OBJECTIVE

This study was designed to investigate the effect of orexin on anorexia induced by cholecystokinin (CCK),a peripheral satiety signal.

METHODS

We administered orexin A (0.01-1 nmol/mouse) and CCK-8 (3 nmol/mouse) to mice. Food intake was measured at different time-points: 20 min, 1, 2 and 4 h post-intracerebroventricular (i.c.v.) or intraperitoneal (i.p.) administrations.

RESULTS

Intracerebroventricular-administered orexin significantly increased food intake in a dose-dependent manner. The inhibitory effect of i.p.-administered CCK-8 on food intake was significantly negated by the simultaneous i.c.v. injection of orexin in a dose-dependent manner.

CONCLUSIONS

Orexin reversed the CCK-induced loss of appetite. Our results indicate that orexin might be a promising target for pharmacological intervention in the treatment of anorexia and cachexia induced by various diseases.