The receptor antagonist actions are described for a novel bicyclic dinitrile compound (BIDN, 3,3-bis-(trifluoromethyl)-bicyclo [2.2.1] heptane-2,2-dicarbonitrile) on a Drosophila melanogaster homo-oligomeric GABA receptor expressed in Xenopus oocytes. BIDN blocked the wild-type form of the receptor in a neither purely competitive, nor purely non-competitive manner, being dependent on the GABA concentration yet insurmountable, and block was independent of the membrane potential. BIDN was found to be less effective against a mutant (A302 → S) form of the receptor resistant to dieldrin and picrotoxinin. This cross resistance of dieldrin-resistant receptors to BIDN is of interest in the light of recent findings that BIDN binding to insect membranes is displaced competitively by dieldrin, but not by picrotoxinin.
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Clinical Neurology
- Developmental Biology