A 13C magnetic resonance study of embryonic chick aorta

13C nmr spectra of defatted aorta, obtained from chick embryos, ranging in age from 13 to 20 days, showed that linewidths were independent of the age of the embryo, this, in spite of the fact that crosslinking increases with age. As expected the dipolar decoupled spectrum of defatted aorta had a larger C-H signal intensity than the scalar decoupled spectrum, since collagen in the sample contributes signal intensity only in the former case. Significantly, the dipolar decoupled spectrum of autoclaved aorta also had a larger C-H signal intensity. This result indicates that ca. 30% of the carbons in the tissue, swollen by 0.15 M NaCl, has restricted motion at 37 degrees. Preliminary data indicate that tissue culture techniques can be used to enrich specific amino acids in chick aorta with 13C, thereby affording a means to study possible differences in molecular structure of the chemically distinct regions in elastin.