In addition to alterations in glutamatergic signaling, there is ample evidence showing other neurotransmitter systems, such as the cholinergic and dopaminergic, play a vital role in modulating the induction, duration, and magnitude of synaptic plasticity (Otani, 2003; Drever et al., 2011). ACh acts on a variety of different pre- and post-synaptic receptors throughout the brain resulting in profoundly different outcomes depending on receptor location and subunit composition (Alkondon and Albuquerque, 2004). Thus far, most studies have implicated the involvement of G-protein coupled muscarinic receptors in mediating these synaptic changes; however, more recently nAChRs have come under investigation to understand their part in these processes. In this section, the role of nAChRs in the modulation of neurotransmission and drug-induced plasticity will be discussed for the brain loci that have been implicated to be important for the development of nicotine and ethanol addiction.
