Constructing a Rapid Solution Exchange System

The detailed study of ligand-gated channels often requires the reproducible, rapid, and temporally precise application of defined concentrations of ligands. There are numerous different systems for ligand application offering trade-offs between cost, ease of use, volume of compound needed, etc. When studying the extremely rapid kinetics of activation and desensitization in ionotropic ligand-gated receptors (iGluR), a prime consideration is how fast solutions can be exchanged. Of the available systems, rapid piezo-driven translation of parallel solutions streams over an outside-out patch offers the fastest and most versatile option, with open tip current rise-times in the 100–300 μs range, and occasionally as fast 20 μs (Bowie and Lange, J Neurosci 22:3392–3403, 2002; Carbone and Plested, Neuron 74:845–857, 2012; Maclean and Bowie, J Physiol 589:5383–5390, 2011; Robert and Howe, J Neurosci 23:847–858, 2003), and pulse durations ≤1 ms (Bowie and Lange, J Neurosci 22:3392–3403, 2002; Carbone and Plested, Neuron 74:845–857, 2012; Robert and Howe, J Neurosci 23:847–858, 2003). Indeed, under ideal conditions agonist applications as short as 100 μs may be possible (Auzmendi et al., PLoS One 7:e42275, 2012). However, from the experimenter’s perspective a “fast” system may also mean a system which rapidly changes test solutions, i.e., how fast can one switch between the various agonists or concentrations bei...
Source: Springer protocols feed by Neuroscience - Category: Neuroscience Source Type: news