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Effects of benzodiazepine and GABA antagonists on anticonflict effects of antianxiety drugs injected into the rat amygdala in a water-lick suppression test

Effects of benzodiazepine and GABA antagonists on anticonflict effects of antianxiety drugs... 213 98 98 1 1 Shigenobu Shibata Kimihiro Yamashita Etsuko Yamamoto Tohru Ozaki Showa Ueki Department of Pharmacology, Faculty of Pharmaceutical Sciences Kyushu University 62 812 Fukuoka Japan Department of Pharmacology 2, Medical School Nagasaki University Nagasaki Product Development Laboratory Fujisawa Pharmacology, Co., Ltd. Osaka Japan Abstract In order to elucidate the role of the amygdala in rat conflict behavior in a water lick suppression test, we examined the effect of lesions of various nuclei of the amygdaloid complex on this behavior. An anticonflict effect was produced by a lesion of the anterior part of central and basolateral amygdala, and lesion to the posterior part of the central amygdala, but not by posterior of the basolateral amygdala or medial amygdala lesions. These results suggest that the amygdala, especially the anterior part of the central and basolateral nuclei, plays an important role in conflict behavior of rats in the water lick test. In a second experiment, the effects of benzodiazepine- and GABA-antagonists on the anticonflict action of diazepam, zopiclone, and phenobarbital injected into the anterior part of central and basolateral amygdala were examined, also using a water lick suppression test. A dose-dependent anticonflict action was produced by systemic administration as well as by intra-amygdala injection of diazepam, zopiclone, lormetazepam, flurazepam and phenobarbital. The order of potency was lormetazepam>zopiclone≧diazepam>flurazepam ≧phenobarbital for both routes of injection. The antiamygdala effects of diazepam and zopiclone injected into the amygdala were completely reversed by Ro15-1788 and β-CCM but not by bicuculline, while the anticonflict effect of phenobarbital was reversed by β-CCM but not by Ro15-1788 or bicuculline. The present results strongly suggest that the anterior nuclei of central and basolateral amygdala are important sites of action of antianxiety drugs, and that an anticonflict action produced by intra-amygdala injection of benzodiazepines or barbiturate is mediated through the different receptor mechansims. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Psychopharmacology Springer Journals

Effects of benzodiazepine and GABA antagonists on anticonflict effects of antianxiety drugs injected into the rat amygdala in a water-lick suppression test

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References (21)

Publisher
Springer Journals
Copyright
Copyright © 1989 by Springer-Verlag
Subject
Biomedicine; Pharmacology/Toxicology; Psychiatry
ISSN
0033-3158
eISSN
1432-2072
DOI
10.1007/BF00442003
Publisher site
See Article on Publisher Site

Abstract

213 98 98 1 1 Shigenobu Shibata Kimihiro Yamashita Etsuko Yamamoto Tohru Ozaki Showa Ueki Department of Pharmacology, Faculty of Pharmaceutical Sciences Kyushu University 62 812 Fukuoka Japan Department of Pharmacology 2, Medical School Nagasaki University Nagasaki Product Development Laboratory Fujisawa Pharmacology, Co., Ltd. Osaka Japan Abstract In order to elucidate the role of the amygdala in rat conflict behavior in a water lick suppression test, we examined the effect of lesions of various nuclei of the amygdaloid complex on this behavior. An anticonflict effect was produced by a lesion of the anterior part of central and basolateral amygdala, and lesion to the posterior part of the central amygdala, but not by posterior of the basolateral amygdala or medial amygdala lesions. These results suggest that the amygdala, especially the anterior part of the central and basolateral nuclei, plays an important role in conflict behavior of rats in the water lick test. In a second experiment, the effects of benzodiazepine- and GABA-antagonists on the anticonflict action of diazepam, zopiclone, and phenobarbital injected into the anterior part of central and basolateral amygdala were examined, also using a water lick suppression test. A dose-dependent anticonflict action was produced by systemic administration as well as by intra-amygdala injection of diazepam, zopiclone, lormetazepam, flurazepam and phenobarbital. The order of potency was lormetazepam>zopiclone≧diazepam>flurazepam ≧phenobarbital for both routes of injection. The antiamygdala effects of diazepam and zopiclone injected into the amygdala were completely reversed by Ro15-1788 and β-CCM but not by bicuculline, while the anticonflict effect of phenobarbital was reversed by β-CCM but not by Ro15-1788 or bicuculline. The present results strongly suggest that the anterior nuclei of central and basolateral amygdala are important sites of action of antianxiety drugs, and that an anticonflict action produced by intra-amygdala injection of benzodiazepines or barbiturate is mediated through the different receptor mechansims.

Journal

Psychopharmacology – Springer Journals

Published: May 1, 1989

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