Naftopidil inhibits 5-hydroxytryptamine-induced platelet aggregation and 5-hydroxytryptamine uptake in platelets of healthy volunteers

1994 ◽  
Vol 46 (3) ◽  
Author(s):  
R. Kirsten ◽  
M. Breidert ◽  
K. Nelson ◽  
A. Heine ◽  
S. Rosenkranz ◽  
...  
1984 ◽  
Vol 51 (01) ◽  
pp. 037-041 ◽  
Author(s):  
K M Weerasinghe ◽  
M F Scully ◽  
V V Kakkar

SummaryCollagen mediated platelet aggregation caused -5.6 ± 6.7% inhibition and +39.1 ± 15.2% potentiation of prekallikrein activation in plasma from normal healthy volunteers between 20–40 and 50–65 years of age, respectively (n = 15, p <0.01). The amouns of platelet factor-four (PF4) released in the two groups were not significantly different. Collagen treatment in the presence of indomethacin caused +11.5 ± 3.6% and +59.6 ± 19.5% potentiation in the 20–40 and 50–65 age groups respectively (p <0.02). Adrenaline mediated platelet aggregation caused -55.2 ± 7.1% and -35.2 ± 8.3% inhibition in the 20–40 and 50–65 age groups, respectively. Collagen treatment of platelet-deficient-plasma and platelet-rich-plasma in EDTA also caused potentiation of prekallikrein activation.The results indicate that the observed degree of prekallikrein activation after platelet aggregation is a net result of the inhibitory effect of PF4 and the potentiatory effect of activated platelets. The potentiatory effect was greater after collagen treatment as compared to adrenaline treatment, and in the 50–65 age group as compared to the 20–40 age group.


2018 ◽  
Vol 46 (12) ◽  
pp. 5074-5082 ◽  
Author(s):  
Thomas Kander ◽  
Erik Lindblom ◽  
Ulf Schött

Objective This study aimed to evaluate the dose-response effects of supplemental omega-3 fatty acids on platelet function in healthy volunteers. Methods Twelve healthy volunteers ingested a normal supplemental dose of 1260 mg omega-3 fatty acids daily for 5 days, followed by a high dose of 2520 mg daily for another 5 days. Multiple electrode aggregometry (MEA) with four different agonists was used to measure platelet aggregation before and after the normal- and high-dose regimes. In vitro spiking using physiological doses of omega-3 fatty acids was also performed to determine whether MEA is capable of detecting a platelet-inhibiting effect due to omega-3 fatty acids. Results There were no differences in platelet aggregation measured by the MEA assay in healthy volunteers after intake of either the normal or high dose of omega-3 fatty acids. In the in vitro experiment, a platelet-inhibiting effect of omega-3 fatty acids was shown by an arachidonic acid agonist in MEA . Conclusions Supplemental omega-3 fatty acids do not evoke their positive health effects through inhibition of platelet aggregation measurable with MEA.


2000 ◽  
Vol 83 (02) ◽  
pp. 309-315 ◽  
Author(s):  
Axel Herr ◽  
Johann Motsch ◽  
Alexandra Holzmann ◽  
Jörg Weimann ◽  
Friedemann Taut ◽  
...  

SummaryThe platelet inhibitory effect of 0-40 ppm inhaled nitric oxide (NO) was investigated in healthy men and women. In both groups, ADPand collagen-induced platelet aggregation was significantly inhibited 20 (T20) and 40 min (T40) after the beginning of inhalation of 5, 10, and 40 ppm. Moreover, in both men and women, the in vitro bleeding time was significantly prolonged at T20 and T40 during inhalation of 40 ppm. Inhalation of NO also inhibited P-selectin expression at 5, 10, and 40 ppm and fibrinogen binding to the GPIIb/IIIa-receptor at 40 ppm. In conclusion, in healthy volunteers, the platelet inhibitory effect of inhaled NO was not dose-related, since it was significant at 5 and 10 ppm but did not increase during the administration of higher NO concentrations. In addition, gender-related differences were only observed in ADP-induced platelet aggregation at 10 ppm and in bleeding time prolongation at 40 ppm.


Platelets ◽  
2011 ◽  
Vol 22 (4) ◽  
pp. 243-251 ◽  
Author(s):  
V.V. Yakushkin ◽  
I.T. Zyuryaev ◽  
S.G. Khaspekova ◽  
O.V. Sirotkina ◽  
M.YA. Ruda ◽  
...  

Platelets ◽  
2003 ◽  
Vol 14 (5) ◽  
pp. 325-327 ◽  
Author(s):  
Andrew J. Innes ◽  
Gwen Kennedy ◽  
Margaret McLaren ◽  
Anne J. Bancroft ◽  
Jill J. F. Belch

1981 ◽  
Vol 9 (1) ◽  
pp. 12-17 ◽  
Author(s):  
A Vittoria ◽  
F Laghi Pasini ◽  
G L Messa ◽  
T Di Perri ◽  
G Corvi ◽  
...  

A complete crossover trial was undertaken in six healthy volunteers to gain information on dose-effect responses to indobufen by assessing the intensity and duration of the effect of 3 single oral doses of the drug on platelet aggregation induced by threshold concentration of ADP and by 3 added doses of collagen. The results of the study confirm that the activity is dose-related and is reversible since 24 hours after administration it has practically disappeared. The effect of the same dose of indobufen differed significantly according to the amount of collagen added to plasma, whereas increasing doses of indobufen provoked a significantly more marked effect when the amount of inducer employed was the same.


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