Differential neurochemical consequences of an escalating dose-binge regimen followed by single-day multiple-dose methamphetamine challenges

J Neurochem. 2008 Jun;105(5):1873-85. doi: 10.1111/j.1471-4159.2008.05269.x. Epub 2008 Feb 1.

Abstract

Chronic intake of methamphetamine (METH) causes tolerance to its behavioral and subjective effects. To better mimic human patterns of drug abuse, the present study used a rodent model that took into account various facets of human drug administration and measured METH-induced effects on brain monoamine levels. Adult male Sprague-Dawley rats were injected with METH or saline according to an escalating dose schedule for 2 weeks. This was followed by a challenge regimen of either saline or one of two doses of METH (3 x 10 mg/kg every 2 h or 6 x 5 mg/kg given every hour, both given within a single day). Both challenge doses of METH caused significant degrees of depletion of dopamine in the striatum and norepinephrine and serotonin in the striatum, cortex, and hippocampus. Animals pre-treated with METH showed significant attenuation of METH-induced striatal dopamine depletion but not consistent attenuation of norepinephrine and serotonin depletion. Unexpectedly, METH pre-treated animals that received the 3 x 10 mg/kg challenge showed less increases in tympanic temperatures than saline pre-treated rats whereas METH pre-treated animals that received the 6 x 5 mg/kg METH challenge showed comparable increases in temperatures to saline pre-treated rats. Therefore, pre-treatment-induced partial protection against monoamine depletion is probably not because of attenuated METH-induced hyperthermia in those rats.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Intramural

MeSH terms

  • Amphetamine-Related Disorders / metabolism
  • Animals
  • Brain Chemistry / drug effects*
  • Brain Chemistry / physiology*
  • Dopamine / metabolism
  • Dose-Response Relationship, Drug
  • Drug Administration Schedule
  • Male
  • Methamphetamine / administration & dosage*
  • Methamphetamine / toxicity*
  • Rats
  • Rats, Sprague-Dawley

Substances

  • Methamphetamine
  • Dopamine