Cholecystokinin-octapeptide effects on conditioned-avoidance behavior, stereotypy and catalepsy

Area of Science:

• Neuroscience
• Pharmacology
• Behavioral Science

Background:

• Cholecystokinin-octapeptide (CCK8) is a peptide hormone with known effects on the central nervous system.
• Investigating the behavioral effects of peripherally administered CCK8 is crucial for understanding its potential therapeutic applications and side effects.

Purpose of the Study:

• To evaluate the effects of peripherally administered CCK8 on signaled-avoidance behavior, apomorphine-induced stereotypy, and catalepsy in rats.
• To compare the behavioral effects of CCK8 with those of tetragastrin and haloperidol.

Main Methods:

• Rats were trained in a signaled shuttle-box avoidance task.
• CCK8, tetragastrin, or haloperidol were administered intraperitoneally (i.p.) or subcutaneously (s.c.).
• Behavioral assessments included avoidance behavior, apomorphine-induced stereotypy, and catalepsy in vertical grip tests.

Main Results:

• CCK8 dose-dependently reduced avoidance behavior, with maximal impairment around 25%.
• CCK8 showed a brief duration of action, affecting avoidance for up to 15 minutes post-injection.
• CCK8 diminished apomorphine-induced stereotypy and facilitated avoidance extinction but did not induce catalepsy.

Conclusions:

• Peripherally administered CCK8 exhibits sedative and neuroleptic-like properties.
• CCK8's effects on behavior are distinct from gastrointestinal effects and do not include catalepsy.
• These findings suggest CCK8 influences specific behavioral pathways relevant to sedation and neuroleptic action.