Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Actions and some interactions of 5-HT 1A ligands in the elevated X-maze and effects of dorsal raphe lesions

Actions and some interactions of 5-HT 1A ligands in the elevated X-maze and effects of dorsal... 213 106 106 4 4 M. A. E. Critchley K. Njung'e Sheila L. Handley Pharmacology Department Wellcome Research Laboratories Beckenham Kent UK Kenya Medical Research Institute P.O. Box 54840 Nairobi, Kenya South Africa Pharmacology Research, Pharmaceutical Sciences Institute Aston University B4 7ET Birmingham UK Abstract Effects of 5-HT 1A agonists and partial agonists on open/total arm entry ratio (OTR) have been examined in the elevated X-maze anxiety model. 8-OH-DPAT (0.05–0.2 mg/kg), RU 24969 (0.5–2.0 mg/kg) and BAY R 1521 (0.1–1.2 mg/kg) produced dose-dependent reductions in OTR, signifying anxiogenic effects. Buspirone reduced OTR only at doses (0.25–5.0 mg/kg) decreasing total entries; gepirone (0.1–5.0 mg/kg) was inactive. Ipsapirone (0.25–5.0 mg/kg) increased OTR and at 1.0 mg/kg antagonised the anxiogenic action of 8-OH-D-PAT, RU 24969 and BAY R 1531. Gepirone (2.5 mg/kg) failed to antagonise 8-OH-DPAT, but the dose was limited by its effect on total entries. The anxiogenic effect of a low dose of 8-OH-DPAT was also prevented by p -chlorophenylalanine ( p -CPA) pretreatment and reversed to anxiolytic by 5,7-dihydroxytryptamine lesions of dorsal raphe, which spared median raphe. These lesions also abolished the anxiolytic effect of ipsapirone without affecting the anxiogenic response to yohimbine. This study provides preliminary evidence that 8-OH-DPAT may be capable of acting as an agonist and ipsapirone as an antagonist at a presynaptic site related to dorsal raphe which is separate from the site of action of yohimbine. 5-HT 1A agonists and partial agonists may have multiple sites and/or mechanisms of action in the elevated X-maze. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Psychopharmacology Springer Journals

Actions and some interactions of 5-HT 1A ligands in the elevated X-maze and effects of dorsal raphe lesions

Psychopharmacology , Volume 106 (4) – Apr 1, 1992

Loading next page...
 
/lp/springer-journals/actions-and-some-interactions-of-5-ht-1a-ligands-in-the-elevated-x-7LE06JllVE

References (53)

Publisher
Springer Journals
Copyright
Copyright © 1992 by Springer-Verlag
Subject
Biomedicine; Pharmacology/Toxicology; Psychiatry
ISSN
0033-3158
eISSN
1432-2072
DOI
10.1007/BF02244819
Publisher site
See Article on Publisher Site

Abstract

213 106 106 4 4 M. A. E. Critchley K. Njung'e Sheila L. Handley Pharmacology Department Wellcome Research Laboratories Beckenham Kent UK Kenya Medical Research Institute P.O. Box 54840 Nairobi, Kenya South Africa Pharmacology Research, Pharmaceutical Sciences Institute Aston University B4 7ET Birmingham UK Abstract Effects of 5-HT 1A agonists and partial agonists on open/total arm entry ratio (OTR) have been examined in the elevated X-maze anxiety model. 8-OH-DPAT (0.05–0.2 mg/kg), RU 24969 (0.5–2.0 mg/kg) and BAY R 1521 (0.1–1.2 mg/kg) produced dose-dependent reductions in OTR, signifying anxiogenic effects. Buspirone reduced OTR only at doses (0.25–5.0 mg/kg) decreasing total entries; gepirone (0.1–5.0 mg/kg) was inactive. Ipsapirone (0.25–5.0 mg/kg) increased OTR and at 1.0 mg/kg antagonised the anxiogenic action of 8-OH-D-PAT, RU 24969 and BAY R 1531. Gepirone (2.5 mg/kg) failed to antagonise 8-OH-DPAT, but the dose was limited by its effect on total entries. The anxiogenic effect of a low dose of 8-OH-DPAT was also prevented by p -chlorophenylalanine ( p -CPA) pretreatment and reversed to anxiolytic by 5,7-dihydroxytryptamine lesions of dorsal raphe, which spared median raphe. These lesions also abolished the anxiolytic effect of ipsapirone without affecting the anxiogenic response to yohimbine. This study provides preliminary evidence that 8-OH-DPAT may be capable of acting as an agonist and ipsapirone as an antagonist at a presynaptic site related to dorsal raphe which is separate from the site of action of yohimbine. 5-HT 1A agonists and partial agonists may have multiple sites and/or mechanisms of action in the elevated X-maze.

Journal

PsychopharmacologySpringer Journals

Published: Apr 1, 1992

There are no references for this article.