抄録
This experiment was designed to develop a new animal model for anxiety disorder by inducing anxiety using predator to validate the developed model for both benzodiazepine and non-benzodiazepine class of anxiolytics. Anxiety-like state was induced in rats by predator encounter using live cat for a period of 5 minutes followed by resting period of 48 hours and rats were re-exposed to the same environment with audio of recorded cat sound, in place of live cat, to reinforce the contextual cue. There were 10 treatment groups (Control, induced anxiety, alprazolam, diazepam, clonazepam, chlordiazepoxide, buspirone, fluoxetine, escitalopram, and propranolol). The animals were reared according to their ethology and were encouraged to form burrows by providing cages with appropriate geometric configurations, adequate space and correct bedding material. During study, the standardised drug dose was administered to different treatment groups for first five days, and on fifth day they encountered the cat and for subsequent 2 days they were on their regular drug schedule and on 7th day, again exposed to cat sound and studied for 5 minutes in maze. The maze design resembles some features of burrow which facilitates the expression of rat ethology. The result interpreted in a holistic approach incorporating contextual behavioural response. The transit, locomotory, rearing, freezing, and risk assessment measures obtained for different drug treatments revealed the difference between anxiolytic effect from the panicolytic. The average duration of a rear is higher and rearing posture is different in benzodiazepine suggesting panicolytic action but these attributes are absent in the non-benzodiazepine. On contrary, in non-benzodiazepine, the immobile time in open chamber and the average duration of rear did not differ much from the control. The number of entries into intermediate zone was increased in the non-benzodiazepine, average speed and mobile time also increased than non-benzodiazepine. In addition, the number of rears was numerically increased for non-benzodiazepine in the intermediary zone. The results revealed that the developed anxiety animal model not only gives results for both benzodiazepine and the non-benzodiazepines but also differentiates the panicolytic action of benzodiazepines with the anxiolytic action of non-benzodiazepine.
