Effects of Chrysin on mRNA Expression of 5-HT1A and 5-HT2A Receptors in the Raphe Nuclei and Hippocampus

5-Hydroxytryptamine-1A and 5-hydroxytryptamine-2A receptors have been widely related to the mechanism of action of antidepressant drugs. However, the influence of the flavonoid chrysin on 5-hydroxytryptamine-1A and 5-hydroxytryptamine-2A messenger RNA receptors in brain and its association to antidepressant-like actions is unknown. Using male Wistar rats, the effects of chronic administration (28 days) of chrysin at 1, 5, 10, and 20 mg/kg and fluoxetine 1 and 10 mg/kg treatments on 5-hydroxytryptamine-1A and 5-hydroxytryptamine-2A receptor expression in the raphe nuclei and hippocampus using reverse-transcription polymerase chain reaction were investigated. The effects of similar doses of chrysin and fluoxetine on the locomotor activity and forced swim tests on day 28 of treatment, and 24 h after withdrawal were evaluated. The results showed that chrysin (1 and 5 mg/kg) deferentially modified the 5-hydroxytryptamine-1A and 5-hydroxytryptamine-2A receptor expression in raphe nuclei and hippocampus, similar to fluoxetine (1 mg/kg). All tested doses of chrysin produced antidepressant-like effect in the forced swim test, which was maintaining even 24 h after withdrawal. In conclusion, chronic chrysin treatment (1 and 5 mg/kg) exerts antidepressant-like effect that could be associated to the 5-hydroxytryptamine-1A and 5-hydroxytryptamine-2A receptors modifications in both brain structures, the raphe nuclei and hippocampus.

Automated summary

The flavonoid chrysin has been shown to modulate the expression of 5-hydroxytryptamine-1A and 5-hydroxytryptamine-2A receptors in the brain, exhibiting antidepressant-like effects similar to fluoxetine.