Benzodiazepine selectively antagonize kainate-induced activation in the rat hippocampus.
Low intravenous doses of two benzodiazepines, lorazepam and diazepam, antagonized the activation of dorsal hippocampus CA1 pyramidal neurons by kainate to a greater extent than the activations produced by glutamate and acetylcholine. A similar effect was obtained with microiontophoretic application of two water-soluble benzodiazepines, flurazepam and chlordiazepoxide. Chlorpromazine and phenobarbital did not exert any consistent effect on kainate-induced activation. RO 15-1788, a benzodiazepine antagonist, prevented the effect of lorazepam on kainate-induced activation. The regional selectivity of this effect was indicated by the failure of lorazepam to produce a sustained reduction of kainate action in the CA3 hippocampal region and in the cerebral cortex. This selective antagonism by benzodiazepines of the excitation of selected limbic neurons via 'kainate-sensitive' receptors might be related to their anxiolytic effect.
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D014151:Anti-Anxiety Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D001570:Benzodiazepinones / Q000494:pharmacology; D002746:Chlorpromazine / Q000494:pharmacology; D003975:Diazepam / Q000494:pharmacology; D005442:Flumazenil; D005971:Glutamates / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects*; D007275:Injections, Intravenous; D007478:Iontophoresis; D007608:Kainic Acid / Q000037:antagonists & inhibitors*; D008140:Lorazepam / Q000494:pharmacology; D008297:Male; D010634:Phenobarbital / Q000494:pharmacology; D011712:Pyramidal Tracts / Q000187:drug effects; D011759:Pyrrolidines / Q000037:antagonists & inhibitors*; D051381:Rats; D011919:Rats, Inbred Strains
D014151:Anti-Anxiety Agents; D001570:Benzodiazepinones; D005971:Glutamates; D011759:Pyrrolidines; D005442:Flumazenil; D000109:Acetylcholine; D008140:Lorazepam; D003975:Diazepam; D007608:Kainic Acid; D002746:Chlorpromazine; D010634:Phenobarbital