Recordings of cultured neurons and synaptic activity using patch-clamp chips

Planar patch-clamp chip technology has been developed to enhance the assessment of novel compounds for therapeutic efficacy and safety. However, this technology has been limited to recording ion channels expressed in isolated suspended cells, making the study of ion channel function in synaptic transmission impractical. Recently, we developed single- and dual-recording site planar patch-clamp chips and demonstrated their capacity to record ion channel activity from neurons established in culture. Such capacity provides the opportunity to record from synaptically connected neurons cultured on-chip. In this study we reconstructed, on-chip, a simple synaptic circuit between cultured pre-synaptic visceral dorsal 4 neurons and post-synaptic left pedal dorsal 1 neurons isolated from the mollusk Lymnaea stagnalis. Here we report the first planar patch-clamp chip recordings of synaptic phenomena from these paired neurons and pharmacologically demonstrate the cholinergic nature of this synapse. We also report simultaneous dual-site recordings from paired neurons, and demonstrate dedicated cytoplasmic perfusion of individual neurons via on-chip subterranean microfluidics. This is the first application of planar patch-clamp technology to examine synaptic communication.