Brain cholecystokinin as a satiety peptide

Area of Science:

• Neuroscience
• Behavioral Endocrinology
• Pharmacology

Background:

• The role of gut hormones in regulating appetite and satiety is a key area of research.
• Cholecystokinin (CCK) is a peptide hormone known to influence feeding behavior.

Purpose of the Study:

• To investigate the effects of cholecystokinin-8 (CCK-8) on food motivation and intake in rats.
• To determine the dose-response relationship and route of administration for CCK-8's effects on feeding behavior.

Main Methods:

• Rats received intracerebroventricular injections of CCK-8 at varying doses (0.04–0.08 µg/kg).
• Food motivation was assessed by running speed in a runway to obtain food rewards.
• Food intake was measured during a test meal in the home cage.
• Control tests involved running speed to water rewards.
• Intraperitoneal injections of CCK-8 (8.0 µg/kg) were also administered.

Main Results:

• Intracerebroventricular CCK-8 at 0.08 µg/kg significantly reduced running speed to food and food intake for at least 30 minutes.
• Lower doses (0.04 µg/kg) were ineffective, while 0.06 µg/kg showed intermediate effects.
• No significant effect on running speed to water rewards was observed.
• Intraperitoneal CCK-8 (8.0 µg/kg) also suppressed running speed and eating.

Conclusions:

• Central administration of CCK-8 effectively suppresses food motivation and intake in rats.
• CCK-8's satiety effects are specific to food rewards and not general motivation.
• Systemic CCK-8 administration also demonstrates inhibitory effects on feeding behavior.