Pharmacology of spontaneous synaptic currents mediated by neuronal nicotinic acetylcholine receptors.A, Spontaneous synaptic currents recorded from a P22 layer 5 pyramidal neuron in the presence of GABA and glutamate receptor antagonists. B, These events were abolished by the selective nicotinic acetylcholine receptor antagonist DHβE (100 μm). C, Cumulative amplitude distribution for cholinergic events recorded from the cell shown inB. Addition of DHβE shifted the distribution to the left (p < 0.001, one-way ANOVA; number of events analyzed = 66 and 13), indicating that the few remaining events represent a different type of input. Remaining synaptic activity in the presence of DHβE was abolished by addition of the 5-HT3 receptor antagonist ICS 205-930. D, Cumulative frequency distribution of cholinergic events. Addition of DHβE shifted the distribution toward longer interevent intervals (p < 0.001, one-way ANOVA; number of events analyzed = 66 and 11). PTX, Picrotoxin.
