Role of β2-containing nicotinic acetylcholine receptors in auditory event-related potentials

Nicotine improves sensory processing in schizophrenic individuals, as measured by changes in auditory event-related potentials (ERPs). Nicotine administration also alters ERPs in mice by increasing the amplitude and gating of the P20 ERP component while decreasing the amplitude of the N40 ERP component. Less is known about the role of specific nicotinic acetylcholine receptor (nAChR) subtypes. In this study, we examined whether nAChRs containing the beta 2 subunit contribute to nicotine's effects on auditory ERPs. We tested the effect of nicotine in wild-type mice and mice lacking the beta 2 nAChR subunit. Mice underwent stereotaxic implantation of stainless steel electrodes located in the CA3 region of the hippocampus, and 50 paired click stimuli were delivered during each drug condition. There was no significant difference in P20 or N40 amplitude or gating between genotypes during the control condition, suggesting that beta 2-containing receptors are not essential for the baseline auditory ERP response. Nicotine increased P20 amplitude and enhanced gating in wild-type and beta 2 knockout mice, but only decreased N40 amplitude in wild-type mice. There was no effect of nicotine on N40 gating in either genotype. beta 2-containing receptors are necessary for nicotine's effects on the N40 component of the mouse auditory ERP. These results suggest that beta 2-containing nAChRs modulate sensory processing and may serve as a therapeutic target in schizophrenic individuals.