Amiloride-sensitive potential difference across the blastocoelic wall of early embryos of the newt, Cynops pyrrhogaster

Abstract

1. 1. A potential difference (PD, blastocoelic side positive) across the blastocoelic wall (BW) of embryos of the newt, Cynops pyrrhogaster, appeared at the late morula stage and increased rapidly from the late blastula to initial gastrula stages, reaching a peak of about 60 m V before gastrulation. 2. 2. The increasing PD was reduced to a large extent by amiloride treatment. 3. 3. A PD was also recorded across cultured BW isolated from embryos and was completely abolished by amiloride treatment. 4. 4. These results suggest the appearance of amiloride-sensitive sodium uptake across the BW of newt embryos before gastrulation.