Nicotine induced behavioral locomotor sensitization

• Published in: Progress in neuro-psychopharmacology & biological psychiatry 2001, Vol.25 (1), p.59-71
• Main Author: Domino, Edward F.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Caffeine - pharmacology; Central nervous system; Central neurotransmission. Neuromudulation. Pathways and receptors; dexamethasone; Dexamethasone - pharmacology; Dizocilpine Maleate - pharmacology; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Tolerance; Female; Fundamental and applied biological sciences. Psychology; Medical sciences; motor activity; Motor Activity - drug effects; nicotine; Nicotine - pharmacology; Rats; Rats, Sprague-Dawley; stimulation; Tobacco, tobacco smoking; Toxicology; Vertebrates: nervous system and sense organs
• ISSN: 0278-5846; 1878-4216
• DOI: 10.1016/S0278-5846(00)00148-2

1. Nicotine behavioral sensitization of locomotor activity was investigated in adult female Sprague Dawley rats. Five different experiments were performed with nicotine in various doses of 0.1, 0.32, or 1.0 mg/kg i.p. These included: 1) effects of daily nicotine for 6 days, 2) effects of once per week nicotine for 3 weeks, 3) effects of MK-801 on nicotine-induced locomotor activity, 4) effects of dexamethasone on nicotine-induced locomotor activity, 5) induction of tolerance to nicotine-induced locomotor sensitization and lack of cross tolerance to caffeine. 2. Locomotor activity was measured with a photoelectric computerized system. The first dose of nicotine (0.32 mg/kg) induced marked locomotor depression. Once daily injection of 0.32 mg/kg of nicotine for 6 days produced tolerance to its depressant effects and sensitized the rats to its stimulant effects. Three once weekly doses of 0.32 mg/kg of nicotine also produced tolerance to its depressant effects and some locomotor stimulation. 3. Daily pretreatment for 5 days with a dose of 0.18 mg/kg of MK-801 i.p. partially antagonized the locomotor depressant and stimulant actions of nicotine. 4. Dexamethasone (1 mg/kg i.p.) daily pretreatment barely reduced nicotine locomotor depression and only very slightly enhanced locomotor stimulation. 5. Accumulating doses of 0.32 and 1.0 mg/kg b.i.d. of nicotine produced tolerance to its locomotor stimulant effects in rats previously sensitized to 0.32 mg/kg. There was no cross-tolerance to 32 mg/kg of caffeine citrate in previously sensitized animals tolerant to the stimulant effects of nicotine.