Physiology of Somatostatin Receptors: From Genetics to Molecular Analysis

Somatostatin and Somatostatin Receptors

“…As previously mentioned, coexpression of SSTR subtypes is often seen in various degrees depending on tissue and cell type Reisine and Bell 1995;Patel 1997Patel , 1999Barnett 2003;Moller et al 2003;Gardette et al 2004;Kreienkamp et al 2004). Overlapping patterns of SSTR distribution have been demonstrated throughout the CNS.…”

“…In addition to these classical GPCR features (Pierce et al 2002;Qanbar and Bouvier 2003), various others have been identified including a PDZ (postsynaptic density-95/discs large/ZO-1) recognition domain in the C-terminus of all SSTR subtypes (Kreienkamp et al 2004). Several PDZ interacting proteins have been discovered, specific to each of the five subtypes, presumably implicated in the chaperoning, scaffolding, and transport of SSTRs (Kreienkamp et al 2004). …”

“…Interestingly, hSSTR3 is the only hSSTR that does not contain a cysteine residue downstream from the seventh TM for purposes of palmitylation and hence membrane anchoring however, it does possess an unusually long C-terminus, which may be a characteristic of its unique signaling properties (Sharma et al 1996Sharma and Srikant 1998b). In addition to these classical GPCR features (Pierce et al 2002;Qanbar and Bouvier 2003), various others have been identified including a PDZ (postsynaptic density-95/discs large/ZO-1) recognition domain in the C-terminus of all SSTR subtypes (Kreienkamp et al 2004). Several PDZ interacting proteins have been discovered, specific to each of the five subtypes, presumably implicated in the chaperoning, scaffolding, and transport of SSTRs (Kreienkamp et al 2004).…”

“…The identification of differential SSTR subtypes initially appeared in 1987 from autoradiographic studies on NETs (Reubi et al 1987). Since then, many tumors have been shown to express SSTRs, a characteristic often exploited for both diagnostic and treatment purposes Reisine and Bell 1995;Patel 1997Patel , 1999Barnett 2003;Moller et al 2003;Gardette et al 2004;Kreienkamp et al 2004;Reubi et al 2004). SSTRs are often highly expressed in NETs, in particular, GH-secreting pituitary adenomas and gastroenteropancreatic tumors.…”

“…The expression of SSTR subtypes has been well characterized in human and rodent tissue including various tumors and tumor cell lines by a multitude of techniques such as Northern blot, RT-PCR, ribonuclease protection assay, in situ hybridization, and immunocytochemistry and has been extensively reviewed elsewhere Reisine and Bell 1995;Patel 1997Patel , 1999Barnett 2003;Moller et al 2003;Gardette et al 2004;Kreienkamp et al 2004). The distribution is widespread, with localization throughout the CNS, periphery, often overlapping in subtype expression depending on tissue-and species-type.…”