[Physiological interaction between acetylcholine and dopamine in the striatum].
The breakdown of the balance between acetylcholine and dopamine in the striatum is known to cause a variety of neurological diseases. Physiologically, the association between sensory cues and reward during behavioral learning gradually forms a conditional pause response in the firing of the tonically active cholinergic interneurons in the striatum. Simultaneous recordings of striatal cholinergic interneurons and midbrain dopaminergic neurons during the task revealed that the pause response was well synchronized with the increase in the firing frequency of the dopaminergic neurons. Recent studies have indicated that the content of released dopamine is proportional to the firing frequency of the dopaminergic neurons unless the nicotinic receptors are activated, but it remains unaltered if the receptors are bound by acetylcholine. Therefore, dopamine release would be dramatically increased during the pause response of the cholinergic neurons. The pause response is composed of an initial depolarization phase, a pause phase, and a rebound facilitation phase. Dopamine D5 receptor-dependent long-term potentiation underlies the initial depolarization phase, which causes the ensuing pause phase. The termination of the pause is further delayed by suppression of Ih and sodium channels through dopamine D2 receptor activation. This facilitates the synaptic efficacy of the striatal medium spiny projection neurons, which enables the execution of action commands with an improved signal-to-noise ratio.
Aosaki
Toshihiko
T
Tokyo Metropolitan Institute of Gerontology, Research Team for Functional Genomics, 35-2 Sakae-cho, Itabashi-ku, Tokyo 173-0015, Japan.
Miura
Masami
M
Masuda
Masao
M
D000109:Acetylcholine / Q000502:physiology*; D003342:Corpus Striatum / Q000502:physiology*; D004298:Dopamine / Q000502:physiology*; D006801:Humans; D007858:Learning; D009474:Neurons / Q000502:physiology; D011954:Receptors, Dopamine / Q000502:physiology; D011976:Receptors, Muscarinic; D011978:Receptors, Nicotinic
D011954:Receptors, Dopamine; D011976:Receptors, Muscarinic; D011978:Receptors, Nicotinic; D000109:Acetylcholine; D004298:Dopamine