A role for the anandamide membrane transporter in TRPV1-mediated neurosecretion from trigeminal sensory neurons

Neuropharmacology. 2005 Jul;49(1):25-39. doi: 10.1016/j.neuropharm.2005.01.031. Epub 2005 Apr 1.

Abstract

Many n-acylethanolamines utilize the anandamide membrane transporter (AMT) to gain facilitated access to the intracellular compartment, hence, we hypothesized that this mechanism might be important for anandamide (AEA)- and N-arachidonoyl-dopamine (NADA)-evoked CGRP release from cultured trigeminal ganglion (TG) neurons. Using [14C]AEA we demonstrated that TG neurons transported AEA in a FAAH- and AMT-inhibitable fashion. Although TRPV1-positive TG neurons were found to express fatty acid amide hydrolase, the application of FAAH inhibitors had no effect on AEA-evoked CGRP release. In contrast, application of the AMT inhibitors OMDM-2 or VDM-11 significantly reduced the potency and efficacy of AEA-, NADA- and capsaicin-evoked CGRP release. Moreover OMDM-2 (IC50 values ranging from 6.4-9.6 microM) and VDM-11 (IC50 values ranging from 5.3-11 microM) inhibited CGRP release evoked by EC80 concentrations of AEA, NADA and CAP and these values were consistent with IC50s obtained for inhibition of uptake. OMDM-2 had no effect on CGRP release per se while VDM-11 evoked CGRP release on its own (EC50 approximately 35 microM) in a CPZ-insensitive, but ruthenium red (RR)-sensitive fashion. This is the first demonstration that TG sensory neurons possess an AMT-like mechanism suggesting that this mechanism is important for the pharmacological action of AEA and NADA at native TRPV1 channels.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amidohydrolases / metabolism
  • Analysis of Variance
  • Animals
  • Arachidonic Acids / metabolism*
  • Arachidonic Acids / pharmacology
  • Benzyl Compounds / pharmacology
  • Calcitonin Gene-Related Peptide / metabolism
  • Carbon Isotopes / metabolism
  • Cells, Cultured
  • Cricetinae
  • Cricetulus
  • Dose-Response Relationship, Drug
  • Drug Interactions
  • Endocannabinoids
  • Enzyme Inhibitors / pharmacology
  • Immunohistochemistry / methods
  • Male
  • Membrane Proteins / metabolism*
  • Neurons / drug effects
  • Neurons / metabolism*
  • Polyunsaturated Alkamides
  • Radioimmunoassay / methods
  • Rats
  • Rats, Sprague-Dawley
  • TRPV Cation Channels / physiology*
  • Trigeminal Ganglion / cytology*

Substances

  • Arachidonic Acids
  • Benzyl Compounds
  • Carbon Isotopes
  • Endocannabinoids
  • Enzyme Inhibitors
  • Membrane Proteins
  • N-(2-methyl-3-hydroxyphenyl)-5,8,11,14-eicosatetraenamide
  • OMDM-2 cpd
  • Polyunsaturated Alkamides
  • TRPV Cation Channels
  • Trpv1 protein, rat
  • Amidohydrolases
  • fatty-acid amide hydrolase
  • Calcitonin Gene-Related Peptide
  • anandamide