Histamine formed in stimulated human platelets is cytoplasmic.
The localization of histamine formed by human platelets in response to agonists was evaluated. 87 +/- 5% of the histamine in a suspension of platelets exposed to phorbol-12-myristate-13-acetate (PMA) was associated with the platelet pellet. Incubation of saponin-permeabilized platelets with the intracellular histamine antagonist, N,N-diethyl-2-[4-(phenylmethyl)phenoxy]ethanamine.HCl (DPPE), released 75 +/- 3.9% of the histamine into the supernatant. Under conditions where 90% of platelet serotonin was secreted into the supernatant, the majority (80%) of platelet histamine remained associated with the pellet. The results suggest that histamine synthesized in response to agonists is largely cytoplasmic.
Saxena
S P
SP
Manitoba Institute of Cell Biology, University of Manitoba Winnipeg, Canada.
McNicol
A
A
Brandes
L J
LJ
Becker
A B
AB
Gerrard
J M
JM
D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D005260:Female; D006632:Histamine / Q000096:biosynthesis* / Q000378:metabolism; D006801:Humans; D008297:Male; D010714:Phosphatidylethanolamines / Q000494:pharmacology; D010972:Platelet Activating Factor / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects; D011450:Prostaglandin Endoperoxides, Synthetic / Q000494:pharmacology; D012503:Saponins / Q000494:pharmacology; D012701:Serotonin / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013917:Thrombin / Q000494:pharmacology
D010714:Phosphatidylethanolamines; D010972:Platelet Activating Factor; D011450:Prostaglandin Endoperoxides, Synthetic; D012503:Saponins; C007510:1,2-dipalmitoyl-3-phosphatidylethanolamine; D012701:Serotonin; D006632:Histamine; D013917:Thrombin; D013755:Tetradecanoylphorbol Acetate