Cortistatin modulates memory processes in rats

Cortistatin (CST) is a recently described neuropeptide with high structural homology with somatostatin. Its mRNA is restricted to gamma amino butyric acid (GABA)-containing cells in the cerebral cortex and hippocampus. CST modulates the electrophysiology of the hippocampus and cerebral cortex of rats; hence, it may be modulating mnemonic processes. In this study, we have evaluated the effect of CST and somatostatin (SS) on short- and long-term memory (STM and LTM, respectively), as well as on the extinction of the behavior by using the footshock passive avoidance behavioral test. In addition, we tested the ability of both neuropeptides to affect the generation of cAMP in hippocampal neurons in culture. Results showed that the administration of either CST or SS into the hippocampal CA1 deteriorates memory consolidation in a dose-response fashion and facilitates the extinction of the learned behavior. CST was more potent than SS. Likewise, CST increases cAMP while SS decreases it. These results strongly support a modulatory role for CST in memory processes.