Effects of amphetamine on locomotor activity in adult and juvenile alcohol-preferring and -nonpreferring rats

D. L. McKinzie, W. J. McBride, J. M. Murphy, L. Lumeng, T. K. Li

Research output: Contribution to journalArticle

19 Scopus citations


The objective of this study was to determine whether functional differences exist in amphetamine-induced locomotor activity between alcohol-naive alcohol-preferring (P) and -nonpreferring (NP) rats during postnatal development and during adulthood. Using a between-subjects design, 20- and 28-day-old P and NP rats (male and female counterbalanced, n = 11-16/line) were habituated for 30 min in a photocell activity field. Each rat received subcutaneous injections of saline or 0.3, 0.6 or 1.2 mg/kg d-amphetamine (AMPH) and were then tested for an additional 30 min. Because of age and line differences in basal locomotor activity, total activity counts during the 30-min postdrug period were standardized using Z-score transformations. In the 20- and 28-day-old rats, dose-dependent locomotor activity increases after AMPH injections were obtained at both ages, although activity levels were greater in the 20-day-old pups. The 20-day-old female NP rats showed greater AMPH-induced increases in locomotor activity than P rats, whereas at 28 days of age, male NP rats showed greater activity levels than P rats to AMPH. For the adult P and NP rats (n = 8/line/gender), a within-subject design was used. In the adults, the NP line had higher locomotor activity than the P line following AMPH injection, and male rats were activated more by AMPH than female rats. The results suggest that functioning of the DA system in the adult P line is reduced compared to the adult NP line, and this line difference is also observed to some degree at an early postweaning developmental period.

Original languageEnglish (US)
Pages (from-to)29-36
Number of pages8
JournalPharmacology Biochemistry and Behavior
Issue number1-2
StatePublished - Jan 2 2002


  • Alcohol-preferring rats
  • Amphetamine
  • Juvenile rats
  • Locomotor activity

ASJC Scopus subject areas

  • Biochemistry
  • Behavioral Neuroscience
  • Pharmacology

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