Thrombin-induced neuropeptide Y secretion from rat platelets.
OBJECTIVE
To study the thrombin-induced secretion of platelet neuropeptide Y (NPY) in rats.


METHODS
The platelet aggregation induced by ADP or thrombin was recorded by an aggregometer. NPY in platelet and plasma was measured by radioimmunoassay. The intracellular free Ca2+ ([Ca2+]i) was measured by Fura-2 fluorescent assay.


RESULTS
Thrombin 0.75 or 2.5 kU L-1 increased [Ca2+]i from 119 +/- 8 nmol L-1 to 530 +/- 60 or 1340 +/- 100 nmol L-1, respectively together with the secretion of platelet NPY. Edetic acid 2 mmol L-1 almost abolished the thrombin-induced increases of [Ca2+]i and reduced the NPY secretion by 56% and 30%, respectively. Neither [Ca2+]i increase nor platelet NPY secretion induced by thrombin was affected by verapamil. The thrombin-induced NPY secretion was inhibited by 55%-70% by indometacin or creatine phosphate plus creatine phosphokinase.


CONCLUSIONS
Thrombin-induced platelet NPY secretion was related to an Ca2+ influx through non-voltage dependent Ca2+ channels and positive feedbacks of arachidonate metabolites or/and released ADP.
Chen
S H
SH
Institute of Vascular Medicine, Third Hospital, Beijing Medical University, China.
Han
Q D
QD
D000244:Adenosine Diphosphate / Q000494:pharmacology; D000818:Animals; D001693:Biological Transport, Active; D001792:Blood Platelets / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D004492:Edetic Acid / Q000494:pharmacology; D008297:Male; D009478:Neuropeptide Y / Q000187:drug effects* / Q000378:metabolism; D010974:Platelet Aggregation / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D013917:Thrombin / Q000494:pharmacology*
D009478:Neuropeptide Y; D000244:Adenosine Diphosphate; D004492:Edetic Acid; D013917:Thrombin; D002118:Calcium