Immunocytochemical localization of cannabinoid CB1 receptor and fatty acid amide hydrolase in rat retina

J Comp Neurol. 1999 Dec 6;415(1):80-90. doi: 10.1002/(sici)1096-9861(19991206)415:1<80::aid-cne6>;2-h.


Cannabinoids have major effects on central nervous system function. Recent studies indicate that cannabinoid effects on the visual system have a retinal component. Immunocytochemical methods were used to localize cannabinoid CB1 receptor immunoreactivity (CB1R-IR) and an endocannabinoid (anandamide and 2-arachidonylglycerol) degradative enzyme, fatty acid amide hydrolase (FAAH)-IR, in the rat retina. Double labeling with neuron-specific markers permitted identification of cells that were labeled with CB1R-IR and FAAH-IR. CB1R-IR was observed in all cells that were protein kinase C-immunoreactive (rod bipolar cells and a subtype of GABA-amacrine cell) as well as horizontal cells (identified by calbindin-IR). There was also punctate CB1R-IR in the distal one-third of the inner plexiform layer (IPL) that could not be assigned to a cell type. FAAH-IR was most prominent in large ganglion cells, whose dendrites projected to a narrow band in the proximal IPL. Weaker FAAH-IR was observed in the soma of horizontal cells (identified by calbindin-IR); the soma of large, but not small, dopamine amacrine cells (identified by tyrosine hydroxylase-IR); and dendrites of orthotopic- and displaced-starburst amacrine cells (identified by choline acetyltransferase-IR) but in less than 50% of the starburst amacrine cell somata. The extensive distribution of CB1R-IR on horizontal cells and rod bipolar cells indicates a role of endocannabinoids in scotopic vision, whereas the more widespread distribution of FAAH-IR indicates a complex control of endocannabinoid release and degradation in the retina.

Publication types

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

MeSH terms

  • Amidohydrolases / analysis*
  • Animals
  • Biomarkers
  • Cannabinoid Receptor Modulators
  • Cannabinoids / pharmacokinetics
  • Immunohistochemistry
  • Neurons / cytology
  • Neurons / metabolism*
  • Protein Kinase C / analysis
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Cannabinoid
  • Receptors, Drug / analysis*
  • Retina / cytology
  • Retina / metabolism*
  • Retinal Rod Photoreceptor Cells / cytology
  • Retinal Rod Photoreceptor Cells / metabolism
  • gamma-Aminobutyric Acid / analysis


  • Biomarkers
  • Cannabinoid Receptor Modulators
  • Cannabinoids
  • Receptors, Cannabinoid
  • Receptors, Drug
  • gamma-Aminobutyric Acid
  • Protein Kinase C
  • Amidohydrolases
  • fatty-acid amide hydrolase