CLASSIFICATION AND NOMENCLATURE OF SOMATOSTATIN RECEPTORS

There is considerable controversy about the classification acid nomenclature of somatostatin receptors. To date, five distinct receptor genes have been cloned and named chronologically according to their respective publication dates, but two were unfortunately given the same appellation (SSTR(4)). Consensually, a nomenclature for the recombinant receptors has been agreed according to IUPHAR guidelines (sst(1), sst(2), sst(3), sst(4) and sst(5)). However, a more informative classification is to be preferred for the future, employing all classification criteria in an integrated scheme. It is already apparent that the five recombinant receptors fall into two classes or groups, on the basis of not only structure but also pharmacological characteristics. One class (already referred to by some as SRIF(1)) appears to comprise sst(2), sst(3) and sst(5) receptor subtypes. The other class (SRIF(2)) appears to comprise the other two recombinant receptor subtypes (sst(1) and sst(4)). This promising approach is discussed but it is acknowledged that much more data from endogenous receptors in whole tissues are needed before further recommendations on somatostatin receptor nomenclature can be made.