Impact of Noni Juice on Myelin Components, Neurotransmittory and Behavioural Status in Rats Exposed to Immobilization Stress

Several reports indicate that psychological stress and depression are detrimental to health and that chronic stress implicates pathophysiology of mood and anxiety- related disorders, thus leading to several stressrelated complications. The present study focuses on behavioural status and neurochemical variations in myelin of rat brain exposed to chronic immobilization stress and evaluates the effect of fruit juice of noni over changes in the myelin content of forebrain (FB) and midbrain (MB) regions of rats exposed to stress. Immobilization stress (IS) strategy was utilized to induce stress in Wistar rats. Myelin protein was isolated from the MB and FB regions of rats. Assessment of activities of membrane bound enzymes, levels of neurotransmitters (dopamine, serotonin and glutamate of FB and MB) and lipid profile of myelin in addition to behavioural analysis were carried out. The membrane- bound enzymes such as ATPases, 5'-nucleotidase and acetylcholinesterase exhibit significant decrease in their activities both in the FB and MB regions on stress induction, when compared to that of control. The neurotransmitters and lipid profile also show similar pattern among the experimental group. However, administration of noni juice (NJ) in ISexposed rats can significantly alter the activities of myelin-associated enzymes and levels of neurotransmitters and lipid content of myelin (P < 0.05) along with improvement in the behavioural pattern when compared to those of IS rats. These preliminary results set targets for further authentication of the use of NJ against stress. This NJ could become one of the ideal supplements for management of stress-induced neurological disorders.