Pentobarbital-activated Cl(-) channels in cultured adult and embryonic human DRG neurons

Developmental differences in pentobarbital-activated Cl(-) currents were studied in adult and embryonic human dorsal root ganglia (DRG) neurons using whole-cell patch-clamp recordings. Pentobarbital-induced Cl(-) conductance was significantly greater in adult DRGs (28.4 pS) than in embryonic cells (19.1 pS). Fluctuation analysis of the spectral density plots of Cl(-) channel activation by pentobarbital showed age differences in the length and number of open time constants (adult cells, tau(1), tau(2), tau(3) were 224, 8. 4, 1.5 ms, respectively; embryonic cells tau(1) and tau (2) were 165 and 26.3 ms, respectively). The different kinetic properties of human adult and embryonic DRG Cl(-) channels opened by pentobarbital may reflect the presence of different subunits in the two populations of neurons.