DARPP-32 in the ciliary epithelium of the eye: a neurotransmitter-regulated phosphoprotein of brain localizes to secretory cells

J Histochem Cytochem. 1986 Nov;34(11):1465-8. doi: 10.1177/34.11.2877023.


DARPP-32, a phosphoprotein enriched in dopaminoceptive brain neurons containing the D-1 receptor subtype, probably functions as an intracellular third messenger to mediate some of the physiological effects of dopamine at the D-1 receptor. By immunohistochemistry in rat, cat, Rhesus monkey, and human, we have localized DARPP-32 to the non-pigmented epithelium of the ciliary body, the innermost layer of the bi-layered epithelium responsible for secretion of aqueous humor into the eye. The immunoreactive protein in rat ciliary body, identified by immunolabeling of a ciliary body extract separated by sodium dodecyl sulfate/polyacrylamide gel electrophoresis, is indistinguishable from DARPP-32 derived from rat caudatoputamen. By analogy with brain, we propose that DARPP-32 may act as a third messenger in the ciliary epithelium, probably through a dopaminergic mechanism.

Publication types

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

MeSH terms

  • Animals
  • Brain Chemistry*
  • Cats
  • Ciliary Body / analysis*
  • Dopamine and cAMP-Regulated Phosphoprotein 32
  • Epithelium / analysis
  • Fluorescent Antibody Technique
  • Histocytochemistry
  • Humans
  • Macaca mulatta
  • Nerve Tissue Proteins / analysis*
  • Nerve Tissue Proteins / immunology
  • Neurotransmitter Agents / physiology
  • Phosphoproteins / analysis*
  • Rats
  • Receptors, Dopamine / analysis


  • Dopamine and cAMP-Regulated Phosphoprotein 32
  • Nerve Tissue Proteins
  • Neurotransmitter Agents
  • Phosphoproteins
  • Receptors, Dopamine