Effects of dachengqi decoction and rhubarb on cellular electrical activities in smooth muscle of the guinea-pig taenia coli

The effects of Dachengqi decoction (DCQ) and Rhubarb (Rb) on spontaneous cellular electrical activities of guinea-pig's taenia coli has been studied by intracellular microelectrode technique. DCQ and Rb could both improve depolarization of cell membrane, speed up the burst of slow wave potential (when drug concentration was 1%, P > 0.05; 10% or 20%, P < 0.05), which was dose dependent. At the same concentration, the effects of Rb were more significant than that of DCQ. These results suggested that DCQ and Rb enhanced directly the cellular electrical excitability so as to strengthen the contraction of colon, is one of the mechanisms of these drugs in cellular level on diarrhea action. The ionic basis of the effects might be that DCQ and Rb reduced the K+conductance of cell membrane in rest state.