title: Expression of D1 but not D2 dopamine receptors in striatal neurons producing neurokinin B in rats.
abstract: Neostriatal projection neurons are known to be largely divided into two groups, striatoentopeduncular/striatonigral and striatopallidal neurons, which mainly express D1 and D2 dopamine receptors, respectively. Recently, a small population of neostriatal neurons have been reported to produce neurokinin B (NKB), and send their axons mainly to the basal forebrain regions. To reveal which type of dopamine receptors were expressed by these NKB-producing neurons, we examined rat striatal neurons by combining immunofluorescence labeling for preprotachykinin B (PPTB), the precursor of NKB, and fluorescence in situ hybridization labeling for dopamine receptors. Fluorescent signals for D1 receptor mRNA were detected in 85-89% of PPTB-immunopositive neurons in the neostriatum, accumbens nucleus and lateral stripe of the striatum, whereas almost no signal for D2 receptor was observed in PPTB-positive striatal neurons. To further reveal intracellular signaling downstream of D1 receptor in PPTB-producing neurons, we used a double immunofluorescence labeling method to study the localization of some substrates for protein kinase A (PKA), which was known to be activated by D1 receptor. Although only 3-7% of PPTB-immunopositive striatal neurons displayed immunoreactivity for dopamine- and cAMP-regulated phosphoprotein of 32 kDa, a well-known PKA substrate expressed in the two major groups of neostriatal projection neurons, 60-64% of PPTB-positive striatal neurons exhibited immunoreactivity for striatal-enriched tyrosine phosphatase. These results suggest that NKB-producing neostriatal neurons are similar to striatoentopeduncular/striatonigral neurons in the usage of dopamine receptor subtypes, but different from the two major groups of neostriatal projection neurons in terms of the downstream signaling of dopamine receptors.
authors.affiliation: Department of Anatomy for Oral Sciences, Graduate School of Medical and Dental Sciences, Advanced Therapeutic Course, Field of Neurology, Kagoshima University, Kagoshima 890-8544, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Sonomura
authors.forename: Kouichi
authors.initials: K
authors.lastname: Nakamura
authors.forename: Takahiro
authors.initials: T
authors.lastname: Furuta
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Hioki
authors.forename: Akinori
authors.initials: A
authors.lastname: Nishi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Yamanaka
authors.forename: Masanori
authors.initials: M
authors.lastname: Uemura
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kaneko
mesh_terms: D000818:Animals; D003342:Corpus Striatum / Q000166:cytology*; D051937:Dopamine and cAMP-Regulated Phosphoprotein 32 / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology*; D017404:In Situ Hybridization, Fluorescence / Q000379:methods; D008297:Male; D008954:Models, Biological; D015287:Neurokinin B / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D020320:Oligoribonucleotides, Antisense / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017447:Receptors, Dopamine D1 / Q000235:genetics / Q000378:metabolism*; D017448:Receptors, Dopamine D2 / Q000235:genetics / Q000378:metabolism*
chemical_list: D051937:Dopamine and cAMP-Regulated Phosphoprotein 32; D020320:Oligoribonucleotides, Antisense; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D015287:Neurokinin B