Enables G protein-coupled serotonin receptor activity. Involved in several processes, including G protein-coupled receptor signaling pathway, coupled to cyclic nucleotide second messenger; long-term synaptic potentiation; and regulation of amine transport. Located in dendrite and plasma membrane. Human ortholog(s) of this gene implicated in Alzheimer's disease. Orthologous to human HTR6 (5-hydroxytryptamine receptor 6). [provided by Alliance of Genome Resources, Apr 2022]