Secretin, a member of the secretin-glucagon peptide hormone family, is a 27 amino acid peptide that was originally isolated from the duodenum. In the duodenum, secretin is released to stimulate the release of digestive juices in the pancreas. The receptor for secretin is a class 2 (or class B) G protein coupled receptor that signals through Gs to stimulate cAMP production. Along with its traditional role in the pancreas, studies in secretin-deficient mice have shown miscommunication between the CA3 Schaffer collateral and CA1 pyramidal neurons, causing a deficiency in synaptic transmission. This miscommunication of CA1 dendrites is found in Autism, Rett Syndrome, and most forms of mental retardation, suggesting secretin could be a potential target for treatment of these disorders.