Effects of central fibroblast growth factor 21 and irisin in anxiety-like behavior

Adipose tissue and skeletal muscle are organs capable of secreting many bioactive molecules, such as adipomiokines that could be possibly involved in mood disorders. In the present work, we investigated the possible behavioral effects of a single intracerebroventricular (i.c.v.) injection of two adipomiokines, fibrobroblast growth factor (FGF)-21 (0.5-5.0 µg) and irisin (0.4-0.6 µg), in male rats tested in the open field and elevated plus maze tests. Prefrontal cortex levels of norepinephrine (NE), dopamine (DA) and serotonin (5-hydroxytryptamine, 5-HT) and the gene expression of catechol-O-methyltransferase (COMT), dopamine transport (DAT) and tyrosine hydroxylase (TH), were measured by high performance liquid chromatography (HPLC) analysis and real-time reverse transcription polymerase chain reaction (RT-PCR). Both FGF-21 and irisin administration induced anxiogenic behavior, increased DA levels in prefrontal cortex, decreased COMT, DAT and increased TH gene expression. In conclusion, in the present study we demonstrated behavioral effects induced by central FGF-21 and irisin injections that could involve increased DA signaling in the prefrontal cortex.