Behavioral analysis of benzodiazepine-mediated inhibition in the early chick embryo.
Diazepam, a depressant benzodiazepine, produced a dose-dependent decrease in the spontaneous motility of 5-day embryos while Ro 5-3663, a convulsant benzodiazepine, had no apparent effect. Diazepam and 4 other benzodiazepines inhibited motility in 5-day embryos with a potency that paralleled their effectiveness in ligand-binding studies. Ro 11-5073/Ro 11-5231, depressant benzodiazepine enantiomers, stereospecifically inhibited motility in 4- and 5-day embryos. Ro 15-1788, a benzodiazepine antagonist, reversed the decrease in the motility of 4- and 5-day embryos caused by a depressant benzodiazepine, clonazepam. Ro 5-6945, a potent agonist for the non-neuronal (but not the neuronal) benzodiazepine receptor, had no apparent effect on motility in 5-day embryos. Benzodiazepine receptors appear at least as early as day 5 (and perhaps as early as day 4) in the chick embryo.
D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D001569:Benzodiazepines; D001921:Brain / Q000187:drug effects*; D002642:Chick Embryo; D004305:Dose-Response Relationship, Drug; D009043:Motor Activity / Q000187:drug effects*; D009433:Neural Inhibition / Q000187:drug effects*; D011956:Receptors, Cell Surface / Q000187:drug effects*; D011963:Receptors, GABA-A; D009435:Synaptic Transmission / Q000187:drug effects
D014151:Anti-Anxiety Agents; D011956:Receptors, Cell Surface; D011963:Receptors, GABA-A; D001569:Benzodiazepines