Jill MacLeod

Document Type

Honors Project

First Advisor

Dr. Brian Kelley

Degree Award Date

Spring 2001

Keywords

Adolescent Nicotine Exposure, Locomotor Effects, 7-0H DPAT, Adult C57 Mice

Disciplines

Chemicals and Drugs | Medicine and Health Sciences

Abstract

As past research seems to indicate, nicotine use during adolescence alters reward systems ( as noted with cocaine and alcohol). Motor responses to quipirole (D2 agonist), SKF 38393 (Dl agonist), and Haloperidol (02 antagonist) were affected by periadolescent nicotine exposure. Thus, early nicotine exposure may alter dopamine function, thereby influencing the effects of drugs acting on this system. Sensitivity to 7- OH-DPAT, a dopamine D3 agonist, was examined by testing motor activity of adult mice that were exposed to nicotine or saline (1.0 mg/kg, SC, M-F, b.i.d.) during postnatal days 25-60. Following a two-week drug-free period, the subjects were acclimated to the testing chamber (5 days, saline inj.), then motor activity was measured (every 5 min for 30 min, cm traveled) after IP injections of7-0H-DPAT (0.025, 0.0125, 0.006, and 0.003 mg/ml). Sessions with saline injections were conducted before and after each drug test. Significant differences between nicotine-treated and control subjects were observed at the 0.0125 and 0.006 mg/ml doses of7-0H-DPAT. Chronic dosing of0.003 mg/ml and 0.0075 mg/ml revealed that nicotine exposure resulted in less sensitization to motor disruptive effects of7-OH-DPAT. This change in sensitivity implies that dopamine 03 receptor systems are changed by adolescent nicotine use.

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