A plasmatic factor may cause platelet activation in acute ischemic stroke.
To study the pathogenesis of platelet activation in ischemic stroke, ionized calcium ([Cai2+]) was measured in aequorin-loaded gel-filtered platelets in the basal and stimulated state. Basal [Cai2+] was increased in stroke patients maximally 36-72 hours after onset. The increase in [Cai2+] after stimulation with thrombin, collagen, and platelet-activating factor were also greater in stroke patients, but the profiles of these [Cai2+] changes were parallel to control. Cross incubation of control platelets with plasma from stroke patients resulted in raised basal [Cai2+] and caused the release of serotonin from platelets. These results indicate that the higher platelet basal [Cai2+] in stroke patients represents a lowered threshold for activation and that this may be due to a plasmatic factor rather than a primary platelet defect.
Joseph
R
R
Department of Neurology, Henry Ford Hospital, Detroit, Michigan.
Welch
K M
KM
Oster
S B
SB
Grunfeld
S
S
D'Andrea
G
G
D000328:Adult; D000367:Age Factors; D000368:Aged; D001792:Blood Platelets / Q000502:physiology*; D002118:Calcium / Q000097:blood; D002561:Cerebrovascular Disorders / Q000097:blood*; D003094:Collagen / Q000494:pharmacology; D006801:Humans; D066298:In Vitro Techniques; D008875:Middle Aged; D015539:Platelet Activation; D012701:Serotonin / Q000378:metabolism; D012737:Sex Factors
D012701:Serotonin; D003094:Collagen; D002118:Calcium