TY - JOUR T1 - Nicotine Infusion Modulates Immobilization Stress-Triggered Induction of Gene Expression of Rat Catecholamine Biosynthetic Enzymes JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 884 LP - 892 VL - 291 IS - 2 AU - Lidia Serova AU - Emil Danailov AU - Firas Chamas AU - Esther L. Sabban Y1 - 1999/11/01 UR - http://jpet.aspetjournals.org/content/291/2/884.abstract N2 - The relationship between nicotine and stress is complex and paradoxical. Although people claim they smoke because it relaxes them, nicotine can trigger some of the effects observed with stress, including the release and synthesis of the catecholamines and their biosynthetic enzymes. This study examined one aspect of this confusing relationship between nicotine and stress. Multiple injections of nicotine bitartrate (5 mg/kg) elevated mRNA levels for the catecholamine biosynthetic enzymes, tyrosine hydroxylase (TH), dopamine β-hydroxylase (DBH), and phenylethanolamineN-methyltransferase, and of preproneuropeptide Y in rat adrenal medulla more than did 1 mg/kg of nicotine bitartrate. In the locus ceruleus, substantia nigra, and ventral tegmental area both doses equally induced TH mRNA levels. Nicotine infusion (15 mg/kg/day) did not affect adrenal mRNA levels for any of the genes of interest and did not increase plasma corticosterone levels. However, in rats pre-exposed to nicotinic infusions, the response to a single immobilization (IMO) stress was markedly attenuated with respect to changes in adrenomedullary TH, DBH, and phenylethanolamineN-methyltransferase mRNA levels and in c-Fos protein levels. In the central nervous system, the chronic infusion of nicotine prevented the induction of TH mRNA by repeated IMO stress in the ventral tegmental area (but not in substantia nigra) and of DBH mRNA by single IMO in the locus ceruleus. These findings may explain some of the complex interactions between stress and exposure to nicotine. The American Society for Pharmacology and Experimental Therapeutics ER -