A somatostatin receptor 1 selective ligand inhibits Ca2+ currents in rat insulinoma 1046-38 cells

Rat insulinoma 1046-38 cells represent a model system to study beta-cell function, The mRNAs for sst1 and sst2, two of the five somatostatin receptors, were detected by reverse transcription polymerase chain reaction amplification in these cells. Displacement binding analysis suggested that sst1 represents the major somatostatin receptor subtype. The sst1 selective compound CH-275 did not inhibit adenylyl cyclases while compounds that activated sst2 did, In contrast, CH-275 caused a marked inhibition of voltage-operated Ca2+ channels while the sst2 specific analog octreotide elicited a less pronounced effect suggesting that in rat insulinoma 1046-38 cells sst1 preferably mediates the inhibition of Ca2+ channels. (C) 1998 Federation of European Biochemical Societies.