Comparison of Acute and Chronic Treatment of Diazepam and Ritanserin in the Elevated Plus-maze Model of Anxiety

Abstract

Recently there has been increasing interest in drugs affecting brain serotonergic (5-HT) neurons as putative anxiolytic compounds. The most widely used anxiolytics, the benzodiazepines, are known to influence 5-HT neurotransmission but there is still controversy over whether this action is related to their anxiolytic effect (see Kahn et al., 1988; Thiebot, 1986). In the case of one class of 5-HT compounds, 5-HT2 receptor antagonists, ritanserin has been reported to be effective in the treatment of generalized anxiety disorder (Ceulemans et al., 1985). However, in animal behavioural models of anxiety the picture is somewhat confusing. For example, ritanserin shows no activity (neither anxiolytic or anxiogenic) in the reward/punishment conflict procedure (Ketelaars and Bruinvels, 1989), but these results need to be interpreted with caution as brain 5-HT neurons are also involved in the control of food and liquid intake, and ritanserin increases food intake in satiated rats (Fletcher, 1988).