Regulation and function of somatostatin receptors

Abstract

This review summarizes the latest advances that have been made to elucidate the somatostatinergic system in respect to somatostatin receptor evolution, the development of receptor agonists/antagonists, receptor regulation, signal transduction, effects on cell proliferation, receptor-receptor or receptorprotein interactions and receptor function.

Somatostatin and Alzheimer's disease

“…SRIF exerts its physiological effects via interaction with a family of five G-protein-coupled receptors, termed SSTR1-SSTR5 (Moller et al, 2003;Olias et al, 2004), with two splice variants of SSTR2 having been identified in mouse and rat, SSTR2A and SSTR2B (Vanetti et al, 1992, Vanetti et al, 1993. SSTRs can couple to multiple cellular effector systems, including adenylyl cyclase (AC), Ca 2+ and K + channels, phospholipase A, serine/threonine phosphatases, and tyrosine phosphatases Patel et al, 1995).…”

Novel signals mediating the functions of somatostatin: The emerging role of NO/cGMP

“…A calcium dependent mechanism known M a n u s c r i p t 10 to be important in the synthesis of NO does not seem plausible, since SRIF is known to have an inhibitory role on intracellular calcium levels (Tallent et al, 1996, Cervia et al, 2003, Olias et al, 2004. However, a mechanism involving an SH2 domaincontaining protein tyrosine phosphatase (SHP-1) may be involved, since SHP-1 was…”

“…It mediates a diverse number of physiological actions by interacting with specific receptors in the plasma membrane Thermos et al, 1989, Olias et al, 2004. Five SRIF receptor subtypes have been cloned, namely sst [1][2][3][4][5] , with the sst 2 to exist as two-splice variants sst 2A and sst 2B (Olias et al, 2004; for nomenclature see Hoyer et al, 1995).…”

“…The cloning of the receptors promoted the development of specific SRIF ligands, agonists and antagonists (Rohrer et al, 1998;Bass et al, 1996;Reubi et al, 2000;Hoyer et al, 2004;Tulipano et al, 2002), specific antibodies and genetically modified mice (Kreienkamp et al, 1999;Viollet et al, 2000;Allen et al, 2003;Strowski et al, 2003) An extensive number of studies and a number of reviews Patel 1999;Tannenbaum and Epelbaum, 2000;Csaba and Dournaud, 2001;Olias et al, 2004) have addressed the intracellular signalling pathways responsible for SRIF's diverse actions. The results obtained were mostly from studies performed in cell lines transfected with the recombinant receptors, but also in native systems.…”

“…Initially characterized for its adenylyl cyclase and pertussis toxin sensitive actions (Mahy et al, 1988), SRIF is now known to activate many other effector systems, including phospholipase A2, phospholipase C, and different phosphatases (Moller et al, 2003;Olias et al, 2004). In addition, activation of the receptors leads to the regulation of ion channels, affecting potassium and calcium currents (Meriney et al, 1994;Tallent et al, 1996;Akopian et al, 2000).…”