DEMONSTRATION OF THE BIOLOGICAL-ACTIVITY OF PEPTIDE-FRAGMENTS RELATEDTO HUMAN AND RAT HIPPOCAMPAL CHOLINERGIC NEUROSTIMULATING PEPTIDE (HCNP)

Human and rat hippocampal cholinergic neurostimulating peptides (HCNPs ) are 54.5% homologous; both stimulate acetylcholine synthesis in rat medial septal nuclei cultures. This in vitro system was used to test t he bioactivity of short peptides containing human or rat HCNP sequence s. Peptides with sequences corresponding to the N-termini and middle r egions of both, and to the shared three C-terminal residues were not a ctive. Tetrapeptides and hexapeptides whose C-terminus is this common sequence enhanced acetylcholine production, indicating that the minimu m consensus sequence for HCNP activity is X-Gly-Pro-Leu.