Abstract
Nicotine reinforces smoking behavior by activating nicotinic acetylcholine receptors (nAChRs) in the midbrain dopaminergic (DA) reward centers, including the ventral tegmental area (VTA). Although nicotine induces prolonged excitation of the VTA in vivo, the nAChRs on the DA neurons desensitize in seconds. Here, we show that activation of nAChRs on presynaptic terminals in the VTA enhances glutamatergic inputs to DA neurons. Under conditions where the released glutamate can activate NMDA receptors, long-term potentiation (LTP) of the excitatory inputs is induced. Both the short- and the long-term effects of nicotine required activation of presynaptic alpha7 subunit-containing nAChRs. These results can explain the long-term excitation of brain reward areas induced by a brief nicotine exposure. They also show that nicotine alters synaptic function through mechanisms that are linked to learning and memory.
Publication types
-
Research Support, Non-U.S. Gov't
-
Research Support, U.S. Gov't, P.H.S.
MeSH terms
-
Animals
-
Dopamine / metabolism
-
Dose-Response Relationship, Drug
-
Electric Stimulation
-
Excitatory Amino Acid Antagonists / pharmacology
-
Excitatory Postsynaptic Potentials / drug effects*
-
Excitatory Postsynaptic Potentials / physiology
-
In Vitro Techniques
-
Long-Term Potentiation / drug effects*
-
Long-Term Potentiation / physiology
-
Neurons / drug effects
-
Neurons / physiology
-
Nicotine / pharmacology*
-
Nicotinic Agonists / pharmacology*
-
Patch-Clamp Techniques
-
Presynaptic Terminals / drug effects
-
Presynaptic Terminals / metabolism
-
Quinoxalines / pharmacology
-
Rats
-
Rats, Sprague-Dawley
-
Receptors, Nicotinic / metabolism
-
Synaptic Transmission / drug effects
-
Synaptic Transmission / physiology
-
Ventral Tegmental Area / drug effects*
-
gamma-Aminobutyric Acid / metabolism
Substances
-
Excitatory Amino Acid Antagonists
-
Nicotinic Agonists
-
Quinoxalines
-
Receptors, Nicotinic
-
gamma-Aminobutyric Acid
-
FG 9041
-
Nicotine
-
Dopamine