Y-RECEPTOR SUBTYPES - HOW MANY MORE

The Y-receptors belong to the G protein-coupled receptor superfamily a nd mediate a wide variety of physiological effects, such as regulation of blood pressure, anxiety, memory retention, hormone release and foo d intake. Since the first human Y-receptor was cloned in 1992, the sea rch for additional subtypes has been an area of intense study. Recentl y four new NPY-receptor subtypes have been isolated, revealing surpris ingly limited sequence identity with values as low as 30%. Several rep orts indicate further heterogeneity of this receptor family, for examp le a peripheral Y-2 receptor. However, since many studies have been ca rried out with different peptide analogs and radioligands in different species, there is substantial confusion regarding the pharmacological profile of the receptors. This may have led to an exaggeration of the potential number of discrete receptors.