The neurotransmitter serotonin has neurobehavioural actions which include mood, memory, learning and sleep. Beans, the stable diet of Nigerians contains serotonin and its precursor, 5Hydroxytryptophan in significant amounts. It was therefore the aim of this study to find out whether long term consumption of cooked beans (Vigna unguiculata) diet has effects on some neurobehavioural parameters notably; motor coordination and social behaviour using Swiss white mice as experimental animals. Thirty (30) CD1 mice were randomly assigned into three groups, viz; control, cooked beans diet (50% w/w) and serotonin precursor (5HTP) diet (0.2mg/50g w/w) for thirty days. All the mice had access to clean drinking waterad libitum. Before the neurobehavioural parameters were assessed, the phytochemical analysis of the beans, LD of the beans (Vigna unguiculata) and that of the serotonin precursor (5-HTP) was determined. Serotonin concentration was measured in beans using gas chromatography analysis. Motor coordination and social behaviour were investigated alongside food and water intake and body weight change. Involvement of serotonin pathway was investigated using the set of mice administered serotonin precursor for comparison with the beans diet fed mice. Beam walking was used to assess motor coordination, and the nesting score to assess social behaviour. The results showed that food intake was reduced in cooked beans and serotonin precursor diet-fed mice when compared to control (p<0.01 respectively).There was no change in water intake and body weight when compared to control. On the other hand, beans and 5HTP fed mice showed better motor coordination when compared to control. The nesting score showed no significant difference among the groups. Thus suggesting that serotonin may be involved in the action of beans on neurobehavioral parameters. In conclusion, long term consumption of cooked beans improves motor coordination but does not affect social behaviour, body weight change and water intake but reduced food intake. One or the active chemicals involved in these effects following beans consumption may be serotonin.
Cooked beans, Food and water intake, body weight, Motor coordination and Social behaviour