Expression of GABAA receptor polypeptides in clonal rat cell lines.

The neuronal-like cell lines, B35, B65, B103, and B104, previously reported to possess high affinity GABA binding, were analyzed for various cellular properties. They possessed peripheral but lacked central benzodiazepine binding. Only B65 cells possessed [3H-]muscimol binding; none bound [35S]TBPS. None of the cells exhibited GABA-stimulated chloride conductance with patch clamp recordings. By Western blots the cells possessed alpha subunits. Northern blot and polymerase chain reaction analysis showed that out of alpha 1, alpha 4, beta 1 and gamma 2 subunits, only alpha 1 subunit mRNA was present. Thus, GABAA-receptor binding without associated central benzodiazepine receptor sites and without functional chloride channels appears to result from expression of an incomplete subunit composition.