The effects of CRF and urocortins on the sociability of mice

Abstract

The aim of our study was to determine the role of corticotropin-releasing factor (CRF), the urocortins (Ucn1, Ucn2 and Ucn3) and their receptors (CRF₁ and CRF₂) in the sociability of mice. Male CFLP mice were administered intracerebroventricularly (icv) with CRF and urocortins alone or in combination with antalarmin (specific CRF₁ antagonist) and astressin_2B (specific CRF₂ antagonist) and then investigated in a Crawley social interaction test arena, that consists of three chambers. An unknown male in a cage was put in the first chamber and an empty cage was put in the opposite chamber. The tested male was habituated with the middle chamber for 5min and then allowed to explore the remaining chambers for 5min, during which the number of entries and the time of interaction were measured. Intracerebroventricular administration of CRF decreased significantly the number of entries and the time of interaction with the unknown male and these effects were blocked by antalarmin, but not astressin_2B. In contrast, central administration of Ucn1 increased significantly the number of entries into the chamber of the unknown male, without changing the time of interaction and this effect was blocked by astressin_2B, but not antalarmin. Central administration of Ucn2 and Ucn3 didn't influence remarkably the number of entries, but it reduced the time of interaction between the male mice. Our study suggests that CRF and Ucn1 may play important, but different roles in sociability, and that Ucn2 and Ucn3, playing similar roles, must be also involved in social interactions.

Keywords: CRF; Mice; Sociability; Urocortins.