In hypoxia, but not normoxia, alpha-tocopherol (vitamin E) acts as an agonist in guinea-pig isolated colon, producing dose-dependent increases in contractile activity. This effect is mimicked by agents, vitamin K1 and phytol, which contain a structural similarity to the phytol side chain of
The pharmacological action of vitamin E on the mechanical activity of isolated guinea pig colonic smooth muscle was examined in normoxic and hypoxic conditions. In hypoxia, but not normoxia, alpha-tocopherol (1-160 microM) evoked rapid concentration-dependent contractions from the colon. This was