Involvement of the long-chain fatty acid receptor GPR40 in depression-related behavior.

The functional role of brain G protein-coupled receptor 40 (GPR40) remains unclear. We investigated GPR40 signaling in depression-related behavior in mice via the forced swim test. A repeated but not a single intracerebroventricular administration of the GPR40 agonist, GW9508, reduced the duration of immobility behavior. Moreover, the levels of hippocampal non-esterified docosahexaenoic acid and arachidonic acid were decreased immediately after the forced swimming. These results suggested that brain GPR40 signaling may regulate depression-related behavior.