There is an increasing tendency to combine multidisciplinary methods in studying the central nervous systems. One recently developed technique is the combination of electrophysiological and pharmacological investigations by making intracellular recording during extracellular iontophoresis of drugs to study the effects of neurotransmitters on neuronal activity and connections. In this chapter, we describe this technique in detail. We show how: 1. Electrodes are made for this type of study. 2. Drug solutions are prepared for current iontophoresis. 3. A microiontophoresis current generator is used to iontophoretically inject drugs onto a neuron while performing intracellular recording. At the end of this chapter, we provide an example from our recent studies that uses this iontophoretic technique to study effect of counter-intuitive inhibitory effect of blocking GABAA receptors in the control of post-inspiratory activity of the expiratory laryngeal motoneurons.