Effects of n-hexanal on dopamine release in the striatum of living rats

Eur J Pharmacol. 2011 Jan 25;651(1-3):77-82. doi: 10.1016/j.ejphar.2010.11.004. Epub 2010 Nov 30.

Abstract

Green odor is present in many green leaves, vegetables, and fruits and is composed of four 6-carbon straight-chain alcohols, n-hexanol, (E)-2-hexenol, (Z)-3-hexenol, and (E)-3-hexenol, and four aldehydes, n-hexanal, (E)-2-hexenal, (Z)-3-hexenal, and (E)-3-hexenal. It has been reported that certain green odor compounds enhance dopamine release from rat brain striatal slices and rat pheochromocytoma cells (PC12 cells). It is well known that intracellular Ca(2+) levels regulate dopamine release. The amount of dopamine released by n-hexanal-treated PC12 cells decreased in cells pretreated with a membrane-permeable Ca(2+) chelator. In this study, the effect of n-hexanal on dopamine release in the brain striatum of living rats was studied using an in vivo brain microdialysis system. Local stimulation with n-hexanal diluted in Ringer's solution to 0.01%, 0.05%, or 0.1% enhanced dopamine release in a concentration-dependent manner. The amount of dopamine released with 0.01% n-hexanal administration significantly declined when either extracellular or intracellular Ca(2+) levels decreased. Furthermore, the extracellular dopamine concentration increased with perfusion of nomifensine, an inhibitor of dopamine uptake into cells. When nomifensine was co-perfused with n-hexanal into the striatum, extracellular dopamine release increased further. Accordingly, the concentration of dopamine metabolite and the ratio of dopamine metabolite to dopamine decreased after treatment with n-hexanal. These responses were similar to those seen with KCl stimulation. These data suggest that n-hexanal stimulates dopamine release but does not inhibit dopamine uptake in the brain striatum of living rats, and that dopamine release associated with n-hexanal is regulated by both extracellular and intracellular Ca(2+) levels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aldehydes / pharmacology*
  • Animals
  • Calcium / metabolism
  • Dopamine / metabolism*
  • Dopamine Uptake Inhibitors / pharmacology
  • Extracellular Space / drug effects
  • Extracellular Space / metabolism
  • In Vitro Techniques
  • Intracellular Space / drug effects
  • Intracellular Space / metabolism
  • Male
  • Microdialysis
  • Neostriatum / cytology
  • Neostriatum / drug effects*
  • Neostriatum / metabolism*
  • Potassium Chloride / pharmacology
  • Rats
  • Rats, Wistar

Substances

  • Aldehydes
  • Dopamine Uptake Inhibitors
  • Potassium Chloride
  • n-hexanal
  • Calcium
  • Dopamine