Modulation by 5-HT_2A Receptors of Aggressive Behavior in Isolated Mice

Abstract

The present study examines whether isolation-rearing affects sensitivity of 5-hydroxytryptamine (5-HT)_2A receptors and the functional interaction between 5-HT_1A and 5-HT_2A receptors in mice. The 5-HT_2A-receptor agonist (±)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI)-induced head twitch response was significantly greater in isolated mice than in grouped mice. DOI increased isolation-induced aggressive behavior, and the 5-HT_2A-receptor antagonist ritanserin decreased it. The 5-HT_1A-receptor agonist (S)-5-[3-[(1,4-benzodioxan-2-ylmethyl)amino]propoxy]-1,3-benzodioxole HCl (MKC-242) inhibited the DOI-enhanced aggressive behavior. MKC-242 inhibited DOI-induced head twitch response. These findings suggest that 5-HT_2A receptors play a role in aggressive behavior in isolated mice and imply that the antiaggressive effect of MKC-242 may be mediated partly by the inhibition of 5-HT_2A-receptor function.