Figure 2.

Activation of human adult muscle nicotinic acetylcholine receptors by ACh. (Left) Openings of single receptors were grouped into clusters bounded by long closings. (Right) Concentration-response curves for adult human nAChRs activated by ACh (□, −70 mV; ⋄, −110 mV; ▵, −150 mV). The overall P _open for each recording was calculated at the indicated concentrations as described in materials and methods. The data are the mean of 2–5 recordings and the solid lines are fits to the Hill equation (Eq. 1). Parameters for these fits are given in Table I.