Effects of cholecystokinin-related peptides on retention of passive avoidance behaviour

Effects of intraperitoneal administration of cholecystokinin (CCK)-related peptides were studied on retention of single-trial learning passive avoidance behaviour. The COOH-terminal octapeptide of CCK (CCK-1-8-SE), the unsulfated octapeptide (CCK-1-8-NS), as well as the COOH-terminal tetrapeptide of CCK (CCK-5-8), administered immediately after the learning trial, facilitated passive avoidance behaviour. The data indicate that these peptides may influence memory consolidation processes.