The main advantage of recording from recombinant receptors lies in the well-defined subunit composition of the receptors which we want to study. It is also easy to introduce mutations into these receptors, measure them and compare them to wild type receptors. The receptor composition is stable over time and can’t be affected by external influences.

Patch clamp recording from recombinant receptors is similar to that described in section Patch clamp recording. To be able to study fast processes of binding and unbinding of agonists, internal transition of the receptors to the non-conducting states (desensitization) and modulation characteristics of the receptors by drugs, we must use an application system which allows exchanging the test solution around the cell faster than the studied process (Fig. A)

The configuration of the patch-clamp measurement with fast application system is shown in the Fig. B. This system allows changing the solutions in approximately 10 ms.

Fig. A Patch-clamp recordings with fast application system.

Fig. B Current response of NMDA receptor NR1-1a/NR2B expressed in HEK cells activated by 1 mM of glutamate and co-application of glutamate with 150 μM inhibitory neurosteroid 5β-pregnan-20-on 3α-yl-sulfate. The main characteristics of current response are indicated.