Figure 1. Increased [Ca²⁺]_i level due to activation of α7, but not non-α7, nAChRs.

A, brief (20–200 ms) duration pressure applications (arrows) of choline (‘Ch’; 10 mm) selectively activated α7-containing nAChRs in a neurone, inducing a rapidly activating and decaying inward current response (bottom trace), and a slower activating and decaying increase in fluorescence due to an increasing [Ca²⁺]_i level (top trace). B, in a different neurone, the activation of non-α7 nAChRs by longer (10 s) pressure applications of ACh (2 mm), along with the α7-selective antagonist MLA (10 nm), induced a more slowly activating inward current response (bottom trace) without any significant change in [Ca²⁺]_i level (top trace).