| Literature DB >> 10484410 |
M Kimura1, E M Jeanclos, R J Donnelly, J Lytton, J P Reeves, A Aviv.
Abstract
In this report, we have demonstrated that Na+/Ca2+ exchanger activity in a human megakaryocytic cell line (CHRF-288 cells) is K+ dependent, similar to the properties previously described for Na+/Ca2+ exchange activity in human platelets. With the use of RT-PCR techniques and mRNA, the exchanger expressed in CHRF-288 cells was found to be identical to that expressed in human retinal rods. Northern blot analysis of the mRNA for the human retinal rod exchanger in CHRF-288 cells revealed a major transcript at 5.8 kb with two minor bands at 4.9 and 6.8 kb. mRNA for the retinal rod exchanger was also identified in human platelets. Using Ba2+ influx as a measure of Na+/Ca2+ exchange activity in human platelets, we have demonstrated that exchange activity is driven by the transmembrane gradient for K+ as well as that for Na+. We propose that the K+ dependence of the platelet Na+/Ca2+ exchanger could make platelets especially sensitive to daily fluctuations in salt intake.Entities:
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Year: 1999 PMID： 10484410 DOI： 10.1152/ajpheart.1999.277.3.H911
Source DB: PubMed Journal: Am J Physiol ISSN： 0002-9513