Gap junctional intercellular communications (GJIC) contributes to neural function in development and differentiation of CNS. In this study, we have investigated the expression of GJIC during the differentiation of neuronal stem cells and 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced neuronal stem cell-derived cells from rat brain. During neuronal stem cell differentiation, expressions of Cx43 and 32 were increased for the duration of 72 hr, however the effect were decreased on the 7d. In the neuronal stem cell-derived cells, pretreatments with p38 MAP kinase inhibitor, SB203580, and MEK inhibitor, PD98059, could protect GJIC against TPA-induced inhibition of GJIC. Our data suggest that GJIC plays an important role during neuronal stem cell differentiation, and ERK1/2 and p38 MAP kinase signaling pathway may be closely related functionally to regulate gap junction in rat neuronal stem cell-derived cells.