Repeated exposure to cocaine differently modulates BDNF mRNA and protein levels in rat striatum and prefrontal cortex.
In this report we investigated the modulation of the neurotrophin brain-derived neurotrophic factor (BDNF) following single or repeated injections with cocaine. Dose-response experiments revealed that a single dose of cocaine (5 mg/kg) is sufficient to upregulate BDNF mRNA levels selectively in rat prefrontal cortex 2 h after the injection, an effect that persists at least for 24 h and is paralleled by enhanced expression of mature (m)BDNF protein. Five consecutive injections of the psychostimulant (5 mg/kg) potentiate the increase of BDNF mRNA levels 2 h after the last treatment, presumably as a result of the enhancement of cAMP response element-binding protein (CREB) phosphorylation, an effect that vanishes 72 h later. Conversely, precursor (pro-) and mBDNF protein forms were markedly reduced 2 h and 72 h post-injection in the prefrontal cortex. Interestingly, in the striatum we found that repeated cocaine injection increased pro-BDNF levels without altering the mature form of the neurotrophin. Our results suggest that cocaine differently affects BDNF transcription and translation in a region-selective manner, but might also alter neurotrophin processing. These data further support the notion that the corticostriatal network is highly vulnerable to the effects of cocaine, and suggest that abnormal regulation of BDNF expression could contribute, at least in part, to the functional defects observed in drug abusers.
Fumagalli
Fabio
F
Center of Neuropharmacology, Department of Pharmacological Sciences, University of Milan, Via Balzaretti 9, 20133 Milan, Italy.
Di Pasquale
Laura
L
Caffino
Lucia
L
Racagni
Giorgio
G
Riva
Marco Andrea
MA
D000779:Anesthetics, Local / Q000008:administration & dosage*; D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000235:genetics / Q000378:metabolism*; D050882:CREB-Binding Protein / Q000378:metabolism; D003042:Cocaine / Q000008:administration & dosage*; D003342:Corpus Striatum / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D005786:Gene Expression Regulation / Q000187:drug effects; D008297:Male; D017397:Prefrontal Cortex / Q000187:drug effects*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D000779:Anesthetics, Local; D019208:Brain-Derived Neurotrophic Factor; D012333:RNA, Messenger; D050882:CREB-Binding Protein; D003042:Cocaine