Undergraduate Research at FIU (URFIU) Conference

The Expression of 5- HT2aR And The 5-HT2cR In The Dorsal And Ventral Hippocampus

East and Center Ballrooms

Cocaine use disorder (CUD) affects 17 million people worldwide. The success in recovery from CUD is challenged by vulnerability to relapse driven in large part by cue reactivity (sensitivity to cues previously linked with drug-taking experience) and craving. Recently, the Cunningham group has demonstrated that the 5-HT_2A receptor (5-HT_2AR) and the 5-HT_2C receptor (5-HT_2CR) have oppositional effects on cue reactivity. Specifically, 5-HT_2CR agonists and 5-HT_2AR antagonists reduce cue reactivity in cocaine self-administration supporting the idea of that these two receptors act in opposition to control behaviors related to CUD. Previous work has demonstrated that higher expression of the 5-HT_2AR coupled with lower expression of the 5-HT_2CR in the medial prefrontal cortex (mPFC) is associated with heightened cue reactivity following a period of abstinence. In addition to the mPFC, the hippocampus is another key brain region that plays a critical role in the development of drug-cue associations. It is currently unknown if the expression patterns of the 5-HT_2AR and the 5-HT_2CR are different along the dorsal-ventral axis of the hippocampus. Given the functional differences between the dorsal (dHipp) and ventral hippocampus (vHipp), (i.e. the dHipp regulates cognitive functions and vHipp regulates mood and anxiety), we tested the hypothesis that there would be an increase in 5-HT_2AR in the dHipp and an increase of the 5-HT_2CR in the vHipp. We used immunohistochemistry methods to detect 5-HT_2AR and 5-HT_2CR expressions in the hippocampus in fixed rat brains. Our results indicate that vulnerability to relapse could be driven by altered interactions of the 5-HT_2CR and the 5-HT_2AR within the hippocampus formation.