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Isoform‐specific regulation of the sodium pump by α‐ and β‐adrenergic agonists in the guinea‐pig ventricle
Author(s) -
Gao J.,
Wymore R.,
Wymore R. T.,
Wang Y.,
McKin D.,
Dixon J. E.,
Mathias R. T.,
Cohen I. S.,
Baldo G. J.
Publication year - 1999
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.1999.0377v.x
Subject(s) - gene isoform , protein kinase c , protein kinase a , guinea pig , ventricle , alpha (finance) , isozyme , medicine , endocrinology , microbiology and biotechnology , chemistry , biology , phosphorylation , biochemistry , enzyme , gene , construct validity , nursing , patient satisfaction
1 Guinea‐pig ventricle was used in the RNase protection assays to determine which α‐isoforms of the Na + ‐K + pumps are present, and ventricular myocytes were used in whole cell patch clamp studies to investigate the actions of α‐ and β‐adrenergic agonists on Na + ‐K + pump current. 2 RNase protection assays showed that two isoforms of the α‐subunit of the Na + ‐K + ‐ATPase are present in guinea‐pig ventricle. The mRNA for the α 1 ‐isoform comprises 82 % of the total pump message, the rest being the α 2 ‐isoform. 3 We have previously shown that β‐adrenergic agonists affect Na + ‐K + pump current ( I p ) through a protein kinase A (PKA)‐dependent pathway. We now show that these β‐effects are targeted to the α 1 ‐isoform of the Na + ‐K + pumps. 4 We have also previously shown that α‐adrenergic agonists increase I p through a protein kinase C (PKC)‐dependent pathway. We now show that these α‐isoform effects are targeted to the α 2 ‐isoform of the Na + ‐K + pumps. 5 These results suggest the effects of adrenergic activation on Na + ‐K + pump activity in the heart can be regionally specific, depending on which α‐isoform of the Na + ‐K + pump is expressed.