Colocalization of TrkB and brain-derived neurotrophic factor proteins in green-red-sensitive cone outer segments

Invest Ophthalmol Vis Sci. 2000 Nov;41(12):4014-21.


Purpose: To examine the distribution of neurotrophins (NTs) and their catalytic receptors in adult rat photoreceptors.

Methods: Immunocytochemistry and Western blot analyses were performed using primary antibodies raised against NTs (nerve growth factor [NGF], brain-derived neurotrophic factor [BDNF], NT-3, and NT-4/5) and NT receptors (TrkA, TrkB, TrkC, and p75NTR). Double-labeling of retinal sections with opsin-specific antibodies was performed to identify each photoreceptor type. Competitive experiments using excess recombinant NT or Trk receptors confirmed the binding specificity of each antibody.

Results: TrkB and BDNF immunoreactivity was colocalized in cone outer segments. TrkB and BDNF were detected in all green-red-sensitive cones, but not in blue-UV cones or rods, and other NTs and NT receptors were not detected in any of the photoreceptor types.

Conclusions: The findings suggest a specific role for BDNF through its signaling receptor TrkB in the function and maintenance of green-red cones, the predominant cone type in the rat retina.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western
  • Brain-Derived Neurotrophic Factor / metabolism*
  • Color Perception
  • Immunoenzyme Techniques
  • Rats
  • Rats, Sprague-Dawley
  • Receptor, trkB / metabolism*
  • Retinal Cone Photoreceptor Cells / metabolism*
  • Rod Opsins / metabolism


  • Brain-Derived Neurotrophic Factor
  • Rod Opsins
  • Receptor, trkB