Activation of membrane receptors by a neurotransmitter conjugate designed for surface attachment

Biomaterials. 2005 May;26(14):1895-903. doi: 10.1016/j.biomaterials.2004.06.007.


The derivatization of surfaces with bioactive molecules is a research area of growing importance for cell and tissue engineering. Tetherable molecules used in such applications must contain an anchoring moiety as well as the biofunctional group, typically along with a spacer to prevent steric clashes between the target molecule and the tethering surface. Post-synaptic membrane receptors at chemical synapses in neural tissue mediate signaling to the post-synaptic neuron and are activated by the binding of diffusible neurotransmitter molecules released by the pre-synaptic neuron. However, little attention has been directed at developing neurotransmitter analogs that might retain functionality when tethered to a surface that could be interfaced with post-synaptic receptor proteins. Muscimol (5-aminomethyl-3-hydroxyisoxazole), an analog of GABA (gamma-aminobutryic acid), is a known potent agonist of GABA(A) and GABA(C) post-synaptic receptors found in retina and other central nervous system tissue. The present paper reports experiments testing the electrophysiological activity of "muscimol-biotin" on cloned GABA receptors expressed in Xenopus oocytes. This compound, which is potentially suitable for tethering at avidin-coated surfaces, consists of muscimol conjugated through an N-acyl linkage to a 6-aminohexanoyl chain that is distally terminated by biotin. We find that muscimol-biotin, as well as a structurally similar compound (muscimol-BODIPY) containing a bulky fluorophore at the distal end of the aminohexanoyl chain, exhibits substantial agonist activity at GABA(A) and GABA(C) receptors. Muscimol-biotin and other similarly biotinylated neurotransmitter analogs, in combination with surface functionalization using avidin-biotin technology, may be useful in applications involving the controlled activation of neuronal post-synaptic receptors by surface-attached molecules.

Publication types

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

MeSH terms

  • Animals
  • Cells, Cultured
  • Coated Materials, Biocompatible / pharmacology
  • GABA-A Receptor Agonists
  • GABA-B Receptor Agonists
  • Membrane Potentials / drug effects
  • Membrane Potentials / physiology*
  • Muscimol / pharmacology*
  • Neurotransmitter Agents / pharmacology*
  • Oocytes / drug effects
  • Oocytes / physiology*
  • Receptors, Cell Surface / agonists
  • Receptors, Cell Surface / metabolism
  • Receptors, GABA-A / metabolism*
  • Receptors, GABA-B / metabolism*
  • Recombinant Proteins / metabolism
  • Xenopus laevis


  • Coated Materials, Biocompatible
  • GABA-A Receptor Agonists
  • GABA-B Receptor Agonists
  • Neurotransmitter Agents
  • Receptors, Cell Surface
  • Receptors, GABA-A
  • Receptors, GABA-B
  • Recombinant Proteins
  • Muscimol