Human serotonin 5-HT7 receptor: cloning and pharmacological characterisation of two receptor variants

Two splice variants of the 5-HT7 receptor were identified in human brain that differ in the lengths of their intracellular carboxy terminal tail. Identification of the variants of this receptor is of particular interest since the 5-HT7 receptor is known to have a high affinity for a number of antidepressants and is localized in brain regions thought to be implicated in depression. The two isoforms are expressed in roughly equal amounts in various regions of the human brain. When expressed in NIH-3T3 cells, both variants encode functional 5-HT7 receptors, positively coupled to adenylyl cyclase. We suggest that both variants are derived from a single gene by alternative mRNA splicing. Furthermore, our results from Southern blot analysis studies suggest that additional 5-HT7 receptor genes may exist in human.