Tm(DOTP)5−: A23Na+ shift agent for perfused rat hearts

Tm(DOTP)5−, the thulium(III) complex of 1,4,7,10-tetraazacyclododecane N,N′,N″,N‴tetra(methylenephosphonate), is introduced as a 23Na1 shift agent for use in discrimination of the NMR resonances of intra- and extracellular 23Na+ ions in perfused rat hearts. The novel shift agent is directly compared to the widely used Dy(TTHA)3- (dysprosium(III) triethylenetetraminehexaacetate). © 1990 Academic Press, Inc.