Somatostatin (SSTR2) receptors mediate phospholipase C-independent Ca2+ mobilization in rat AR42J pancreas cells.
Rat AR42J pancreas cells, which express somatostatin-SSTR2 type receptors, responded to SSTR2-selective somatostatin (SRIF) agonist ligands with a dose-dependent increase in intracellular Ca2+. In addition to SRIF-14 and SRIF-28, the most potent SRIF peptides were the cyclic octapeptides, BIM-23014C, BIM-23023, SMS 201-995, and the cyclic hexapeptides, MK-678 and BIM-23027. The SSTR3 and SSTR5-selective ligands, BIM-23056 and BIM-23052, were inactive and weakly active, respectively. None of the SRIF peptides stimulated inositol phosphate turnover, indicating that Ca2+ mobilization was independent of phospholipase C activation. Incubation in calcium-free medium abolished the increase in intracellular Ca2+. These results indicate that activation of SSTR2 receptors in AR42J cells opens cell-surface calcium channels.
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D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D004789:Enzyme Activation; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000494:pharmacology; D010179:Pancreas / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017481:Receptors, Somatostatin / Q000378:metabolism*; D010738:Type C Phospholipases / Q000378:metabolism*
D009479:Neuropeptides; D017481:Receptors, Somatostatin; D010738:Type C Phospholipases; D002118:Calcium