ABSTRACT
ABSTRACT Serotonin is an important monoamine found in a number of organisms including plants, fungi, invertebrates, and vertebrates. In mammals, it is considered an important neurotransmitter and found in the central nervous system (CNS) as well as the periphery. It exerts its effects primarily via a family of G protein-coupled receptors. In this chapter, signaling via one of its most studied receptors, the 5-HT2A, is discussed. Its canonical signaling pathways, cell-dependent effects, and functional selectivity are addressed. Interaction with other endogenous neurotransmitters, particularly dopamine (DA), is also of importance in determining its function. More recent results of homodimerization of the receptors as well as heterodimerization with other receptors add to the complexity of the behavior of this receptor.
