Abstract
1. The action of thiamine tetrahydrofurfuryl disulfide (TTFD) on the excised heart of clam (Meretirx meretrix lusoria) was investigated.
2. TTFD displayed a striking postive inotropic action. This action did not appear in Ca-free or Na-free solution, but appeared in K-free solution.
3. TTFD antagonized the negative inotropic action of acetylcholine.
4. These actions of TTFD were closely similar to those of thiamine propyl disulfide and these actions may be ascribed to -N-CHO -C-CH3=C in the structure.
