Altered neurochemical levels in the rat brain following chronic nicotine treatment

• Published in: Journal of chemical neuroanatomy Vol. 59-60; pp. 29 - 35
• Main Authors: Falasca, Sara, Ranc, Vaclav, Petruzziello, Filomena, Khani, Abbas, Kretz, Robert, Zhang, Xiaozhe, Rainer, Gregor
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.09.2014
• Subjects: Acetylcholine - analysis; Acetylcholine - biosynthesis; Animals; Brain - drug effects; Brain - metabolism; Carnitine - analysis; Carnitine - biosynthesis; Chromatography, Liquid; Chronic nicotine; Dorsal striatum; Glutamic Acid - analysis; Glutamic Acid - biosynthesis; Hypothalamus; Mass Spectrometry; Neurochemicals; Nicotine - toxicity; Nicotinic Agonists - toxicity; Prefrontal cortex; Rats; Rats, Long-Evans; Chronic nicotine; Prefrontal cortex; Hypothalamus; Neurochemicals; Dorsal striatum
• ISSN: 0891-0618; 1873-6300
• DOI: 10.1016/j.jchemneu.2014.05.002

•Chronic nicotine treatment induced brain-specific changes of neurochemicals.•We observed a decrease of acetylcholine levels in the dorsal striatum.•The increase of glutamate levels was only found in prefrontal cortex.•The level of carnitine was robustly enhanced in the hypothalamus. Converging evidence shows that neurochemical systems are crucial mediators of nicotine dependence. Our present study evaluates the effect of 3-month chronic nicotine treatment on the levels of multiple quaternary ammonium compounds as well as glutamate and gamma aminobutyric acid in the rat prefrontal cortex, dorsal striatum and hypothalamus. We observed a marked decrease of acetylcholine levels in the dorsal striatum (22.88%, p<0.01), reflecting the impact of chronic nicotine in local interneuron circuits. We found decreases of carnitine in the dorsal striatum and prefrontal cortex (19.44%, p<0.01; 13.58%, p<0.01, respectively), but robust enhancements of carnitine in the hypothalamus (26.59%, p<0.01), which may reflect the alterations in food and water intake during chronic nicotine treatment. Finally, we identified an increase of prefrontal cortex glutamate levels (8.05%, p<0.05), supporting previous studies suggesting enhanced prefrontal activity during chronic drug use. Our study shows that quaternary ammonium compounds are regulated in a highly brain region specific manner during chronic nicotine treatment, and provides novel insights into neurochemical regulation during nicotine use.