Molecular single-cell analysis identifies somatostatin type 1 (sst1) receptors to block inwardly rectifying K+ channels in rat brain oligodendrocytes.

For the first time whole-cell patch-clamp recordings were performed together with a molecular analysis of mRNA expression on single rat cortical oligodendrocytes. The neuropeptide somatostatin (3 microM) was found to rapidly (< 1s) induce a 58 +/- 33% block of the inwardly rectifying K+ current (IKIR). Following recording, the cells' cytoplasm was harvested through the patch pipette and processed for RNA amplification. Polymerase chain reactions on the amplified products showed that of the primers specific for all five somatostatin receptor subtypes (sst1-sst5), only those derived from sst1 amplified cDNA fragments. Sequence analysis of these fragments revealed complete identity to rat sst1 receptors; thus they are probably the major subtype of somatostatin receptors that control IKIR in rat brain oligodendrocytes.