Direct action of pentobarbitone in potentiating the responses to GABA of rat dorsal root ganglion neurones in vitro.

Pentobarbitone (PB) was tested for effects on responses to GABA recorded intracellularly in rat dorsal root ganglion neurones. Concentrations of over 1 mM PB elicited small depolarizations, whereas at greater than or equal to 10 microM PB readily potentiated depolarizations and increased membrane conductance evoked by GABA. The GABA antagonists bicuculline and picrotoxin reduced PB-potentiated and equiamplitude control responses to the same degree. Since an action of PB on GABA transport is unlikely in this tissue, the PB effects probably occur at the receptor-ionophore complex.