Cortistatin and somatostatin mRNAs are differentially regulated in response to kainate

Cortistatin (CST) is a presumptive neuropeptide that shares 11 of its 14 am ino acids with somatostatin (SST). CST and SST are expressed in partially o verlapping but distinct populations of cortical interneurons. In the hippoc ampal formation, most CST-positive cells are also positive for SST. In cont rast to SST, administration of CST into the rat brain ventricles reduces lo comotor activity and specifically enhances slow wave sleep. Intracerebroven tricular injection of CST or SST has been shown to protect against the neur otoxic effects of kainic acid. Here, we show that CST and SST mRNAs respond differently to kainate-induced seizures. Furthermore, comparison of the up stream sequences from the CST and SST precursor genes reveal that they cont ain binding motifs for different transcriptional regulatory factors. Our da ta demonstrate that CST and SST, which are often co-expressed in the same n eurons, are regulated by different stimuli. (C) 1999 Elsevier Science B.V. All rights reserved.