Abstract
Nicotine is an agonist at one of the two known subtypes of acetylcholine receptor. The nicotinic acetylcholine receptor (nAChR) is composed of five subunits that confer kinetic responses of the receptor when agonist is bound. The most common constellations of subunits found within the human brain are the heteromeric a4Β2 and the homomeric a7. nAChRs are most commonly thought of as being present in presynaptic membranes of excitatory or inhibitory terminals. However, nAChRs, which exhibit a postsynaptic location, are also present in the brain and can be found on somata, dendrites, and axons. nAChRs are found within neuronal circuits involved in conferring saliency to internal and environmental stimuli, which include drugs of abuse. Stimulation of pre- and postsynaptic nAChRs by nicotine in this circuitry results in large rises in dopamine, which underlies the reinforcing property of this drug. In addition to direct stimulation of these reinforcing circuits, nicotine exposure induces concurrent activation of nAChRs in neuronal groups that send excitatory projections to this circuitry, thereby amplifying the neuronal stimulation engendered by this drug. Thus, exposure to nicotine can alter neuronal excitability within addiction-related circuits via a multiplicity of anatomical localizations of nAChRs and via the presence of nAChRs within the synapse at pre- and/or postsynaptic sites.
| Original language | English |
|---|---|
| Title of host publication | The Neurobiology of Nicotine |
| Editors | Victor Preedy |
| Publisher | Elsevier |
| Publication date | 1 Jan 2019 |
| ISBN (Print) | 9780128130353 |
| ISBN (Electronic) | 9780128130360 |
| Publication status | Published - 1 Jan 2019 |