Characterizing functional α6β2 nicotinic acetylcholine receptors in vitro: Mutant β2 subunits improve membrane expression, and fluorescent proteins reveal responsive cells | Academic Article individual record
abstract

α6* nicotinic acetylcholine receptors (nAChRs) are highly expressed in mesostriatal and nigrostriatal dopaminergic systems, and participate in motor control, reward, and learning and memory. In vitro functional expression of α6* nAChRs is essential for full pharmacological characterization of these receptors and for drug screening, but has been challenging. We expressed eGFP-tagged-α6 and β2 nAChR subunits in Neuro-2a cells, leading to functional channels. Inward currents were elicited with 300 μM ACh in 26% (5/19) of cells with evenly expressed α6-eGFP in cytoplasm and periphery. We dramatically increased chances of detecting functional α6-eGFPβ2 nAChRs by (i) introducing two endoplasmic reticulum (ER) export-enhancing mutations into β2 subunits, and (ii) choosing cells with abundant Sec24D-mCherry-labeled ER exit sites. Both manipulations also modestly increased α6-eGFPβ2 nAChR current amplitude. α6-eGFPβ2 nAChRs were also activated by nicotine and by TC-2403. The α6-eGFPβ2 currents were desensitized by 1μM nicotine, blocked by α-conotoxin MII, partially inhibited by dihydro-β-erythroidine, and potentiated by extracellular Ca(2+). Single-channel recordings showed that α6-eGFPβ2 nAChRs had similar single-channel conductance to, but longer open time than, α4-eGFPβ2 nAChRs. These methods provide avenues for developing cell lines expressing subtypes of α6* nAChRs for both pharmacological study and drug screening.

author list (cited authors)
Xiao, C., Srinivasan, R., Drenan, R. M., Mackey, E., McIntosh, J. M., & Lester, H. A.
publication date
2011
publisher
Elsevier BV Publisher
published in
keywords
  • Alpha 6
  • Neuro2a Cell
  • Beta 2
  • Endoplasmic Reticulum Exit Sites
  • Nicotinic Acetylcholine Receptor
  • Fluorescent Protein
citation count

29