The use of GABA(A) receptors expressed in neural precursor cells for cell-based assays

GABA(A) receptors are known targets for certain classes of environmental ne urotoxins and pharmaceutical compounds. Since few neural cell lines express functional GABA(A) receptors, the capacity to rapidly screen for compounds that affect GABA(A) receptor function is presently limited. Previous work has demonstrated that rat neural precursor cells express functional GABA(A) receptors that can be monitored via Call imaging. This study examined GABA (A) receptor subunit expression to determine whether GABA(A) receptor funct ion and its interactions with neurotoxins is preserved after passaging. Neu ral precursor cells isolated from embryonic day 13 rat brain were expanded in serum-free medium containing basic fibroblast growth factor and passaged three times. Reverse transcription-polymerase chain reaction analysis demo nstrated early expression of abundant mRNAs encoding various GABA(A) recept or subunits. Ca2+ imaging showed that the highly proliferating precursor ce lls in passaged cultures maintained expression of functional GABA(A) recept ors. In addition, we showed that trimethylolpropane phosphate, a neurotoxin generated during partial pyrolysis of a synthetic ester turbine engine lub ricant, potently inhibited muscimol (GABA(A) receptor agonist) but not depo larization-induced cytosolic Call increase. The findings of this study sugg est that neural precursor cells may be well suited for the evaluation of ce rtain environmental neurotoxins with convulsant activity. The potential use of neural precursor cells in high-throughput screens for compounds acting on GABA(A) receptors is discussed. (C) 2001 Elsevier Science B.V. All right s reserved.