Differences in platelet calcium regulation between African Americans and Caucasians: implications for the predisposition of African Americans to essential hypertension.
OBJECTIVE
To study differences in cytosolic free calcium regulation between African Americans and Caucasians, using platelets as a model for studying cellular physiology.


METHODS
Platelet calcium regulation in apparently healthy African American and Caucasian males was examined.


METHODS
Using fura-2, calcium influx and cytosolic calcium extrusion were monitored after treatment with thapsigargin, an inhibitor of the Ca-ATPase in the dense tubular membrane system.


RESULTS
Compared with Caucasians, platelets from African Americans demonstrated a higher calcium influx into the cytosol (from the external medium and dense tubular membrane system), as well as enhanced calcium extrusion from the cytosol.


CONCLUSIONS
Such findings indicate that platelets from African Americans have increased intracellular calcium stores or increased cellular calcium turnover, or both. If these racial differences involve other cells, such as vascular smooth muscle cells, they could underlie the predisposition of African Americans to essential hypertension.
Kimura
M
M
Hypertension Research Center, University of Medicine and Dentistry of New Jersey, New Jersey Medical School, Newark 07103-2714.
Cho
J H
JH
Lasker
N
N
Aviv
A
A
D000328:Adult; D044383:Black People; D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000097:blood*; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000097:blood; D002352:Carrier Proteins / Q000097:blood; D003600:Cytosol / Q000378:metabolism; D004533:Egtazic Acid / Q000494:pharmacology; D016257:Fura-2; D006801:Humans; D006973:Hypertension / Q000209:etiology*; D066298:In Vitro Techniques; D017136:Ion Transport; D008055:Lipids / Q000097:blood; D008297:Male; D012964:Sodium / Q000097:blood; D019831:Sodium-Calcium Exchanger; D013729:Terpenes / Q000494:pharmacology; D019284:Thapsigargin; D044465:White People; D001741:Black or African American
D002352:Carrier Proteins; D008055:Lipids; D019831:Sodium-Calcium Exchanger; D013729:Terpenes; D004533:Egtazic Acid; D019284:Thapsigargin; D012964:Sodium; D000252:Calcium-Transporting ATPases; D002118:Calcium; D016257:Fura-2