THE EFFECT OF RHAZYA-STRICTA DECNE, A TRADITIONAL MEDICINAL PLANT, ONTHE FORCED SWIMMING TEST IN RATS

Immobility induced by forced swimming is well known as an animal model of depression. Using this paradigm, we have, in the present work, tes ted the possibility that the medicinal plant Rhazya stricta, which has previously been found to affect the monoamine oxidase inhibitory acti vity in rat brain, may have an antidepressant-like action. Rats were,r etreated with various doses (0.025-6.4 g/kg) of the lyophilized extrac t of the plant leaves, or with desipramine (10, 20, and 40 mg/kg) and were subjected to the forced swimming test. The results indicated that the plant extract produced a biphasic (bell-shaped) effect on the imm obility time. The lower doses (0.1, 0.2, and 0.4 g/kg) elicited a high ly significant and inversely dose-dependent decrease in immobility tim e, and the higher doses (0.8, 1.6, and 6.4 g/kg) showed a dose-depende nt decrease in immobility time. Under the same experimental conditions desipramine (20 and 40 mg/kg) produced dose;dependent significant dec reases in immobility time. Following administration of R. stricta (6.4 g/kg) the immobility time recovered progressively with time, and 4 h after its administration the immobility time was about 70% of the cont rol level (statistically insignificant). It is concluded that R. stric ta extract [or component(s) thereof] may possess an antidepressant-lik e effect. (C) 1998 Elsevier Science Inc.