Increased 5-HT2C receptor responsiveness occurs on rearing rats in social isolation
- Cite this article as:
- Fone, K.C.F., Shalders, K., Fox, Z.D. et al. Psychopharmacology (1996) 123: 346. doi:10.1007/BF02246645
- 90 Downloads
To investigate whether isolation rearing alters 5-hydroxytryptamine2C (5-HT2C) receptors, the effect of the serotonin agonistm-chlorophenylpiperazine (mCPP) was examined on elevated plus-maze behaviour, plasma corticosterone and brain 5-HT2C receptor protein levels in rats. There was no distinction between behaviour or corticosterone levels in drug-free isolates or socially housed rats exposed to the elevated plus-maze. The anxiogenic response tomCPP (decrease in open arm entry and time and an increase in stretch attend postures) on the elevated plus-maze was greater in isolation than in socially reared controls without any concomitant difference in the hypolocomotor effect ofmCPP in the two groups.mCPP produced a greater elevation in plasma corticosterone in isolates than in group-housed controls. Hippocampal 5-HT2C receptor protein-like immunoreactive levels were significantly lower followingmCPP than saline only in rats reared in isolation. These results indicate that increased 5-HT2C receptor responsiveness accompanies isolation-rearing and may contribute to the enhanced response to stress and the increased neophobia seen in this animal model of trait anxiety/depression. In isolation reared rats, rapid down-regulation of supersensitive 5-HT2C receptors may occur in the hippocampus following 5-HT agonist challenge.