Lobelane decreases methamphetamine self-administration in rats

Eur J Pharmacol. 2007 Sep 24;571(1):33-8. doi: 10.1016/j.ejphar.2007.06.003. Epub 2007 Jun 13.

Abstract

Lobelane, a minor alkaloid of Lobelia inflata and a synthetic, des-oxy analog of lobeline, has good affinity for the vesicular monoamine transporter and the dopamine transporter. The current study examined the ability of lobelane to specifically decrease methamphetamine self-administration. Rats were trained on a fixed ratio 5 schedule of reinforcement to self-administer methamphetamine (0.05 mg/kg/infusion, i.v.) or to respond for sucrose pellets. Upon reaching stable responding, rats were pretreated with lobelane (0.1, 1, 3, 5.6, or 10 mg/kg, s.c.) or saline, 15 min prior to the operant session. To assess the effect of repeated lobelane on methamphetamine self-administration, rats were pretreated with lobelane (5.6 or 10 mg/kg, s.c.) for 7 sessions. Behavioral specificity was further investigated by assessing the effects of lobelane (0.1, 1, 3, 5, or 10 mg/kg, s.c.) or saline on locomotor activity. Within the dose range tested, lobelane dose-dependently decreased methamphetamine self-administration, while having no effect on sucrose-maintained responding. Locomotor activity was decreased following only the highest dose of lobelane (10 mg/kg). Across repeated pretreatments, tolerance developed to the effect of lobelane on methamphetamine self-administration, demonstrating that the ability of lobelane to specifically decrease methamphetamine self-administration is a transient effect. Thus, taken together, the results show that although lobelane interacts with the pharmacological targets believed to be responsible for its ability to decrease methamphetamine self-administration, removal of the oxygen functionalities from the lobeline molecule may have afforded a compound with an altered pharmacokinetic and/or pharmacodynamic profile.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Amphetamine-Related Disorders / physiopathology
  • Amphetamine-Related Disorders / prevention & control
  • Amphetamine-Related Disorders / psychology
  • Animals
  • Central Nervous System Stimulants / administration & dosage
  • Dose-Response Relationship, Drug
  • Infusions, Intravenous
  • Lobeline / analogs & derivatives*
  • Lobeline / pharmacology*
  • Male
  • Methamphetamine / administration & dosage*
  • Molecular Structure
  • Motor Activity / drug effects*
  • Rats
  • Rats, Sprague-Dawley
  • Self Administration
  • Sucrose / administration & dosage

Substances

  • Central Nervous System Stimulants
  • Methamphetamine
  • Sucrose
  • Lobeline