Figure 2. Effects of nicotinic and P2 purinoceptor blockers on spike frequency of a co-cultured petrosal neurone that showed spontaneous rhythmic discharge.

The neurone was adjacent to a large type 1 cell cluster (≈40 cells). Spontaneous spike frequency was reversibly inhibited in a dose-dependent manner by the P2 purinoceptor blocker suramin (Aa), and by the nicotinic blocker mecamylamine (Ab), at the indicated concentrations. In Ac, combined application of suramin (50 μM) and mecamylamine (1 μM) abolished the spike discharge and the effect was reversible. The time course of the effects of the drugs on spike frequency is shown for this cell in B; spike frequency was calculated from 5 s segments of the continuous record. Resting potential -62 mV.