Spontaneous potentials of embryonic epithelium in urodeles (Cynops orientalis)

The spontaneous potentials (SPs) of nerveless embryonic epithelium of Cynops orientalis were observed by conventional intracellular micro-electrode technique. The amplitude and frequency of SPs of epithelial cells and the course of initiation and decline were recorded. The SPs can occur repeatedly at the stages when the embryonic epithelium is able to conduct excitation. The SP is very similar to the evoked propagatable potential, but has shorter duration. The amplitudes and frequencies of SPs differ in the different embryos and in different epithelial cells in the same embryo. The excitable epithelial cells of the embryo may lose their conductivity when the SPs come to a stable phase both in amplitude and frequency. And the conductivity can recover again after the subsiding of SPs. The SPs can be eliminated by tetrodotoxin (TTX), but they are not affected by the treatment of cobalt chloride.