Dopamine

Glucose-dependent Insulinotropic polypeptide (GIP) is a peptide hormone of the incretin family. It has growth factor properties and can re-activate energy utilization. In progressive neurodegenerative disorders such as Alzheimer's and Parkinson's disease, energy utilization is much reduced, and GIP has the potential to reverse this. Furthermore, GIP can reduce the inflammation response in the brain and reduce levels of pro-inflammatory cytokines. Tests in animal models of Alzheimer's and Parkinson's disease show good neuroprotective effects.
Here, Nestler and Lüscher link addiction circuits to epigenetic mechanisms that are engaged by drug exposure or reflect life experience. These molecular alterations may not only explain the basis of drug-evoked synaptic plasticity, but may also help understand individual addiction vulnerability.