GABAA (a1b2g2) - "Rapid agonist applications in precise intervals (GABAA) "
Patchliner application note: (1.5 MB)
HEK-cells expressing GABAA-receptors were investigated with the Patchliner using a stacked application approach for rapid administration of compounds to the patch-clamped cells. The GABAA receptor family is the most important class of inhibitory ion channels involved in synaptic transmission, and are selectively permeable to monovalent anions. They constitute an important therapeutic area for drugs affecting anxiety, sleep and muscle relaxation. As with most ligand gated ion channels, GABAA exhibit receptor desensitization, which is a common phenomenon for ligand gated ion channels. Desensitization can be either exposure time dependent or concentration dependent, or both. Desensitization and recovery kinetics varies from milliseconds to tens of minutes, all depending on receptor type and subunit composition. For rapidly desensitizing ion channels, it is important that compound application is fast, so that the entire ion channel population is exposed to maximum concentration before entering the desensitized state. Exposure time and application intervals are important factors affecting desensitization and recovery from desensitization, to minimize deletrious effects or receptor desensitization. In the experiments presented here, compounds were added to the cells with accurate timing. In addition, a method for brief compound application was developed, allowing 1 s pulses of compound to the patch clamped cells. In this way, receptor desensitization can be minimized, and because of the timed exposures, effects of desensitization.