The adenylate cyclase receptor complex and aqueous humor formation

Yale J Biol Med. 1984 May-Jun;57(3):283-300.

Abstract

The secretory tissue of the eye, the ciliary processes, contains an enzyme receptor complex, composed of membrane proteins, the catalytic moiety of the enzyme adenylate cyclase, a guanyl nucleotide regulatory protein (or N protein), and other features. The enzyme can be activated by well-known neurohumoral or humoral agents, catecholamines, glycoprotein hormones produced by the hypothalamic pituitary axis, and other related compounds, including placental gonadotropin, organic fluorides, and forskolin, a diterpene. These compounds cause the ciliary epithelia to produce cyclic AMP at an accelerated rate. Cyclic AMP, as a second messenger, causes, either directly or indirectly, a decrease in the net rate of aqueous humor inflow that may be modulated by cofactors. Clinical syndromes fit the experimental data so that an integrated explanation can be given for the reduced intraocular pressure witnessed under certain central nervous system and adrenergic influences. The molecular biology of this concept provides important leads for future investigations that bear directly both upon the regulation of intraocular pressure and upon glaucoma.

Publication types

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

MeSH terms

  • Adenylyl Cyclases / physiology*
  • Animals
  • Aqueous Humor / drug effects
  • Aqueous Humor / physiology*
  • Cholera Toxin / pharmacology
  • Ciliary Body / drug effects
  • Ciliary Body / physiology
  • Colforsin
  • Cyclic AMP / physiology
  • Diterpenes / pharmacology
  • GTP-Binding Proteins / physiology*
  • Humans
  • In Vitro Techniques
  • Intraocular Pressure
  • Rabbits
  • Receptors, Adrenergic / physiology
  • Regional Blood Flow / drug effects

Substances

  • Diterpenes
  • Receptors, Adrenergic
  • Colforsin
  • Cholera Toxin
  • Cyclic AMP
  • GTP-Binding Proteins
  • Adenylyl Cyclases