Fluoxetine Acts as an Antagonist at 5-HT₂C Receptors in the Crayfish Neuromuscular Junction

Abstract

Fluoxetine (Prozac) is a frequently prescribed antidepressant, identified as a selective serotonin reuptake inhibitor. Prozacs function as an SSRI leads to the popular belief that its antidepressant mechanism is related simply to an increased serotonin level in the synapse, due to the blockage of the serotonin reuptake pump. However, while some previous research has suggested that Prozac acts as an agonist, other research has suggested that Prozac also acts as an antagonist of 5HT₂C receptors, a function apparently contradictory to its role as an SSRI. We sought to further elucidate Prozacs effect on 5HT₂C receptors in the crayfish neuromuscular junction. To determine if Prozac acts as an antagonist of 5HT₂C receptors in crayfish Procambrius clarkii neuromuscular junctions, we compared excitatory postsnyaptic potential (EPSP) amplitudes of control/5HT treatments, and control/Prozac and 5HT. Our results suggest that Fluoxetine does indeed act as an antagonist of 5HT2C receptors in the crayfish neuromuscular junction.