title: Regulation of dopaminergic neuron firing by heterogeneous dopamine autoreceptors in the substantia nigra pars compacta.
abstract: Dopamine (DA) receptors generate many cellular signals and play various roles in locomotion, motivation, hormone production, and drug abuse. According to the location and expression types of the receptors in the brain, DA signals act in either stimulatory or inhibitory manners. Although DA autoreceptors in the substantia nigra pars compacta are known to regulate firing activity, the exact expression patterns and roles of DA autoreceptor types on the firing activity are highly debated. Therefore, we performed individual correlation studies between firing activity and receptor expression patterns using acutely isolated rat substantia nigra pars compacta DA neurons. When we performed single-cell RT-PCR experiments, D(1), D(2)S, D(2)L, D(3), and D(5) receptor mRNA were heterogeneously expressed in the order of D(2)L > D(2)S > D(3) > D(5) > D(1). Stimulation of D(2) receptors with quinpirole suppressed spontaneous firing similarly among all neurons expressing mRNA solely for D(2)S, D(2)L, or D(3) receptors. However, quinpirole most strongly suppressed spontaneous firing in the neurons expressing mRNA for both D(2) and D(3) receptors. These data suggest that D(2) S, D(2)L, and D(3) receptors are able to equally suppress firing activity, but that D(2) and D(3) receptors synergistically suppress firing. This diversity in DA autoreceptors could explain the various actions of DA in the brain.
authors.affiliation: Department of Physiology, Sungkyunkwan University School of Medicine, Samsung Biomedical Research Institute, Jangan-ku, Suwon, Korea.
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Jang
authors.forename: Miae
authors.initials: M
authors.lastname: Jang
authors.forename: Shin Hye
authors.initials: SH
authors.lastname: Kim
authors.forename: Ki Bum
authors.initials: KB
authors.lastname: Um
authors.forename: Yun Kyung
authors.initials: YK
authors.lastname: Kang
authors.forename: Hyun Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Sungkwon
authors.initials: S
authors.lastname: Chung
authors.forename: Myoung Kyu
authors.initials: MK
authors.lastname: Park
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism* / Q000494:pharmacology; D015259:Dopamine Agents / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D066298:In Vitro Techniques; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D018408:Patch-Clamp Techniques / Q000379:methods; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011954:Receptors, Dopamine / Q000235:genetics / Q000378:metabolism; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013223:Statistics as Topic; D013378:Substantia Nigra / Q000166:cytology*; D013779:Tetrodotoxin / Q000494:pharmacology; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics / Q000378:metabolism
chemical_list: D015259:Dopamine Agents; D012333:RNA, Messenger; D011954:Receptors, Dopamine; D026941:Sodium Channel Blockers; D013779:Tetrodotoxin; D014446:Tyrosine 3-Monooxygenase; D002118:Calcium; D004298:Dopamine