NMDA receptors classification

Although single-channel conductance is a useful diagnostic criterion for the classification of other ionotropic receptors (for instance native NMDA receptors), this does not apply to neuronal nicotinic channels. Conductance levels are not very distinctive, given that even recombinant receptors that should in principle be homogeneous have multiple conductance levels, and these levels overlap considerably for different combinations. In addition, the same combination expressed in different heterologous system can give rise to different... 

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