Kilic, Melis; Karakoy, Zeynep; Halici, Hamza; Cadirci, Elif; Halici, Zekai

Serotonin (5-HT) is a neurotransmitter found throughout the human body that regulates many physiological events arising from the brain and central nervous system (CNS), such as sleep and appetite. However, it has many other functions in systems outside. In addition to the routine expression of 5-HT7 receptors in CNS regions, such as the pituitary gland, spinal cord, and hippocampus, many studies have reported the expression of these receptors in pathological conditions outside. The role of 5-HT7 receptors outside the CNS has been attracting increased attention in recent years. This review highlights the fact that 5-HT7 receptors are associated with diseases and systems beyond the CNS increasing or decreasing in response to cellular changes. Clinical, basic, in vivo and in vitro studies to date are described, but more research is needed to better understand the role of 5-HT7 receptors outside the CNS.