Studies on a Thrombin-coagulable Protein in Blood Platelets.

Grette, K.; Svennerholm, Lars; Ormerod, John G.; Stenhagen, Einar; Thorell, B.

doi:10.3891/acta.chem.scand.10-1042c

Cited by 7 publications

(9 citation statements)

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“…Thus, a Mg+z-or Ca+?-activated ATPase was identified in isolated synaptic vesicles of rat brain (139,140), and a similar ATPase was isolated from whole brain of the rat and cat (141) and characterized as having properties similar to those of muscle actomyosin and exhibiting an affinity for colchicine binding (142). A contractile protein was also isolated from human platelets (143) which was postulated to play a role in release of histamine and serotonin from these cells. Poisner (144) demonstrated the existence of an actomyosin-like protein in the bovine adrenal medulla, which could participate in the secretory mechanism of catecholamines.…”

Section: When the Gland Is Stimulated Through The Splanchnic Nerve Thmentioning

confidence: 99%

“…In view of the almost universal requirement for calcium in release of secretory products (81 and to be discussed later), Whittaker (94), referring to the possible role of microtubules in secretion, postulated that "if the walls of such tubules were made up of a macromolecule which changed configuration in the presence of calcium ions in such a way as to enlarge the lumen of the tubules, a basis might be provided for the well known essential role of calcium ions in excitation-secretion coupling." Because of the similarities between microtubule protein and actin (104), it is entirely possible that the "macromolecules" postulated by Whittaker (94) may actually constitute the contractile actomyosin isolated from secretory cells (139)(140)(141)(142)(143)(144). Rahwan…”

Section: When the Gland Is Stimulated Through The Splanchnic Nerve Thmentioning

confidence: 99%

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Mechanisms of Stimulus–Secretion Coupling in Adrenal Medulla

Rahwan

Borowitz

1973

Journal of Pharmaceutical Sciences

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Section: When the Gland Is Stimulated Through The Splanchnic Nerve Thmentioning

confidence: 99%

Section: When the Gland Is Stimulated Through The Splanchnic Nerve Thmentioning

confidence: 99%

Mechanisms of Stimulus–Secretion Coupling in Adrenal Medulla

Rahwan

Borowitz

1973

Journal of Pharmaceutical Sciences

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“…Morphologically, thrombin induces platelet swelling, followed by degradation, pseudopod formation, platelet aggregation and fusion [12]. Physiologically, thrombin triggers the release of platelet contents [13]. Thrombin also has a profound influence on platelet metabolism ; it increases the utilization and resynthesis .…”

Section: Cellular Integritymentioning

confidence: 99%

Determination of Platelet Viability

Chao

1971

Vox Sanguinis

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“…Cytochalasin A inhibited aggregation completely at 20,ug/ml (42&M), but cytochalasin B only partially at 100lg/ml (209jzM). Clot retraction was inhibited completely by 4pg/ml of cytochalasin A and by 20,g/ml of cytochalasin B. Cytochalasin A (but not cytochalasin B) reacted with added cysteine, which blocked its effects.Thrombosthenin (platelet actomyosin) was extracted from pig platelets (Grette, 1962; Haslam & Mustard, 1969). The effects of 0.lmM-ATP on the turbidity of stirred suspensions of thrombosthenin in 60mM-KCI at pH7.0 were recorded.…”

mentioning

confidence: 99%

Inhibition of blood platelet function by cytochalasins: effects on thrombosthenin and on glucose metabolism

Haslam

1972

Biochemical Journal

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in the inhibitor molecule was found to have a profound effect on the inhibition constant of the acid. Saturated dicarboxylic acids, with the exception of oxalate, were less inhibitory as the molecular weight increased. A cis effect was observed in the inhibition by unsaturated organic acids; compounds with two cis-carboxyl groups were much more inhibitory than the corresponding trans-isomers. This position effect was investigated quantitatively by measurement of the distances between carboxyl groups in space-filling models of the inhibitors. When these distances were plotted against the inhibition constant of the inhibitor, the degree of inhibition was observed to increase linearly with the increasing proximity of the carboxyl groups. The cytochalasins are mould metabolites that inhibit cytokinesis and cell movement (Carter, 1967). Cytochalasin B can also inhibit platelet aggregation (White, 1971) and clot retraction (Shepro et al., 1970;White, 1971). An attempt has been made to correlate the effects of cytochalasins A and B on platelet function with biochemical changes.Citrated pig platelet-rich plasma at 37°C was used. Platelet aggregation was initiated with ADP (1O0UM) and clotting with bovine thrombin (10N.I.H. units/ ml) in both cases 5min after addition of cytochalasin. Cytochalasin A inhibited aggregation completely at 20,ug/ml (42&M), but cytochalasin B only partially at 100lg/ml (209jzM). Clot retraction was inhibited completely by 4pg/ml of cytochalasin A and by 20,g/ml of cytochalasin B. Cytochalasin A (but not cytochalasin B) reacted with added cysteine, which blocked its effects.Thrombosthenin (platelet actomyosin) was extracted from pig platelets (Grette, 1962; Haslam & Mustard, 1969). The effects of 0.lmM-ATP on the turbidity of stirred suspensions of thrombosthenin in 60mM-KCI at pH7.0 were recorded. In the presence of 4mM-MgC12, ATP cleared the suspension. This effect was inhibited by cyotchalasin A (5-50,ug/ml) but not by cytochalasin B (100lg/ml). With 15mM-MgCl2, ATP caused a rapid superprecipitation which was similarly inhibited by cytochalasin A but not by cytochalasin B. Thrombosthenin was also isolated from platelets that had been incubated with cytochalasin A (4 or 20,ug/ml) for 5 min and then washed. Only with 20,ug/ml were the clearing and superprecipitation phenomena markedly inhibited. Thus only the inhibition of aggregation by cytochalasin A was associated with marked changes in thrombosthenin.Washed rabbit platelets depleted of endogenous substrates rapidly form 14CO2 from [6-14C]glucose (McElroy et al., 1971). In this system cytochalasin A at 4,ug/ml and at 20,tg/ml inhibited "4CO2 formation by about 30 and 70% respectively, whereas these concentrations of cytochalasin B inhibited by 91 and 98 %. Thus the relative effectiveness of cytochalasins A and B was reversed in these experiments.The biological activities of cytochalasin B have been attributed to disruption of contractile microfilaments (Schroeder, 1970; Wessells etal., 1971). The effect ofcytochalasin B on glucose metaboli...

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Studies on a Thrombin-coagulable Protein in Blood Platelets.

Cited by 7 publications

References 0 publications

Mechanisms of Stimulus–Secretion Coupling in Adrenal Medulla

Mechanisms of Stimulus–Secretion Coupling in Adrenal Medulla

Determination of Platelet Viability

Inhibition of blood platelet function by cytochalasins: effects on thrombosthenin and on glucose metabolism

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