HOME CAGE AND OPEN-FIELD LOCOMOTOR-ACTIVITY RESPONSES IN SINGLY HOUSED OLFACTORY BULBECTOMISED RATS

Behavioural hyperactivity is one of the most studied consequences of o lfactory bulbectomy in rats. Attenuation of this hyperactivity in an a rena such as the open-field is an indicator of antidepressant activity . However, this response can only be measured at one timepoint because of habituation. We examined an alternative method of detecting locato r activity, the home cage activity response, and found that singly hou sed olfactory bulbectomised (OB) rats exhibited an enhanced nocturnal hyperactivity 2 weeks following surgery. Moreover, single housing prod uced a typical hyperactive response in the open-field which was qualit atively similar to that previously observed when OB rats are group hou sed. A reduction in body weight was observed in OB rats throughout muc h of the first week following surgery when compared with shams. Food a nd water intake were similarly reduced in both groups in the days imme diately following surgery. Thus, this study confirms that the behaviou ral hyperactivity in the open-field is intact following single housing and that home cage activity is a viable alternative for measuring hyp eractivity in OB rats that has the advantage that such activity can be repeatedly measured without the appearance of habituation.