Basic NeuroscienceShort communicationCombining pharmacology and whole-cell patch recording from CNS neurons, in vivo

Whole-cell patch neurophysiology and pharmacological manipulations have provided unprecedented insight into the functions of central neurons, but their combined use has been largely restricted to in vitro preparations. We describe a method for performing whole-cell patch recording and focal application of pharmacological agents in vivo. A key feature of this technique involves iontophoresis of glutamate to establish proximity of drug and recording pipettes. We show data from iontophoresis of glutamate during extracellular and whole-cell recordings made in vivo from auditory neurons in the midbrain of the leopard frog, Rana pipiens, and the effects of blocking GABAA receptors while making a whole-cell recording. This methodology should accelerate our understanding of the roles of particular neurotransmitter systems in normal and pathological conditions, and facilitate investigation of the in vivo effects of drugs and the mechanisms underlying computations.

► Proof of concept: whole-cell patch recording with focal application of drugs deep in the brain in vivo is demonstrated. ► Iontophoresis of glutamate is a key methodological step for effectively positioning drug and recording pipettes. ► Whole-cell recordings from an auditory neuron before and after focally blocking GABAA receptors, in vivo, are shown. ► This methodology permits a new level of inquiry into the mechanisms underlying neuronal computations.