The Gut-Brain axis: Bidirectional signaling between the gastrointestinal tract (GIT) and central nervous system (CNS) occurs through spinal afferents and the vagus nerve. This mode of communication is thought to occur through peptides such as Neuropeptide Y (NpY), Cholecystokinin (CcK), ghrelin, leptin as well as by neurotransmitters like dopamine (DA), serotonin (5-HT), GABA, acetylcholine (Ach) and glutamate. Human and animal studies of various diseases demonstrate that these two systems are not exclusive of one another but do in fact show some parallels in terms of expression of pro-inflammatory cytokines and altered physiological functions.