title: Identification of a developmentally-regulated and psychostimulant-inducible novel rat gene mrt3 in the neocortex.
abstract: The psychotomimetic effects of stimulant drugs including amphetamines and cocaine are known to change during the postnatal development in humans and experimental animals. To obtain an insight into the molecular basis of the onset of stimulant-induced psychosis, we have explored the gene transcripts that differentially respond to methamphetamine (MAP) in the developing rat brains using a differential cloning technique, the RNA arbitrarily-primed PCR. We identified from the rat neocortex a novel and developmentally regulated MAP-inducible gene mrt3 (MAP responsive transcript 3) that is transcribed to a presumable non-coding RNA of 3.8kb and is located on the reverse strand of the F-box/LRR-repeat protein 17-like gene mapped on the rat chromosome Xq12. The mrt3 mRNAs are predominantly expressed in the brain and lung. Acute MAP injection upregulated the mrt3 expression in the neocortex at postnatal day 50, but not days 8, 15 and 23, in a D1 receptor antagonist-sensitive manner. This upregulation was mimicked by another stimulant, cocaine, whereas pentobarbital and D1 antagonist failed to alter the mrt3 expression. Moreover, repeated treatment with MAP for 5 days inhibited the ability of the challenge dose of MAP or cocaine to increase the neocortical mrt3 expression without affecting the basal mrt3 mRNA levels on day 14 of withdrawal. These late-developing, cocaine-cross reactive, D1 antagonist-sensitive and long-term regulations of mrt3 by MAP are similar to those of stimulant-induced behavioral sensitization, a model of the onset and relapse of stimulant-induced psychosis and schizophrenia, and therefore may be associated with the pathophysiology of the model.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Yamamoto
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
authors.forename: Shin-ichiro
authors.initials: S
authors.lastname: Muraoka
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kajii
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
authors.forename: Asami
authors.initials: A
authors.lastname: Umino
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8519, Japan. Electronic address: tnis.psyc@tmd.ac.jp.
authors.forename: Toru
authors.initials: T
authors.lastname: Nishikawa
mesh_terms: D000818:Animals; D001483:Base Sequence; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003042:Cocaine / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D018757:GABA Modulators / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D005796:Genes; D008168:Lung / Q000254:growth & development / Q000378:metabolism; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology; D008969:Molecular Sequence Data; D019579:Neocortex / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism*; D010424:Pentobarbital / Q000494:pharmacology; D012333:RNA, Messenger; D022661:RNA, Untranslated / Q000235:genetics*; D017208:Rats, Wistar; D017447:Receptors, Dopamine D1 / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D000697:Central Nervous System Stimulants; D018492:Dopamine Antagonists; D018765:Dopamine Uptake Inhibitors; D018757:GABA Modulators; D012333:RNA, Messenger; D022661:RNA, Untranslated; D017447:Receptors, Dopamine D1; D008694:Methamphetamine; D010424:Pentobarbital; D003042:Cocaine
keywords: Behavioral sensitization; D1 receptor; Dopamine neurotransmission; Methamphetamine; Methamphetamine responsive transcript 3 (mrt3); Postnatal development