Effects of chronic administration of interferon α A/D on serotonergic receptors in rat brain

The effects of chronic administration of interferon (IFN; recombinant human IFN -alpha A/D) on serotonergic binding sites in rat brain were investigated. IFN was injected daily for 2 weeks at a dose of 100000 I.U./kg, (i.p.) in male Wistar rats. IFN did not alter either [H-3]ketanserin binding to 5-HT2A receptors or [H-3]paroxetine binding to 5-HT transporters. Scatchard analysis of [H-3]8-hydroxy-dipropylaminotelraline (8-OH-DPAT) binding to 5-HT1A receptors demonstrated the presence of high- and low-affinity binding sites in both treatment and control groups. IFN significantly increased both Kd and Bmax measures of [H-3]8-OH-DPAT binding at low-affinity binding sites, but not at the high-affinity sites. These results suggest that IFN affects the low-affinity 5-HT1A receptors sites and may be involved in the development of IFN-induced psychiatric disturbances.