Angiotensin II and Na+/H+ exchange in human blood platelets.
Human blood platelets have a high potency for Na+/H+ exchange activity; they also bear receptors for angiotensin II (Ang II). To explore the effect of Ang II on the exchange, we have used a fluorimetric analysis capable of detecting cytoplasmic changes of 0.01 pH units in platelets, together with an Ang II preparation which has been proven to be effective as a vasoconstrictor. Thrombin and adenosine diphosphate (ADP) affected Na+/H+ exchange, but Ang II did not affect Na+/H+ exchange for a wide range of concentrations and experimental conditions. It is concluded that in contrast to its function in vascular smooth muscle cells, Ang II apparently does not play a role in the regulation of Na+/H+ exchange in human blood platelets.
Argaman
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Department of Biology, Ben Gurion University of the Negev, Beer Sheva, Israel.
Livne
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D000804:Angiotensin II / Q000097:blood*; D001792:Blood Platelets / Q000378:metabolism*; D002352:Carrier Proteins / Q000097:blood*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D017923:Sodium-Hydrogen Exchangers
D002352:Carrier Proteins; D017923:Sodium-Hydrogen Exchangers; D000804:Angiotensin II