Addiction Two scientists of the National Institute of Environmental Health Sciences have found evidence for a new role for a specialized neurotransmitter receptor, the nicotinic receptor, in a region of the brain that is thought to be important in learning and memory processes, the hippocampus.
Neurotransmitter receptors are specialized molecules located on the outside of cells.
A neurotransmitter binds to the receptor and, in effect, carries information into the cell. The natural neurotransmitter that ordinarily binds to this nicotinic receptor and carries messages throughout the nervous system and the brain is acetylcholine, a chemical released from one nerve cell to elicit an electrical signal in the next cell within the circuit. The scientists said that this nicotinic receptor, to which nicotine binds, exists in a subset of nerve cells in the hippocampus. This receptor was studied through a technique which records electrical nerve impulses in individual nerve cells. N.C. Dr. Yakel said the identification of this receptor in the hippocampus may have relevance to nicotine's apparent enhancement of memory in some Alzheimer's patients, nicotine addiction, and a rare form of epilepsy.