Abstract
Myocardial cells obtained from fetal mouse heart beat spontaneously and rhythmically in monolayer cultures. Asymmetric disulfide derivatives of thiamine, such as thiamine propyl disulfide (TPD)(5 to 50μM) or thiamine tetrahydrofurfuryl disulfide (TTFD)(5 to 50μM), and a SH reagent, p-chloromercuriphenyl sulfonic acid (PCMPS)(50μW), stopped the spontaneous beating of cultured myocardial cells. The stopping induced by PCMPS was reversed within 19min on addition of SH protective reagent, dithiothreitol. On the other hand, the stopping induced by TPD or TTFD was not reversed within 3h on addition of SH protective reagents, such as dithiothreitol, glutathione (reduced form) or L-cysteine, but the normal beating was recovered within 20h. When TPD or TTFD was added in presence of SH protective reagents on cultured myocardial cells which had been preincubated with the SH protective reagents, the addition of TPD or TTFD did not stop the spontaneous beating.
