Changes in cholecystokinin mRNA expression in methamphetamine-induced behavioral sensitization.
Neuropeptide cholecystokinin (CCK) mRNA was measured in the rat brain subchronically treated with methamphetamine (MAP). Male Wistar rats were injected daily with MAP (3 or 6 mg/kg, i.p., once a day) or saline for 14 days. Progressive reinforcement was observed in MAP-induced stereotyped behaviors. After 7 or 14 days of discontinuation, the rats were decapitated and the brains were prepared for Northern blot analysis using 32P-labeled cDNA probes. Northern blot analysis revealed that the levels of CCK mRNA in the frontal cortex and the hippocampus of 3 or 6 mg/kg MAP-treated rats were significantly decreased, compared to the saline-treated controls. These findings indicate that the alteration in CCK mRNA levels in the frontal cortex and the hippocampus of MAP-treated rats persisted for at least 2 weeks and might be involved in the expression of MAP-induced long-lasting behavioral sensitization (reverse tolerance).
Fukamauchi
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Department of Molecular Medical Science, Tokyo Medical and Dental University, Japan.
D000818:Animals; D015152:Blotting, Northern; D001921:Brain / Q000378:metabolism*; D002766:Cholecystokinin / Q000096:biosynthesis*; D015342:DNA Probes; D005625:Frontal Lobe; D006624:Hippocampus / Q000378:metabolism; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology*; D015282:Octreotide / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017208:Rats, Wistar; D013239:Stereotyped Behavior / Q000187:drug effects*; D014158:Transcription, Genetic / Q000187:drug effects*
D015342:DNA Probes; D012333:RNA, Messenger; D008694:Methamphetamine; D002766:Cholecystokinin; D015282:Octreotide