Abstract：
:Phosphorylation of the regulatory light chain of myosin catalyzed by myosin light-chain kinase (MLCK) is the key reaction in the regulation of actin-myosin interaction in smooth muscle. It is shown that this reaction is of an ordered type, whereby kinase first binds ATP and then the light chain, and following phosphate transfer, the phosphorylated light chain is released before ADP. The MLCK also phosphorylates itself, and this intramolecular autophosphorylation is Ca2+ and calmodulin (CaM) dependent. It has, however, no pronounced effect on the kinase activity or on its affinity for Ca2+ and CaM. With the aim of understanding the cooperativity of MLCK activation, the activity of the kinase was systematically measured as a function of different ligands involved. In these measurements the isolated light chain and intact filamentous myosin, as well as native actomyosin, were used as substrates. The activation of the kinase by Ca2+ was positively cooperative but only at relatively low CaM levels. The activation by CaM (at saturating Ca2+ levels) was also cooperative, even though noncooperative activation would be expected from the established 1:1 binding stoichiometry between CaM and the kinase. This cooperativity was shown to result from time-dependent changes in the MLCK that take place during incubation with Ca2+ and CaM before addition of ATP in phosphorylation assays. As a result, activity of the kinase as a function of its concentration at constant CaM was biphasic: there was optimum activity at a ratio of 1:1 CaM to kinase and almost complete inhibition of the activity at a three- to six-fold excess of the kinase over CaM.(ABSTRACT TRUNCATED AT 250 WORDS)
journal_name
Can J Physiol Pharmacoljournal_title
Canadian journal of physiology and pharmacologyauthors
Sobieszek Adoi
10.1139/y94-197subject
Has Abstractpub_date
1994-11-01 00:00:00pages
1368-76issue
11eissn
0008-4212issn
1205-7541journal_volume
72pub_type
杂志文章abstract：:The issue of bimanual temporal coordination in human subjects is discussed for three selected movement paradigms: (i) simple, symmetric, bimanual finger movements, (ii) bimanual unloading, and (iii) a complex bimanual pull and grasp task. Temporal synchronization was found for all three experiments and was least varia...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章,评审
doi：10.1139/y94-084
更新日期：1994-05-01 00:00:00
abstract：:The effects of U46619, a thromboxane mimic, on cytosolic Ca2+ concentration and platelet aggregation were determined in human platelets. Cytosolic Ca2+ concentration was determined by Quin-2 fluorescence and platelet aggregation quantitated with an aggregometer. Addition of U46619 (1 x 10(-7) M) to the platelet suspen...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y91-088
更新日期：1991-05-01 00:00:00
abstract：:The natural history of the disease of the dilated strain Bio TO-2 of cardiomyopathic hamsters (CMH) is not totally characterized. We investigated its hemodynamic and histomorphometric characteristics at 140, 180, 220, 260, and 300 days of age. Forty CMH and 40 controls were investigated (8 at each stage). Mean arteria...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：
更新日期：2001-04-01 00:00:00
abstract：:We present comparative experimental evidence for the induction of synaptic potentiation and depression in organotypic cultures of hippocampus and in visual cortex in vitro and in vivo. The effects of associative pairings on the efficacy of synaptic transmission are analyzed as a function of the temporal delay between ...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y95-185
更新日期：1995-09-01 00:00:00
abstract：:1. To examine whether different local anesthetics act on different or similar sites in the nerve membrane, the effects of combinations of lipid-soluble anesthetics and tetrodotoxin (TTX) were studied on the compound action potential of the frog sciatic nerve. 2. The nerve-blocking potency of TTX was potentiated 5-fold...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y75-073
更新日期：1975-08-01 00:00:00
abstract：:The heat production (HP), heart rate (HR), respiration rate, rumen motility, and body temperature responses to 2.5-h adrenaline (A) and noradrenaline (NA) intrajugular infusions at 0.00, 0.15, 0.30, 0.60, and 0.90 micrograms.kg-1.min-1 were studied in 10 shorn wethers which had been chronically (3-8 weeks) exposed to ...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y81-150
更新日期：1981-09-01 00:00:00
abstract：:Ethanol (0.3 g/kg) was administered intravenously to adult, male rats at 3 h or at 1 and 3 h after gastric intubation of 7 mg/kg calcium carbimide (CC). For animals administered CC and two ethanol doses, blood ethanol concentration was similar for the two doses; however, blood acetaldehyde concentration was significan...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y84-087
更新日期：1984-05-01 00:00:00
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journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y82-192
更新日期：1982-10-01 00:00:00
abstract：:Natural rodent grooming and other instinctive behavior serves as a natural model of complex movement sequences. Rodent grooming has syntactic (rule-driven) sequences and more random movement patterns. Both incorporate the same movements--only the serial structure differs. Recordings of neural activity in the dorsolate...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y04-061
更新日期：2004-08-01 00:00:00
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journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y85-179
更新日期：1985-09-01 00:00:00
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journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y03-075
更新日期：2003-08-01 00:00:00
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journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y08-072
更新日期：2008-10-01 00:00:00
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journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章,评审
doi：10.1139/cjpp-2016-0597
更新日期：2017-10-01 00:00:00
abstract：:Techniques to dissociate different sites or stores important for Ca2+ entry or release in smooth muscle include washouts of 45Ca in cold La3+ -substituted solutions. Scatchard-coordinate plots of Ca2+ uptake, substitution of Sr2+ for Ca2+, and both desaturation and rate coefficient plots. Rabbit aortic smooth muscle i...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章,评审
doi：10.1139/y87-119
更新日期：1987-04-01 00:00:00
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journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y83-133
更新日期：1983-08-01 00:00:00
abstract：:The mechanisms responsible for microbially induced epithelial apoptosis and increased intestinal permeability remain unclear. This study assessed whether purified bacterial lipopolysaccharide (LPS) increases epithelial apoptosis and permeability and whether these changes are dependent on caspase-3 activation. In nontu...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y06-056
更新日期：2006-10-01 00:00:00
abstract：:Some current questions regarding muscle afferent receptors are discussed. These include the significance of variable distribution patterns of muscle spindles in different muscles and of differences in intrinsic spindle morphology. The significance of the very large and variable population of small myelinated afferent ...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y81-100
更新日期：1981-07-01 00:00:00
abstract：:Endothelin-1 (ET-1) is a potent vasoactive peptide that exerts hypertrophic, migratory, and mitogenic effects in vascular smooth muscle cells. ET-1-induced activation of several signaling events has been shown to mediate the cellular effects of ET-1. In the past several years, transactivation of growth factor receptor...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章,评审
doi：10.1139/y10-030
更新日期：2010-05-01 00:00:00
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journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y81-053
更新日期：1981-04-01 00:00:00
abstract：:The inotropic response induced by beta-adrenergic and H1 histaminergic receptor stimulation was characterized in guinea pig left atria by obtaining dose-response relationships for isoproterenol and histamine under various experimental conditions. Conditions (hypothermia, high frequencies of stimulation, and large extr...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y78-147
更新日期：1978-12-01 00:00:00
abstract：:Luminal nutrition is important for the maintenance of small intestinal structure and function. The equilibrium between crypt cell production and villous cell loss in the mucosal epithelium of the small intestine is altered under certain conditions such as after a small bowel resection. Immediately after resection, the...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章,评审
doi：10.1139/y90-095
更新日期：1990-05-01 00:00:00
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journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y85-188
更新日期：1985-09-01 00:00:00
abstract：:The inhibition of hepatic microsomal aryl hydrocarbon hydroxylase (AHH) activity by SKF 525-A in vitro was studied in hepatic microsomes from rats of varying age, sex hormone status, and drug treatment. The concentration of SKF 525-A required to produce a 50% inhibition of AHH activity, the IC50, was determined for th...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y82-156
更新日期：1982-08-01 00:00:00
abstract：:The twitch-potentiating effects of opioids in the frog's skeletal muscle which are naloxone resistant and nonstereospecific were further studied. The rapid kinetics of the onset and of the offset (following washout) of the opioid effect indicates that the site for this action is the surface membrane of the muscle fibr...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y86-168
更新日期：1986-07-01 00:00:00
abstract：:The aim of this study was to elucidate the variables of gastroduodenal motility determining gastric emptying. For this purpose the effects of exogenous cholecystokinin, secretin, and gastric inhibitory polypeptide on motility and gastric emptying were studied during a meal. Motility was measured with extraluminal stra...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y87-050
更新日期：1987-03-01 00:00:00
abstract：:Our objective was to determine the effects of a clenbuterol (CB) treatment orally administered (2 mg per kg) to rats submitted to 14 days of hindlimb unloading (HU). The morphological and the contractile properties as well as the myosin heavy chain isoforms contained in each fiber type were determined in whole soleus ...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y04-034
更新日期：2004-05-01 00:00:00
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journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y05-067
更新日期：2005-08-01 00:00:00
abstract：:Aortas were removed from six mature lambs and four sheep and pressure fixed at 100 and 120 mmHg pressure (1 mmHg = 133.322 Pa), respectively, in 10% buffered formalin. The numbers of elastin layers were counted from cross sections at different distances down the aorta, from the distal arch to the iliac bifurcation, an...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/y83-016
更新日期：1983-02-01 00:00:00
abstract：:Sarcoplasmic reticulum (SR) calcium handling in diaphragm was compared between mdx mice (7-8 weeks old) and age-matched controls. The total SR Ca2+ load was released from the SR by rapidly cooling muscle bundles from 22 to -1 degree C. The plateau amplitude of the rapid cooling contracture (RCC) was considered as an i...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：10.1139/cjpp-76-12-1161
更新日期：1998-12-01 00:00:00
abstract：:Using conventional intracellular microelectrode techniques, the membrane potential (Em) of vascular smooth muscle cells in isolated segments of thoracic rat aorta was measured. The influence of exogenous and of endothelium-derived nitric oxide on the Em was assessed, and the involvement of glibenclamide-sensitive chan...
journal_title：Canadian journal of physiology and pharmacology
pub_type： 杂志文章
doi：
更新日期：1997-12-01 00:00:00
