Lobeline attenuates methamphetamine-induced changes in vesicular monoamine transporter 2 immunoreactivity and monoamine depletions in the striatum

J Pharmacol Exp Ther. 2005 Jan;312(1):160-9. doi: 10.1124/jpet.104.072264. Epub 2004 Aug 26.

Abstract

L-Lobeline is an alkaloid that inhibits the behavioral effects of methamphetamine (METH) in rats. No studies have examined the effects of lobeline on the acute and long-term neurochemical changes produced by neurotoxic doses of METH. The effects of lobeline on METH-induced dopamine release, alterations in vesicular monoamine transporter 2 (VMAT-2) distribution, and long-term depletions of dopamine and serotonin (5-HT) content in the rat striatum were examined. METH increased body temperature and dopamine release, decreased VMAT-2 immunoreactivity at 1 and 24 h after METH, and decreased dopamine and 5-hydroxytryptamine (5-HT) content in striatum when examined 7 days later. Prevention of METH-induced hyperthermia attenuated the decrease in VMAT-2 as well as dopamine and 5-HT content. Lobeline pretreatment did not affect METH-induced dopamine release but attenuated the decreases in VMAT-2 after METH and the long-term decreases in striatal dopamine and 5-HT content. These effects of lobeline were due partly to the attenuation of METH-induced hyperthermia. The maintenance of hyperthermia during lobeline + METH exposure restored the effects of METH on decreases in VMAT-2 as well as dopamine and 5-HT content. To examine the effects of lobeline independent of its effects on METH-induced hyperthermia, lobeline was administered after METH when body temperature returned to normal. Lobeline treatment at 5 and 7 h after METH attenuated the METH-induced decreases in synaptosomal, membrane-associated, and vesicular VMAT-2 24 h after METH, as well as the METH-induced decreases in dopamine and 5-HT content 7 days later. Therefore, lobeline has both temperature-dependent and -independent neuroprotective effects against METH toxicity.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adrenergic Agents / pharmacology
  • Animals
  • Biogenic Monoamines / metabolism*
  • Corpus Striatum / drug effects*
  • Corpus Striatum / metabolism
  • Drug Interactions
  • Lobeline / pharmacology*
  • Male
  • Membrane Glycoproteins / metabolism*
  • Membrane Transport Proteins / metabolism*
  • Methamphetamine / pharmacology*
  • Rats
  • Rats, Sprague-Dawley
  • Vesicular Biogenic Amine Transport Proteins
  • Vesicular Monoamine Transport Proteins

Substances

  • Adrenergic Agents
  • Biogenic Monoamines
  • Membrane Glycoproteins
  • Membrane Transport Proteins
  • Vesicular Biogenic Amine Transport Proteins
  • Vesicular Monoamine Transport Proteins
  • Methamphetamine
  • Lobeline