Changes in head-dipping behavior in the hole-board test reflect the anxiogenic and/or anxiolytic state in mice.
The effects of treatment with anxiogenic or anxiolytic agents and exposure to acute restraint stress on emotional behavior in mice were examined using an automatic hole-board apparatus. 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. The typical benzodiazepine anxiolytics diazepam (0.05-0.5 mg/kg, i.p.) and chlordiazepoxide (0.5-4 mg/kg, i.p.) dose-dependently increased the number and duration of head-dips at doses that did not produce sedation. In contrast with these anxiolytics, the typical anxiogenic drugs N-methyl-beta-carboline-3-carboxamide (FG7142, 0.125-10 mg/kg, i.p.) and methyl-beta-carboline-3-carboxylate (beta-CCM, 0.1-2 mg/kg, i.p.) decreased both the number and duration of head-dips, and increased the latency to head-dipping. Moreover, decreases in the number and duration of head-dips, and an increase in the latency to head-dipping, were also observed in animals that were exposed to acute restraint stress. These effects of acute restraint stress were suppressed by treatment with diazepam at a dose that alone did not produce significant behavioral effects (0.1 mg/kg, i.p.). In addition, non-benzodiazepine anxiolytic flesinoxan (0.1 mg/kg, i.p.), a 5-HT1A receptor agonist, also had an effect on the restraint stress-induced decrease in head-dipping behavior. The present study shows that the changes in several exploratory behaviors could be objectively measured using our automatic hole-board apparatus. Therefore, this system can serve as a useful tool for evaluating the changes in various emotional states of animals. Moreover, we also found that treatment with anxiolytics or anxiogenics and exposure to acute restraint stress affected head-dipping behavior. These results suggest that changes in head-dipping behavior in the hole-board test may reflect the anxiogenic and/or anxiolytic state of animals.
Department of Pharmacology, Tokyo Medical College, Japan.
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Takeda
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Tsuji
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Matsumiya
D000818:Animals; D014151:Anti-Anxiety Agents / Q000494:pharmacology*; D001007:Anxiety / Q000503:physiopathology*; D002243:Carbolines / Q000494:pharmacology; D002707:Chlordiazepoxide / Q000494:pharmacology; D003292:Convulsants / Q000494:pharmacology; D003975:Diazepam / Q000494:pharmacology*; D005106:Exploratory Behavior / Q000187:drug effects; D018756:GABA Antagonists / Q000494:pharmacology; D019416:Head Movements; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D010879:Piperazines / Q000494:pharmacology; D012149:Restraint, Physical; D013312:Stress, Physiological / Q000503:physiopathology*
D014151:Anti-Anxiety Agents; D002243:Carbolines; D003292:Convulsants; D018756:GABA Antagonists; D010879:Piperazines; C056895:flesinoxan; C035874:FG 7142; D002707:Chlordiazepoxide; C036150:beta-carboline-3-carboxylic acid methyl ester; D003975:Diazepam