Abstract.
Objectives: The effects of 5-HT1A receptor agonists on the emotional behavior of naive or stressed mice were examined and compared with those of benzodiazepine anxiolytics. Methods: Changes in the emotional state of mice were evaluated in terms of changes in exploratory activity, i.e. total locomotor activity, numbers and duration of rearing and head-dipping and latency to the first head-dipping, using an automatic hole-board apparatus. Results: The 5-HT1A receptor full agonists flesinoxan (0.03–1 mg/kg, IP) and 8-OH-DPAT (0.03–1 mg/kg, IP), and the partial agonist buspirone (0.3–10 mg/kg, IP) dose-dependently decreased all of the exploratory behaviors. Significant decreases in both the number and duration of head-dips, and an increase in the latency to head-dipping were observed at 30 min after exposure to acute restraint stress (60 min). These emotional changes were scarcely improved by post-stress treatment with 5-HT1A receptor agonists, at doses that alone did not produce a significant behavioral effect. In contrast, pretreatment with flesinoxan (0.1–1 mg/kg, IP) or 8-OH-DPAT (0.1–1 mg/kg, IP) 24 h prior to exposure to stress dose-dependently suppressed the decrease in various exploratory behaviors that was observed immediately after the exposure to acute restraint stress. Moreover, pretreatment with buspirone (1–10 mg/kg, IP) 24 h prior to exposure to stress also significantly suppressed the decrease in rearing behavior and the increase in head-dip latency. However, changes in the emotional response to stress stimuli were not observed in mice that had been pretreated with the benzodiazepine anxiolytics diazepam (0.1–1 mg/kg, IP) and chlordiazepoxide (2–8 mg/kg, IP). Conclusions: The present study clearly demonstrates that the behavioral effects of 5-HT1A receptor agonists in both naive and stressed mice were quite different from those of benzodiazepine anxiolytics, as previously reported by us. Notably, 5-HT1A receptor agonists but not benzodiazepine anxiolytics protect against various emotional changes produced by stress stimuli, and the results suggest that activation of 5-HT1A receptors may facilitate some mechanism(s) involved in the recognition of and/or ability to cope with stressful situation.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
Author information
Authors and Affiliations
Additional information
Electronic Publication
Rights and permissions
About this article
Cite this article
Tsuji, M., Takeda, H. & Matsumiya, T. Different effects of 5-HT1A receptor agonists and benzodiazepine anxiolytics on the emotional state of naive and stressed mice: a study using the hole-board test. Psychopharmacology 152, 157–166 (2000). https://doi.org/10.1007/s002130000514
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/s002130000514