Forskolin lowers intraocular pressure by reducing aqueous inflow

Invest Ophthalmol Vis Sci. 1984 Mar;25(3):268-77.


Forskolin is a diterpene derivative of the plant Coleus forskohlii that stimulates adenylate cyclase activity without interacting with cell surface receptors. Forskolin lowers the intraocular pressure of rabbits, monkeys, and humans. In rabbits, net aqueous humor inflow decreases, outflow facility remains unchanged, and ciliary blood flow increases. Tolerance to the intraocular pressure lowering effect did not occur in rabbits after topical doses given every 6 hr for 15 days. In vitro forskolin activates adenylate cyclase of crude particulate homogenates prepared from cultured human ciliary epithelia or from dissected ciliary epithelial processes of rabbit or human eyes. This activation is not blocked by timolol. The stimulation of adenylate cyclase by isoproterenol in vitro is potentiated in the presence of forskolin. Forskolin represents a potentially useful class of antiglaucoma agents differing in molecular mechanism of action from previously used drugs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenylyl Cyclases / metabolism
  • Animals
  • Aqueous Humor / drug effects
  • Aqueous Humor / physiology*
  • Blood Pressure / drug effects
  • Ciliary Body / blood supply
  • Ciliary Body / enzymology
  • Colforsin
  • Diterpenes / administration & dosage
  • Diterpenes / pharmacology*
  • Dose-Response Relationship, Drug
  • Drug Synergism
  • Drug Tolerance
  • Female
  • Humans
  • In Vitro Techniques
  • Intraocular Pressure / drug effects*
  • Iris / blood supply
  • Isoproterenol / pharmacology
  • Macaca
  • Male
  • Rabbits
  • Regional Blood Flow / drug effects
  • Timolol / pharmacology


  • Diterpenes
  • Colforsin
  • Timolol
  • Adenylyl Cyclases
  • Isoproterenol