title: Nasal instillation of nanoparticle-rich diesel exhaust particles slightly affects emotional behavior and learning capability in rats.
abstract: In the present study, in order to reveal novel adverse effects of ultrafine particles (UFP) on the central nervous system, the effects of nanoparticle-rich diesel exhaust particles (NRDEP; count mode diameter, 21.45 nm) on emotional behavior, learning capability and brain neurotransmitter levels were studied in rats by intranasal instillation (iNI). NRDEP (10 and 50 µg/rat) was instilled into 2-week old infant, male rats once a week for 4 weeks. Spontaneous motor activity measured was observed to be inverse to the dose level. In active avoidance tests using a shuttle box, NRDEP-treated animals showed a lower avoidance performance than control animals given air-instillation. The levels of dopamine and its metabolite (DOPAC) in the medial mammillary nucleus of the brain tended to be lower in the NRDEP-treated animals. From these results, although the effects of NRDEP by iNI on the emotionality and the brain neurotransmitter levels were not fully clear, the results obtained by avoidance testing suggested involvement of UFP in learning capability.
authors.affiliation: First Laboratory of Toxicology, Hatano Research Institute, Food and Drug Safety Center, 729-5 Ochiai, Hadano, Kanagawa 257-8523, Japan. yokota.s@fdsc.or.jp
authors.forename: Syunji
authors.initials: S
authors.lastname: Yokota
authors.forename: Hiromasa
authors.initials: H
authors.lastname: Takashima
authors.forename: Ryo
authors.initials: R
authors.lastname: Ohta
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Saito
authors.forename: Takashi
authors.initials: T
authors.lastname: Miyahara
authors.forename: Yuka
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Tsukasa
authors.initials: T
authors.lastname: Negura
authors.forename: Mika
authors.initials: M
authors.lastname: Senuma
authors.forename: Kenji
authors.initials: K
authors.lastname: Usumi
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Hirabayashi
authors.forename: Takaho
authors.initials: T
authors.lastname: Watanabe
authors.forename: Shinji
authors.initials: S
authors.lastname: Horiuchi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Fujitani
authors.forename: Seishiro
authors.initials: S
authors.lastname: Hirano
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Fujimaki
mesh_terms: D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000281:Administration, Intranasal; D000393:Air Pollutants / Q000633:toxicity*; D000818:Animals; D000833:Animals, Suckling; D001362:Avoidance Learning / Q000187:drug effects*; D001522:Behavior, Animal / Q000187:drug effects*; D001921:Brain / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D004298:Dopamine / Q000378:metabolism; D009043:Motor Activity / Q000187:drug effects; D053758:Nanoparticles / Q000633:toxicity*; D051381:Rats; D001335:Vehicle Emissions / Q000633:toxicity*
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions; D015102:3,4-Dihydroxyphenylacetic Acid; D004298:Dopamine