The vomeronasal organ

The vomeronasal organ (VNO) is a chemoreceptor organ enclosed in a cartilag inous capsule and separated from the main olfactory epithelium. The vomeron asal neurons have two distinct types of receptor that differ from each othe r and from the large family of odorant receptors, The VNO receptors are sev en-transmembrane receptors coupled to CTP-binding protein, but appear to ac tivate inositol 1,4,5-trisphosphate signaling as opposed to cyclic adenosin e monophosphate. The nature of stimulus access suggests that the VNO respon ds to nonvolatile cues, leading to activation of the hypothalamus by way of the accessory olfactory bulb and amygdala. The areas of hypothalamus inner vated regulate reproductive, defensive, and ingestive behavior as well as n euroendocrine secretion.