Neurokinin B receptors are a type of G protein-coupled receptor (GPCR) that bind to the neuropeptide hormone known as neurokinin B (NKB). These receptors are primarily found in the central nervous system (CNS), specifically in areas related to reproductive functions, such as the hypothalamus and pituitary gland.
Neurokinin B is known for its involvement in various physiological processes, including the regulation of hormone synthesis and release, pain perception, and neuroinflammation. The binding of NKB to its receptors triggers a cascade of signaling events within target cells, leading to the activation of intracellular pathways that regulate these processes.
There are two main subtypes of neurokinin B receptors: NK3 receptors and orphanin receptors (also known as NK4 receptors). NK3 receptors are predominantly expressed in the CNS and have a high affinity for NKB, whereas orphanin receptors are widely distributed in both the CNS and peripheral tissues. Both receptor subtypes share structural similarities and activate similar downstream signaling pathways upon activation by NKB.
The activation of neurokinin B receptors can have diverse effects depending on the context and target tissue. For example, in the hypothalamus and pituitary gland, NKB binding to NK3 receptors stimulates the release of gonadotropin-releasing hormone (GnRH), which in turn regulates the production of reproductive hormones such as luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
Overall, neurokinin B receptors play a crucial role in the mediation of various physiological processes, particularly those related to reproduction and hormonal regulation.
