and engineered heart tissues, respectively [9].
• Thus, isometric contraction activates eNOS via a Ca2+-independent, tyrosine kinase inhibitor-sensitive pathway and, like shear stress, seems to be an independent determinant of mechanically induced NO formation [10].

Chemical compound and disease context of Isometric Contraction

• We evaluated the actions of phenylephrine on isometric contraction and K+-induced contracture in isolated cat right ventricular muscle from normal hearts and hearts with partial pulmonary artery ligation-induced pressure overload of 5-11 days in duration [11].
• The relationship between tissue oxygenation measured by near-infrared spectroscopy (NIRS) and forearm muscle blood flow (FBF) measured by Doppler ultrasound was tested during isometric contractions at 10 and 30% maximal voluntary contraction (MVC) under conditions of normoxia and hypoxia (14% inspired O2) [12].
• The effects of indomethacin and meclofenamate on active hyperemia following sustained, maximal isometric contractions were studied in free-flowing dog gracilis muscles [13].
• Similarly, neither the maximal responses nor the EC50 values for isometric contractions produced by prostaglandin F2 alpha (PGF2 alpha) (10(-8) to 3 x 10(-5) M) or depolarizing concentrations of K+ (10-100 mM) were altered by hemorrhage (P > 0.05) [14].
• The effects of diltiazem (2.2 X 10(-7) and 2.2 X 10(-6) M) on isometric contraction and K+-induced contracture (Pc) were determined for right ventricular muscles from normal cats and cats with right ventricular systolic hypertension (RVSH) monitored 4-15 days after partial pulmonary artery obstruction [15].

Biological context of Isometric Contraction

• Changes in blood pressure during isometric contractions to fatigue in the cat after brain stem lesions: effects of clonidine [16].
• Elbow flexor muscle fatigue was induced by repetitive voluntary isometric contractions [17].
• AF-DX 116 inhibited carbachol-induced isometric contraction by 15 +/- 1.4%, thus dissociating caldesmon phosphorylation from contraction [18].
• We studied the effects of endogenous prostaglandins and indomethacin (an inhibitor of endogenous prostaglandin production) on isometric contraction of isolated rings of lamb ductus arteriosus from animals of different gestational ages (98 to 103 days and 136 to 147 days; term is 150 days) [19].
• Norepinephrine stimulated simultaneous glycogenolysis and glycogen synthesis, with net glycogen synthesis prevailing over 90 min of isometric contraction [20].

Anatomical context of Isometric Contraction

• Treatment of cells with nocodazole, an inhibitor of microtubule polymerization, stimulated an isometric contraction that reached its peak level within 30 min and was typically 30-45% of the force increase following maximal stimulation with 30% fetal bovine serum [21].
• Skeletal muscle in alloxan diabetes. A comparison of isometric contractions in fast and slow muscle [22].
• Force generation by the myofibroblast depends on the isometric contraction of stress fibers containing alpha-smooth muscle actin, and is mediated through Rho/Rho-kinase [23].
• Lesions of the medial dorsal raphé nuclei or injections of clonidine into the intact medial dorsal raphé nuclei did not affect the pressor response to fatiguing isometric contractions [16].
• Smooth muscle relaxation was expressed as the percent of decrease of norepinephrine-induced isometric contraction [24].

Associations of Isometric Contraction with chemical compounds

• Bay k 8644 increased the force of isometric contractions without producing any change in cyclic AMP levels [25].
• METHODS AND RESULTS: We investigated the influence of levosimendan on isometric contractions and calcium transients (aequorin method) in muscle strips from human hearts with end-stage failing dilated or ischemic cardiomyopathy (n=27) [26].
• The isometric contraction and relaxation of aortic strips produced by norepinephrine and acetylcholine, respectively, were recorded with a force-displacement transducer [27].
• Isometric contractions at 1.2 Lo were not associated with significant changes in histamine-induced increases in [Ca2+] [28].
• The duration of isometric contractions was prolonged by Org 30029, with no change in the duration of the light transients [29].

Gene context of Isometric Contraction

• For functional experiments, the vessels were mounted in organ baths for recordings of isometric contractions in response to endothelin-1, endothelin-3, and the endothelinA-receptor agonist sarafotoxin 6c [30].
• However, the ANG II-induced isometric contraction was reduced (P < 0.05) by leptin (10(-8) mol/liter) [31].
• The effect of potential ECE inhibitors was determined in vitro by measurement of isometric contractions, induced by big ET-1, in isolated rat basilar arteries [32].
• In contrast, Arpp/Ankrd2 was dramatically upregulated only by eccentric contractions, but not by isometric contractions, even though the stress level of the eccentric contractions varied over a three-fold range and overlapped with that of the isometric group [33].
• The relaxant effects of isoproterenol (a nonselective beta-adrenoceptor agonist); ZD7114, BRL37344, and CGP12177A (putative selective beta3-adrenoceptor agonists); and SR59230A (a putative selective beta3-adrenoceptor antagonist) were tested using an isometric contraction technique [34].

Analytical, diagnostic and therapeutic context of Isometric Contraction

• Manual muscle testing, maximum voluntary isometric contraction testing, and muscle mass estimations by dual energy x-ray absorptiometry and urinary creatinine excretion were performed at baseline and at 12 weeks [35].
• Effects of 2-nicotinamidoethyl nitrate (2-NN) on smooth muscle cells of porcine and guinea-pig coronary arteries were investigated by the microelectrode and double sucrose-gap methods and from isometric contractions [36].
• Rather, the enzyme-based cell isolation procedure may partially cleave the thrombin receptor and influence cell responses, since concentrations of SFLLRN which are sub-threshold in enzymatically disaggregated myocytes significantly increase the force of isometric contraction of intact rat papillary muscles [37].
• The purpose of the present study was to confirm the presence of beta3-adrenoceptor subtype in the relaxation of human urinary bladder detrusor tissue by reverse transcription-polymerase chain reaction (PCR); direct sequencing of the PCR product, in situ hybridization; and isometric contraction [34].
• To determine whether cyclooxygenase inhibitors alter parasympathetic control of airway smooth muscle in situ, we pretreated anesthetized dogs with intravenous indomethacin, meclofenamate, or normal saline and measured the isometric contraction of tracheal muscle in response to electrical stimulation of the vagus nerves [38].

References