Calcitonin gene-related peptide pre-administration acts as a novel antidepressant in stressed mice

neuroscience28 Calcitonin gene-related peptide (CGRP) is a neuropeptide that has potent vasodilator properties and is involved in various behavioral disorders. The relationship between CGRP and depression-like behavior is unclear.
 In the study, authors used chronically stressed mice to investigate whether CGRP is involved in depression-like behavior. After stress exposure, mice exhibited depression-like behavior and decreased CGRP mRNA levels in the hippocampus. 
Although intracerebroventricular CGRP administration (0.5nmol) did not alter depression-like behavior after 15-day stress exposure, a single CGRP administration into the brain, before the beginning of the 15- day stress exposure, normalized the behavioral dysfunctions and increased nerve growth factor (Ngf) mRNA levels in stressed mice.
Furthermore, in the mouse E14 hippocampal cell line, CGRP treatment induced increased expression of Ngf mRNA. The NGF receptor inhibitor K252a inhibited CGRP’s antidepressant-like effects in stressed mice. 
These results suggest that CGRP expression in the mouse hippocampus is associated with depression-like behavior and changes in Ngf mRNA levels.