beta-Carbolines enhance shock-induced suppression of drinking in rats.

Abstract

By using Vogel''s method to test the anxiolytic action of benzodiazepines and reducing the intensity of the current delivered to the drinking tube, it is possible to distinguish the pharmacological activity of 3 types of ligands for the benzodiazepine recognition site. An anticonflict action typical of anxiolytic benzodiazepines, a proconflict action typical of many .beta.-carbolines, including FG-7142 (.beta.-carboline-3-carboxylic acid ethyl ester methyl amide), and an antagonistic action of the proconflict and anticonflict actions typical of RO-15-1788 (ethyl-8-fluoro-5,6-dihydro-5-methyl-6-oxo-4H-imidazol-[1,5-a]-[1,4]-benzodiazepine-3-carboxylate) and CGS-8216 (2-phenylpyrazolo-[4,3-c]-quinolin-3-(5H)-one). Pentylenetetrazole, which causes convulsions by interacting with a subunit of the GABA receptor that is different from the benzodiazepine recognition site, also induces a proconflict action that is antagonized by anxiolytic benzodiazepines but not by RO-15-1788.