Long-lasting alterations in 5-HT2A receptor after a binge regimen of methamphetamine in mice

Int J Neuropsychopharmacol. 2014 Oct;17(10):1647-58. doi: 10.1017/S1461145714000455. Epub 2014 Apr 24.

Abstract

The repeated administration of methamphetamine (MA) to animals in a single-day 'binge' dosing regimen produces damage to dopamine and serotonin terminals and psychosis-like behaviours similar to those observed in MA abusers. The present study aimed to examine the effects of MA binge exposure on 5-HT2A receptors, the subtype of serotonin receptors putatively involved in psychosis. ICR male mice were treated with MA (4 × 5 mg/kg) or saline at 2 h intervals. Recognition memory and social behaviours were sequentially evaluated by a novel location recognition test, a novel object recognition test, a social interaction and a nest-building test to confirm the persistent cognitive and behavioural impairments after this dosing regimen. Subsequently, a hallucinogenic 5-HT2A/2C receptor agonist 2,5-dimethoxy-4-iodoamphetamine (DOI)-induced head-twitch, molecular and electrophysiological responses were monitored. Finally, the levels of 5-HT2C, 5-HT1A, 5-HT2A and mGlu2 receptors in the medial prefrontal cortex were determined. MA binge exposure produced recognition memory impairment, reduced social behaviours, and increased DOI-induced head-twitch response, c-Fos and Egr-2 expression and field potentials in the medial prefrontal cortex. Furthermore, MA binge exposure increased 5-HT2A and decreased mGlu2 receptor expression in the medial frontal cortex, whereas 5-HT2C and 5-HT1A receptors were unaffected. These data reveal that the increased behavioural, molecular and electrophysiological responses to DOI might be associated with an up-regulation of 5-HT2A receptors in the medial prefrontal cortex after MA binge exposure. Identifying the biochemical alterations that parallel the behavioural changes in a mouse model of MA binge exposure may facilitate targeting therapies for treatment of MA-related psychiatric disorders.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amphetamines / pharmacology
  • Animals
  • Central Nervous System Stimulants / administration & dosage*
  • Early Growth Response Protein 2 / metabolism
  • Evoked Potentials / drug effects
  • Evoked Potentials / physiology
  • Exploratory Behavior / drug effects
  • Gene Expression Regulation / drug effects*
  • Head Movements / drug effects
  • In Vitro Techniques
  • Interpersonal Relations
  • Male
  • Methamphetamine / administration & dosage*
  • Mice
  • Mice, Inbred ICR
  • Prefrontal Cortex / drug effects
  • Prefrontal Cortex / metabolism
  • Proto-Oncogene Proteins c-fos / metabolism
  • Receptor, Serotonin, 5-HT2A / metabolism*
  • Recognition, Psychology / drug effects
  • Serotonin Receptor Agonists / pharmacology

Substances

  • Amphetamines
  • Central Nervous System Stimulants
  • Early Growth Response Protein 2
  • Egr2 protein, mouse
  • Proto-Oncogene Proteins c-fos
  • Receptor, Serotonin, 5-HT2A
  • Serotonin Receptor Agonists
  • Methamphetamine
  • 4-iodo-2,5-dimethoxyphenylisopropylamine