The effect of nomifensine on the muricide induced by thiamine deficiency

Abstract

We reported that the muricide response induced by thiamine deficiency was inhibited by the administration of 5-HTP and significantly enhanced by p-CPA.Therefore, it was suggested that this response may be related to the brain serotonergic system. On the other hand, the muricide responses were demonstrated to be involved in the brain dopaminergic system; methamphe-temine inhibited the muricide induced by thiamine deficiency, and the muricide response induced by tetrahydrocannabinol was reduced by 1-dopa or amantadine. So, we investigated the effect of nomifensine which inhibited selectively re-uptake of dopamine compared with other antidepressants on the muricide response induced by thiamine deficiency. Male Wister rats(75-85g) were used in this study and supplied with a thiamine deficient diet for 28 days. The occurrence of the muricide was observed between the 14th day and 28th days. Only killer rats were used in the present experiment. It was observed whether the killer rats treated with each of the drugs killed a mouse or not. When 1-dopa(i.p.) or nomifensine(i.p.) was administered for 7 days, the occurrence of muricide was significantly reduced. Furthermore, killer rats treated with nomifensine(i.p. or i.c.v.) or dopamine(i.c.v.) were converted into non-killer rats. Accordingly, it was shown that the drugs had an inhibitory effect on the muricide that was induced by the tiamine deficiency. However, the muricide behavior was not changed by the combined administration of nomifensine(i.c.v.) or dopamine (i.c.v.) after injection of desipramine(i.p.) and 6-hydroxydopamine(i.c.v.). These results indicated that this muricide response may be related to the brain dopaminergic system.