Changes in endocannabinoid and palmitoylethanolamide levels in eye tissues of patients with diabetic retinopathy and age-related macular degeneration

Prostaglandins Leukot Essent Fatty Acids. 2006 Dec;75(6):413-8. doi: 10.1016/j.plefa.2006.08.002. Epub 2006 Oct 2.


Cannabinoid receptors and the endocannabinoids (anandamide (N-arachidonoylethanolamine--AEA) and 2-arachidonoylglycerol (2-AG)), as well as the AEA congener, palmitoylethanolamide (PEA), are involved in ocular physiology. We measured endocannabinoid and PEA levels by isotope-dilution liquid chromatography-mass spectrometric analysis in post-mortem eye tissues of patients with diabetic retinopathy (DR) or age-related macular degeneration (AMD). In eyes with DR, significantly enhanced levels of AEA were found in the retina ( approximately 1.8-fold), ciliary body ( approximately 1.5-fold) and, to a lesser extent, cornea ( approximately 1.3-fold). Surprisingly, 2-AG levels were significantly higher ( approximately 3-fold) only in the iris, whereas PEA levels only slightly increased ( approximately 1.3-fold) in the ciliary body. In eyes with AMD, significantly enhanced levels of AEA were found in the choroid ( approximately 1.3-fold), ciliary body ( approximately 1.4-fold) and cornea ( approximately 1.4-fold), whereas in the retina only a trend towards an increase ( approximately 1.5-fold) was observed. The tissue- and disease-selective nature of the changes observed suggests that the compounds analyzed here may play different roles in the control of eye function under different pathological conditions.

MeSH terms

  • Amides
  • Arachidonic Acids / analysis*
  • Cannabinoid Receptor Modulators / analysis
  • Diabetic Retinopathy / metabolism*
  • Endocannabinoids
  • Ethanolamines
  • Eye / chemistry*
  • Glycerides / analysis*
  • Humans
  • Macular Degeneration / metabolism*
  • Palmitic Acids / analysis*
  • Polyunsaturated Alkamides / analysis*
  • Up-Regulation


  • Amides
  • Arachidonic Acids
  • Cannabinoid Receptor Modulators
  • Endocannabinoids
  • Ethanolamines
  • Glycerides
  • Palmitic Acids
  • Polyunsaturated Alkamides
  • palmidrol
  • glyceryl 2-arachidonate
  • anandamide