Chapter 11, Problem 5CCS

Elaine Sawyer, 35, was on her way to the local elementary school with her three children when a bus near her minivan had an accident. the accident on Route 91 occurred. As Mrs. Sawyer swerved to avoid the bus, the right rear corner of her minivan struck the side of the bus, causing the minivan to tip over and slide on its side. Her children were shaken but unhurt. Mrs. Sawyer, however, suffered a severe head injury that caused post-traumatic seizures.

The drugs initially prescribed for her treatment were insufficient to control these seizures. Her doctor additionally prescribed Valium (diazepam), but suggested that she use it only for a month because Valium induces tolerance (loses its effectiveness). After a month of Valium treatment, Mrs. Sawyer no longer had seizures and gradually reduced and eliminated her use of Valium. After being seizure-free for another year, restrictions on her driver’s license were lifted.

Valium actually works postsynaptically to promote binding of GABA to its receptor, thereby enhancing the influx of Cl– ions into the postsynaptic cell (the natural effect produced by GABA). Why would this effect reduce the likelihood that this cell would be able to produce an electrical signal?